向巴基斯坦售武 接触塔利班：俄罗斯扩大南亚“朋友圈”

The 2024 5^th International Conference on Advanced Materials and Intelligent Manufacturing (ICAMIM 2024) has gracefully concluded in Guangzhou, China, from November 8^th to 10^th, 2024. This prestigious conference, held under the banner of Guangzhou’s “City of International Academic Conferences” initiative, brought together a diverse array of experts, scholars, researchers, entrepreneurs, and other professionals from across the globe. They converged to share their latest research findings, discuss cutting-edge ideas, and explore academic challenges within the realm of advanced materials and intelligent manufacturing.

The development of advanced materials and their corresponding technologies and industries has been regarded as a “national development strategy” for the world’s leading countries and has gradually developed into a new “trump card” in the game among countries. Intelligent manufacturing, with the most technological innovation value, requires a high level of knowledge and technology in the equipment manufacturing industry and a high degree of integration and application of core technologies, new materials, and components. Therefore, ICAMIM 2024 was held to share and discuss the latest research findings in these two domains.

The conference witnessed an impressive turnout, with participants hailing from diverse academic institutions, research centers, and industrial enterprises across the continents. Renowned experts and emerging talents congregated to share their insights and discoveries. The keynote addresses, delivered by eminent authorities in the fields, were a cornerstone of the event. These luminaries expounded on a spectrum of crucial topics, such as the revolutionary impact of nanomaterials on the performance of intelligent manufacturing systems, the synergy between materials science and artificial intelligence in product design and optimization, and the sustainable development strategies for advanced materials in the context of modern manufacturing.

List of Committee Member is available in this pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

? Type of peer review: Single Anonymous

? Conference submission management system: Morressier

? Number of submissions received: 256

? Number of submissions sent for review: 203

? Number of submissions accepted: 147

? Acceptance Rate (Submissions Accepted / Submissions Received × 100): 57.4

? Average number of reviews per paper: 3

? Total number of reviewers involved: 40

? Contact person for queries:

Name: Xuexia

Email: xx.ye@keoaeic.org

Affiliation: AEIC Academic Exchange Information Centre

Dissimilar material welding, especially aluminum/steel welding, is widely researched and applied in industrial manufacturing. However, many hard and brittle compounds will be formed in the Al/Fe dissimilar welding process because of their different properties. This leads to cracking and a consequent reduction in the plastic toughness of the welded joints, which would limit the use of Al/Fe weldments in practical industrial applications. Many studies have inhibited the formation of intermetallic compounds by adding different interlayers to regulate the elements in welded joints. Therefore, high entropy alloys (HEAs) are also used as intermediate layers in the study of Al/Fe welding. This paper reviews the current status of research on welded aluminum/steel materials with high entropy alloys as interlayers. The influence of HEA compositions and welding process on the mechanical properties and organizational evolution of welded joints were compared and analyzed. Studies have shown that the addition of HEAs as an intermediate layer reduces the brittle intermetallic compounds (IMCs) generated by steel-aluminum and effectively improves the quality of welded joints. Further research on the application of HEA in Al/Fe welding is expected to solve the problems existing in Al/Fe welding and has very high research value.

The purpose of this study is to prepare the Al-Mg-Zn-Cu alloy using laser selective melting (LPBF) forming process with composite powder containing Sc and Zr elements. The microstructure change of LPBF 7075 aluminum alloy in-situ process was studied by process optimization. Results showed that the Laser Powder Bed Fusion (LPBF) printing of a composite powder made of 7075 alloys with 0.8% Sc and 0.24% Zr achieved a density of up to 97.7% using a laser power of 140 W and a scanning speed of 200 mm/s. The Al₃Sc and Al₃Zr heterogeneous nucleation formed a fine grain zone, which played a role in crack arrest. The printing defects were mainly the combined effect of ablation and pore defects, resulting in a low density of the material as a whole, and ablation still existed at low power. This study offers an experimental foundation for the cost-effective production of Al-Mg-Zn-Cu alloy using the LPBF process in the future.

Accurate measurement of the photoelastic constant of glass is the basis for accurately obtaining the glass stress. This paper focuses on one method of measuring the photoelastic constant of glass materials. The method is based on the relationship between optical path difference, stress, and photoelastic constant of glass. By discussing the working principle, measuring device, and measuring steps of the method for measuring the photoelastic constant of glass, as well as verifying in detail the diameter of the sample fiber, the wavelength of the light source, and the loading method that affects the measurement results, the method finally obtains the accurate testing conditions. Since human eyes can distinguish whether extinction is over in manual measurement methods and can distinguish light and color differently, this study introduces visual detection technology into the measurement method of photoelastic constant. The software can identify pixels to determine whether extinction is over, making measurement results faster and more accurate.

The H13 hot-work tool steel is renowned for its exceptional toughness, hardenability, thermal strength, and hardness, as well as its outstanding resistance to thermal fatigue and wear, which makes it a preferred choice for hot extrusion dies. This study employed a comprehensive process control methodology, including high-temperature homogenization, precision forging, high-temperature normalization, and isothermal spheroidizing annealing, to optimize the microstructure of H13 tool steel and improve mold quality. The results indicated that the macrostructure of the treated H13 steel was dense and uniform, with no observable segregation defects or impurities. The macrostructure exhibited a general porosity rating of 0.5, with both central porosity and ingot segregation also rated at 0.5. The steel matrix was characterized by a uniform spheroidized structure, with an improvement in the spheroidization grade to AS3. Additionally, segregation phenomena were significantly mitigated, leading to a more homogeneous distribution of internal elements. Post-treatment, the average impact energy of the H13 die steel ranged from 271 to 316 J, thereby satisfying the impact energy requirements established by the North American Die Casting Association for high-quality steel. The optimization of processing techniques resulted in a remarkable enhancement of the microstructure of H13 die steel, thereby significantly improving its mechanical properties.

The effects of Cu content on the microstructure and electrical conductivity of Mg-5.8Zn-1.0Mn-xCu(wt.%)(x = 0 ～ 1.5) alloy were studied by optical microscopy (OM), X-ray diffraction (XRD), Brinell hardness tester, WD-Z eddy current conductivity tester and scanning electron microscopy (SEM). The relationship between electrical conductivity and Cu content of extruded, homogenized, and as-cast alloys was obtained. The research shows that the as-cast alloy is mainly composed of magnesium matrix and eutectic, and the main second phases are the MgZn₂ phase and MgCuZn phase. The increase in Cu content leads to an increase in the proportion of eutectic structure in the alloy. The as-quenched and as-extruded alloys are mainly composed of magnesium matrix and eutectic structure, and the eutectic structure includes the MgZn₂ phase, MgCuZn phase, and Mn element. The electrical conductivity of the as-cast alloy increases after the increase in Cu content due to the increase in MgCuZn phase content in the alloy, and the highest electrical conductivity is 14.33 MS/m. Due to the redissolution of the Zn element into the matrix and the precipitation of the Mn element from the magnesium matrix, the lattice distortion of the homogenized alloy is weakened, and the conductivity of the alloy increases after decreasing first, with the highest increase of 11.8% compared with the as-cast alloy. The MgZn₂ phase is precipitated during the extrusion process, the alloy’s lattice distortion is weakened, and the conductivity of the alloy is increased by 12.7% compared with that of the homogenized alloy.

Azide energetic plasticizers have the advantages of good thermal stability, low glass transition temperature, environmental friendliness, and good compatibility with azide adhesives. In this study, different contents of glycidyl azide polymer (GAP) with a relative molecular weight of 330 were employed for modifying NC-NG-RDX propellant. The thermal stability of the NC-NG-RDX propellant system was assessed by conducting DSC and TG tests to examine the influence of GAP. Additionally, the ARC tests were employed to investigate the thermal decomposition characteristics of a modified triple-base propellant under adiabatic conditions. The temperature corresponding to the 5% thermal weight loss of the GMTP-12 sample in the TG test increased by a maximum of 7°C. Similarly, the ARC test showed a maximum rise in adiabatic temperature by 1.8°C. The VST tests demonstrated the satisfactory thermal stability of the GAP-modified triple-base propellants.

We mainly explore the self-assembly behavior of low-dimensional organic graphene-like molecules at interfaces and the method of preparing nanomaterials with specific functions and structures through self-assembly technology. We have successfully prepared a two-dimensional nanographene film on the surface of boron nitride by in situ UV crosslinking and thermal conversion. The scanning electron microscope and PV current and voltage tests of the film are characterized and studied. The research work in this paper provides help for further understanding of the surface electron distribution of graphene-like materials and edge modification of low-dimensional materials. It also provides a possibility for the application of graphene in the field of integrated circuits.

In order to learn about the propagation traits of Lamb waves in laminated composite panels, the propagation behaviour of Lamb waves in the laminated composite panel shape was once investigated with the use of piezoelectric ultrasonic experiments and laser ultrasonic experiments. Firstly, via wideband linear frequency modulation excitation experiments, the multimodal nature of ultrasonic Lamb waves in laminated composite panels was once observed, in particular the A0 modal and S0 modal, exploring the propagation behaviour of these two modes in laminated composite panels and acquiring the group speed curve of Lamb waves in the laminated composite panel structure. Secondly, by way of the usage of laser linear excitation experiments and two-dimensional Fourier radically change techniques, the wavenumber frequency area picture was once obtained, and the section speed and crew pace dispersion curves of Lamb waves propagating in the shape have been calculated. Finally, with the aid of arranging sensors on the higher and decrease surfaces of the laminated composite panel, differential information on Lamb waves on the higher and decrease surfaces have been obtained, main to conclusions on the isotropic traits of Lamb wave propagation in aluminium plate and rubber laminated composite panel structures.

Lithium manganese iron phosphate was manufactured via the sol-gel method, and the impact of the gel drying method on the electrochemical properties of lithium manganese iron phosphate and the underlying mechanism of action were investigated. The results demonstrate that lithium manganese iron phosphate produced by freeze-drying and sintering the gel exhibits excellent cycling performance, providing a significant discharge capability of 147.0 mAh g^?1 under conditions of 0.1C and a capacity retention rate of 100% after 250 complete cycles under conditions of 1C. This can be attributed to the fact that freeze-drying addresses the agglomeration issue that arises from the conventional drying process. The resulting lithium manganese iron phosphate exhibits a smaller particle size and a more uniform pore structure, which is a consequence of the action of ice crystal separation. This offers a potential avenue for future process optimization in the sol-gel synthesis of lithium manganese iron phosphate.

This article characterizes the thermal stability between electrode and electrolyte materials using two methods: powder mixing co-firing XRD testing and drop-coating method co-firing XRD testing. The highest thermal stability temperature of the electrode and electrolyte materials can be determined, thereby laying a data foundation for future research.

A deep understanding of solid-state phase transformation behavior (SPTB) during the Electron Beam Melting (EBM) process is essential for achieving customized microstructures and properties. This study developed an SPTB prediction model by coupling an equivalent micro-zone heat source (EMHS) model with a non-isothermal Johnson-Mehl-Avrami (NJMA) kinetics model. We investigated the evolution of SPTB in IN738 alloy during a ten-layer, five-track continuous line melting process. The results indicate that the evolution of the γ′ phase can be categorized into three stages: precipitation complete dissolution stage, precipitation partial dissolution stage, and cooling stable precipitation stage. Due to temperature history differences during printing, the γ′ phase exhibits uneven distribution in the powder bed, with maximum volume fractions of 1.015e^?7, 15.86, and 10.06 at the end of printing for the first, fifth, and tenth layers. Following cooling, these values increased to 3.098, 17.85, and 45.65. The model’s validity was verified using literature data. This research enhances understanding of EBM’s relationships between materials, processes, microstructures, and properties.

The microstructure of tungsten-based high-density alloy laser fusion brazed joints was characterized by using optical microscopy, scanning electron microscopy, and X-ray diffractometer in this work. The results indicate that the laser fusion brazing joint includes a fusion welding joint and brazing joint; The weld seam consists of gray α-Ag, black β-Cu, and detached particles of tungsten alloy; β-Cu is distributed in the α-Ag substrate with blocky, rod, and strip morphology, and the layered α-Ag and β-Cu can be seen in some areas. The results reveal that the dominant intermetallic compound in the fusion zone is W particles, γ- (Fe, Ni), and FeNi₃ intermetallic compounds. The dominant intermetallic compounds in the brazing seam are α-Ag and β-Cu. There is a compound-type interface in the laser fusion brazing joint of tungsten-based high-density alloy, and the intermetallic phase in the interface is FeZn₇.

In the field of photoelectric passive interference, spinel ferrite has a significant attenuation ability of electromagnetic waves in the 2-18 GHz cm band. However, in practical applications, it is difficult for ferrite to form large-scale electromagnetic wave attenuation aerosols in the air due to its heavy ratio. In this paper, the magnetic NiFe₂O₄ hollow particles were obtained by preparing them using the hydrothermal method assisted by glucose, which showed excellent electromagnetic loss performance. The changes in particle retention (volume growth value) and electromagnetic wave absorption performance with the hollow rate were analyzed. The electromagnetic wave absorption cross section and relative volume growth value of hollow particles with different particle sizes and hollow rates were obtained by theoretical calculation. The electromagnetic parameters of magnetic NiFe₂O₄ hollow particles with different ratios of glucose and metal ions were measured by Vector Network Analyzer. The effects of ratios of glucose and metal ions on the electromagnetic loss of magnetic NiFe₂O₄ hollow particles were investigated. The ratio of glucose to metal ions has a threshold of 20:11.25. Increasing or decreasing the metal ions will reduce its electromagnetic loss performance. The reflection loss can reach the minimum value of -24 dB at 5.3 GHz.

In order to improve the welding efficiency and performance of aluminum alloy thin-walled structural components in the fields of projectiles, aerospace, and rail transportation, this paper studies the rapid laser self-fusion welding process, joint microstructure, and mechanical properties of 2 mm-thick 6082 aluminum alloy. The results show that through the exploration of process parameters, six groups of welds with good forming and no metallurgical defects are obtained, and the fastest speed reaches 6 m/min. The weld microstructure consists of a large amount of α-Al matrix and a small amount of Mg₂Si phase. The hardness of the welded joint is 75.89 - 79.08 HV, reaching more than 84% of the base metal hardness; the average tensile strength is 224.5 MPa, reaching 81% of the base metal. This is due to the disappearance of the work hardening effect in the weld and heat-affected zone and the reduction of the Mg₂Si strengthening phase caused by the evaporation and burn loss of low-boiling-point elements, resulting in the softening phenomenon. The tensile fracture morphology is a typical plastic fracture feature.

In response to the urgent demand for magnesium alloys in lightweight complex structural components, the CMT arc additive manufacturing process was used to prepare defect-free WE54 magnesium alloy samples, and the microstructure and mechanical properties of the samples in different heat treatment states (deposited state → T4 state → T6 state) were analyzed. The results show that the chemical composition of the deposited state sample has no significant change compared to the welding wire. The matrix is mainly composed of the α-Mg phase, and the second phase is distributed at the grain boundaries and inside the grains is composed of Mg24(Gd, Y)5. The grain size gradually increases, and the degree of axial uniformity of the grains gradually decreases. The ultimate elongation and cross-sectional shrinkage of the T4 state sample are 4.2% and 8.0%, and the fracture characteristic is a ductile fracture. The ultimate tensile strength and yield strength of the T6 state sample are 286 MPa and 207 MPa, respectively. There is no anisotropy in the tensile properties of the three, and the overall mechanical properties are better than those of castings. At the same time, it has demonstrated the feasibility of the CMT arc additive manufacturing process for WE54 magnesium alloy.

The denitrifying deep-bed filter, as an advanced treatment technology for upgrading wastewater treatment plants (WWTPs), is widely employed in the secondary effluent treatment of wastewater facilities. In this study, three denitrifying shallow filters were developed to efficiently eliminate total nitrogen, ammonia nitrogen, nitrates, and suspended solids (SS) from municipal WWTPs’ secondary effluent. Sodium acetate was utilized as the carbon source to assess the denitrification effects of the three filters with different filter materials (quartz sand, polycaprolactone (PCL), and quartz sand-PCL) at varying C/N ratios. Furthermore, biomass and microbial community analyses were conducted using these filters. The findings demonstrate that all three filters exhibited outstanding performance in removing nitrate and total nitrogen (TN). Specifically, the nitrate removal rate exceeded 90% in all cases while maintaining a total nitrogen removal rate above 70%. Both the quartz sand filter and quartz sand-PCL composite filter showed minimal nitrite accumulation. The highest contaminant removal rate was achieved by the quartz sand filter at a depth of 0-20cm, whereas the peak contaminant removal rate for the quartz sand-PCL filter occurred at a depth of 40-60cm. High throughput sequencing and qPCR results revealed that Proteobacteria species, including Gammaproteobacteria and Betaproteobacteriales, dominated in all three filters.

Composite coatings with in-situ-grown ceramic phases were created using Ti-35Al-15Si as the cladding material and laser cladding coaxial powder feeding method. The effect of laser power on the quality, organization, and properties of coatings was examined. The experimental results reveal that as laser power rises, penetrating cracks form in the cladding layer. Its fused cladding layer consists mainly of Ti-Al and Ti-Si phases. When the laser power increases, the dilution rate of the cladding layer also rises, resulting in an increase in the Ti-Al phase and a decrease in the Ti-Si phase. Its fused cladding layer’s hardness and wear resistance declined as laser power increased, peaking at 900 W and 829.36 HV.

Building ceramisite was prepared by oil shale residue, in which the different content of MnO₂ was added. We apply XRD, ultra-depth field microscopy, and other research methods to study ceramisite characterization. Simultaneously, the water absorption, density, and strength of ceramisite were measured. The experimental results show that with an increase in MnO₂ content, the color of the ceramisite becomes darker and darker, and the surface glaze of the ceramisite gradually becomes dense and complete. The density of ceramisite is increasing with the increase of MnO₂ content. The compressive strength of ceramisite firstly increases and then decreases with increasing MnO₂ content. When the content of MnO₂ is 10%(mass), the highest compressive strength is 7.55 MPa. When the content of MnO₂ is 12%(mass), the water absorption of 24 h reaches the value of 12.1%. Based on the various performance of ceramisite, the optimal MnO₂ content is within the range of 10%-12%(mass).

Powder metallurgy 304 stainless steel was prepared in a vacuum. The effects of different Sn content on the microstructure, relative density, and tensile strength of powder metallurgy 304 stainless steel were studied.It shows that with the increase in the Sn content, the pore size of the sintered 304 stainless steel becomes larger and the relative density continues to decrease at the sintering temperature of 1300 °C. The largest relative density is 94.6% when the Sn content is 0.5%. The tensile strength of sintered stainless steel shows a tendency to increase and then decrease with the increasing Sn content. Sintered 304 stainless steel has the highest tensile strength of 475 MPa when the Sn content is 1%.

With the increasing scarcity of resources such as oil, research, and development of new energy has become an urgent task. In the use of new energy, there is a need to use various catalysts. The synthesis of transition metal nickel phosphate is the theme. By adding different molar ratios of sodium chloride, different concentrations of chloride ions can be introduced, making different mirror exposure ratios of nickel phosphate. Its structure is characterized by X-ray diffraction and Transmission electron microscope. The results of experiments show that distinct crystal surfaces of the produced nickel phosphorine catalysts have different specific surface areas and uniform dispersion of nanoparticles. According to our experiments and analysis, when sodium chloride is gradually added to proper proportion, Ni₂P gradually decreases in the sample, and the Ni₁₂P₅ content also increases further. Subsequent research revealed that the catalyst’s structure and characteristics are significantly influenced by the synthesis circumstances and that optimal synthesis conditions can significantly raise the catalytic activity and stability. Encouraging the research and growth of linked subjects is undoubtedly important.

Lead-free piezoelectric ceramics are widely used in actuators, sensors, and transducers due to high piezoelectric coefficients and thermal stability. However, the commonly used strategies for improving the piezoelectric coefficients, such as morphotropic phase boundary (MPB) and polymorphic phase transition (PPT), are ineffective in improving temperature stability. In this work, defect dipoles were introduced into barium titanate to enhance both its piezoelectric coefficient and temperature stability. Donor Nb⁵⁺ and acceptor Li⁺ were doped into BaTiO₃ as defect dipoles, resulting in an increase of piezoelectric coefficient to 267 pC/N and a significant improvement in thermal stability. The decrease in flat free energy and grain size, induced by the doping effect, led to a rise in piezoelectric coefficient. Furthermore, the defect dipoles produce an internal bias field (E_i), thus improving thermal stability by stabilizing the domain. This research provides a hopeful strategy for lead-free piezoelectric ceramics with both high thermal stability and a large dielectric coefficient.

As the advanced equipment manufacturing industry progresses rapidly, mold materials have become an essential part of modern industrial applications. Among these materials, AISI H13 steel is highly valued due to its outstanding hardenability, strength, toughness, and resistance to thermal fatigue. These qualities make H13 steel a preferred choice in demanding applications such as hot forging, die casting, and hot extrusion. This study examined the influence of cryogenic treatment on the microstructure and mechanical properties of H13 steel, utilizing scanning electron microscopy and comprehensive mechanical testing. Findings revealed that cryogenic treatment significantly enhanced the strength and plasticity of H13 steel, with an ultimate tensile strength of 1689 MPa and an elongation of 9.6%. The strength-ductility product reached 16.2 GPa·%, indicating a substantial performance improvement. The research provided valuable theoretical insights for optimizing production process parameters for H13 steel, supporting enhanced industrial performance and reliability.

04Cr13Ni5Mo martensitic stainless steel has high strength, good low temperature toughness, good corrosion resistance and weldability, and it is widely used in the hydropower industry. With the increasing installed capacity in China, especially the impulse hydropower units are rapidly developing towards high head and high-capacity, the demand for large 04Cr13Ni5Mo martensitic stainless steel forgings is increasing, and the performance requirements are also higher. This paper introduces the smelting method, chemical composition, mechanical properties, heat treatment, microstructure and grain refinement of 04Cr13Ni5Mo martensitic stainless steel forgings, mainly analyzes the influence of chemical composition and heat treatment on the properties, and prospects the development direction of domestic 04Cr13Ni5Mo martensitic stainless steel forgings.

The mechanical properties of a material are determined by its microstructure. In this study, the heat transfer and the microstructure of the aluminum melt pool are investigated by means of macro and micro modeling and simulation in the L-PBF process. In this paper, a macro-heat transfer model is proposed to calculate key solidification parameters, such as temperature gradient, solidification rate, and cooling rate within the melt pool. In this paper, the evolution of microstructure and solute distribution in the L-PBF melt pool is analyzed by coupling the solidification parameter data from the macro-heat transfer model with the phase field model. The results of the experiment show that the L-PBF structure is well consistent with the experimental results.

Crippling performance is an essential indicator of I-shaped long stringers used in civil aircraft composite wall panels. In order to study the effect of the composite molding process on crippling performance, this paper studies the effect of co-curing and co-bonding molding methods on crippling performance for I-shaped long stringers with impact damage. Furthermore, under the premise of co-curing molding, the effect of soft film and hard film processes on crippling performance is studied. Test articles were manufactured and tested for verification. The results showed that the crippling performance of co-cured composites was 1.21 times that of co-bonding, and the crippling performance of soft mold composites was 1.08 times that of hard mold, which provides a basis for composite wall panel designers to choose composite molding processes.

With the rapid development of electronic technology, magnetic metal nanoparticles have been extensively utilized in dielectric materials due to their unique structure and properties. This paper synthesizes a series of Ni and NiFe nanoparticles by controlling reaction parameters through a water-phase reduction method and prepares NiFe@PEI composite dielectric films by using a solution casting method. The results indicate that Ni and NiFe nanoparticles with diameters ranging from 40 to 80 nm were successfully obtained by regulating the reaction temperature, with the particle size increasing as the reaction temperature rises. The dielectric constant of the NiFe@PEI dielectric films ranges from 4.24 to 5.07 F/m, exhibiting an upward trend with an increasing mass fraction of NiFe. Furthermore, these films demonstrate low dielectric loss, indicating a promising application potential in dielectric materials.

In this study, we developed a degradable and recyclable conductive adhesive system using polyetheramine D400 and imidazole formaldehyde. This novel epoxy resin matrix incorporates a dynamic imine bond, enhancing the degradation and scalability issues associated with traditional epoxy thermosetting resins commonly used in composites and smart devices. We enhanced this matrix by integrating conductive fillers. Our findings reveal that the adhesive exhibits high shear strength (14 MPa) and low volume resistivity (8.64*10^?5 Ω*cm). The pH-sensitive imine bonds enable the adhesive to degrade rapidly under mild conditions, allowing for the efficient recovery of valuable conductive particles. This approach provides a flexible platform for advancing the functionality and intelligence of traditional thermosetting materials.

This study describes the design and melting of a novel high entropy AlCrFeNiNbx alloy. The impact of various Nb elements on the high entropy alloy’s mechanical characteristics and microstructure was investigated. When the content of the Nb element is 0, the high entropy alloy has a regular shape of the equiaxial crystal and an irregular lamellar structure between the crystals, and the alloy mainly consists of the BCC phase. After the addition of the Nb element, the grain changes from equiaxial to relatively coarse dendrite grains, and the lamellar structure is distributed at the end of some dendrite grains. The dendritic grains get more polished as the Nb element level rises, and certain dendritic ends start to take on a black structure. At this time, the alloy begins to appear B2 phase. When the content of Nb was 0.3, the black tissue of the branches grew. When the content of Nb is 0.6, the dendritic structure grows further and is evenly distributed in the alloy, the black structure becomes smaller, the lamellar structure becomes less and is distributed among the dendritic crystals, and the alloy appears σ phase. The hardness of the high entropy alloy increases with increasing Nb concentration; at its greatest, it is 1.71 times that of the non-Nb alloy. The wear mechanism of high entropy alloys is abrasive wear and adhesive wear, and their wear resistance is strong when the Nb element level is 0.1.

Ion crosslinking stands as an effective method for achieving self-healing properties in rubber materials. In this study, leveraging the reactive nature of zinc oxide (ZnO) and methacrylic acid (MAA) to form zinc methacrylate (ZDMA) in situ, a dual cross-linked network comprising ionic and covalent bonds was established within brominated butyl rubber (BIIR). Investigations demonstrate that BIIR formulations incorporating ion crosslinking exhibit self-healing capabilities even at room temperature. Nevertheless, the material properties exhibit divergent trends concerning mechanical strength and self-healing capacity. Specifically, BIIR-ZDMA10, attained a maximum tensile strength of 6.15 MPa after a positive-vulcanization time, although its healing ability was compromised. Healing efficiency reached 98% at room temperature after 3 minutes of vulcanization, but tensile strength was initially low at 0.43 MPa. Following a 5-minute curing period, tensile strength increased to 4.15 MPa, and after 24 hours of healing at room temperature, it stabilized at 1.13 MPa, demonstrating optimal overall performance. Through meticulous control of the vulcanization process and suppression of covalent crosslink formation, the rubber material demonstrated heightened strength alongside consistent self-healing capabilities.

In this paper, a high-strength Ti-4Al-4Mo-4Sn-0.5Si (IMI551) alloy bar was successfully prepared by fast induction sintering and hot extrusion of the powder compact of blends of TiH₂, AlMo60, and other elemental powders. The microstructure, mechanical properties, and fracture behaviors of the extruded rod were investigated. The results show that the dense titanium alloy with uniform composition and homogenous microstructure can be achieved by sintering the powder compact at the temperature of 1300 oC and holding for 5 min, followed by extruding. The average yield strength, tensile strength, and fracture elongation of the alloy were 1194 MPa, 1344 MPa, and 3.1%, respectively. The fracture mode was mainly intergranular fracture caused by stress concentration at the continuous and long grain boundary α plates.

Sn-3.0Ag-0.5Cu-x Ga₂O₃/Cu solder joints with different contents (x=0wt%, 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt%, 1.2wt%) were prepared by Ga₂O₃ nanosized particles and isothermal aging at 170 °C for distinct time. And the effect of Ga₂O₃ nanosized particles on the interfacial enhancement behaviour of Sn-3.0Ag-0.5Cu solder was dug into. The results show that a proper amount of Ga₂O₃ can impede the enhancement of the IMC layer. When the content of Ga₂O₃ is 0.4%-0.8%, the inhibitory effect of the IMC layer is better. When the content of Ga₂O₃ is 0.4%, the enhancement of the IMC layer is slow, and the diffusion coefficient is 3.34×10-¹⁶m²/s.

Different mortar coarse aggregate strength grades and various mortar coarse aggregate replacement rates were used to study C30 recycled aggregate concrete strength and durability of dry shrinkage. The results show that as the proportion of recycled coarse aggregate to the mortar increased, the concrete mixture became less fluid. Reducing the recycled rough strength caused a steady decrease in concrete strength, even if the replacement rate of recycled coarse aggregate in the mortar was constant. The strength of the concrete also decreased gradually as the rate of recycled crude aggregate used to replace it increased in mortar. This held true for the recycled coarse aggregate mortar strength classes that were similar. For example, using recycled coarse material and a replacement rate of 100% in low-strength mortar decreased the concrete’s strength. The rate of dry shrinkage length in concrete increased in tandem with the rate of recycled coarse aggregate replacement in mortar. The consistency of the recycled coarse aggregate in the mortar had no effect on this. A large dry shrinkage length rate was seen in the concrete when the cannon recycled aggregate’s strength was reduced, leading to a much greater bibulous rate.

Solvent-free alcohol stripping anti-fouling flash coating (SFDA-RTV) is an environmentally friendly coating with excellent rheological properties, electrical insulation, chemical stability, and mechanical properties. This article investigates the effects of different catalytic systems on the rheological properties, curing properties, mechanical properties, electrical properties, and chemical stability of solvent-free dealcoholization anti-fouling flash coatings, and prepares dealcoholization coatings with different catalytic systems. The results indicate that the addition of a composite catalyst of 726/dihexylamine/MgO in a ratio of 1:4:4 can effectively improve the catalytic degree and curing depth of the coating. The addition of a catalyst has no effect on the mechanical properties, electrical properties, and chemical stability of the coating.

Addressing the high deformation rate of Q195 steel chain plates after carburizing and quenching, an experimental investigation was conducted to explore the effects of quenching temperature, medium, and water entry method on the microstructure, hardness, and residual stress of the chain plates. The results indicated that vertical entry into water effectively reduced the surface residual stress, improved its distribution, and enhanced microstructural uniformity. As the quenching temperature and the Polyalene Glycol (PAG) concentration increase, the martensitic microstructure gradually coarsened, while the hardness initially increased and then decreased, peaking at a combination of a quenching temperature of 1, 050°C and a PAG concentration of 5%. When water was used as the quenching medium, the surface residual stress intensified with rising temperature. In contrast, the adoption of 5% PAG significantly decreased the level of surface residual stress. Comprehensive analysis revealed that under the conditions of vertical water entry, a quenching temperature of 1, 050°C, and a 5% PAG quenching medium, the chain plates exhibited optimal microstructural uniformity and mechanical properties, achieving a hardness of 881.2 HV_0.5 while reducing the surface residual stress to -143.4 MPa.

Cutting force is a key factor affecting the machining quality of cycloidal bevel gears. By selecting appropriate cutting parameters to reduce the fluctuation of cutting forces, the machining quality of cycloidal bevel gears can be effectively improved. This paper simulates the cutting process through finite element analysis, aiming to explore the impact of cutting parameters on the cutting forces during the machining of cycloidal bevel gears and their process optimization methods. Firstly, a cutting model of the cycloidal bevel gear is established, followed by the construction of a large gear physical simulation model using ABAQUS finite element software. By setting different combinations of cutting parameters, the triaxial force fluctuation curves of cutting forces are plotted. The effects of three factors: cutting depth, angular velocity of the cutter disk and the workpiece, and the rake angle of the cutter teeth on cutting forces are analyzed. Subsequently, the orthogonal experimental method is used to perform range analysis on cutting forces to explore the influence pattern of cutting forces and select the optimal combination of process parameters. The results show that the main parameter affecting cutting forces is the cutting depth and the optimal level combination for minimizing cutting forces is determined to be: cutting depth of 0.1 mm, angular velocities of the cutter disk and the workpiece at 24.44 rad/s and 11.23 rad/s, respectively, and a rake angle of 13°.

Due to the lack of the corresponding calibration device and national calibration specification, center distance calipers cannot be effectively calibrated, which can lead to inaccuracy of the center distance calipers. To standardize the metrological calibration of center distance calipers, this article designs an adjustable center distance caliper calibration device, which is mainly composed of standard gauge blocks and specially designed accessories. The measurement range of the calibration device is (0～2, 000) mm, with the maximum permissive error of ±(0.80+1.6×10^?5L) μm. Experimental results and uncertainty analysis show that the designed calibration device can completely meet the need of calibrating indication error of center distance calipers. The system is stable in performance and strong in repeated measurement ability, which is of great significance for the effective calibration and improvement research of center distance calipers.

In the drilling process of oil and gas extraction, safety accidents such as well blowouts and well surges are prone. The drilling team needs a large amount of spare weighted drilling fluid to realize rapid well pressure and ensure the safety of the drilling process. To reduce the energy consumption of mixing work and improve the mixing efficiency of aggravated drilling fluids, a new static cyclone mixer is proposed in this paper. In this paper, a numerical simulation of the static cyclone mixer is carried out by using the computational fluid dynamics (CFD) method to simulate the effects of the diameter of the cyclone mixer and the number of blades on the mixing effect, respectively. The diameter and the number of blades of the static cyclone mixer have a great impact on the mixing effect. The results show that when the diameter and the number of blades are increased or decreased beyond a certain value, the mixing effect is not further enhanced.

The arm structure of the industrial robot is the main bearing structure of the mechanical arm, and the mass is relatively large. In this paper, the arm structure is selected for lightweight research. Firstly, the structure of the original steel arm is analyzed by using finite element simulation software to obtain its stiffness and displacement. Then, the carbon fiber-reinforced thermoplastic polymer composite boom structure is designed and optimized according to the principle of equal stiffness. In the finite element model of the arm, the steel material is replaced by thermoplastic carbon fiber composite material, and it is found that the weight of the arm structure is greatly reduced and the original stiffness is not reduced. On this basis, the concept of SMEAR super layer is used to carry out multi-level optimization design, which is optimized step by step from free size, layer thickness, and layer order, and the quality of the composite mechanical arm is further reduced, which verifies the effectiveness of the lightweight design method.

The increasingly severe problems of energy shortages have made people pay more attention to the efficient production, collection, and rational utilization of renewable clean energy. Piezoelectric nanogenerators (PENG) can convert various mechanical energies into electrical energy, making it possible for wearable, implantable, and flexible electronic devices to be self-powered. Piezoelectric nanogenerators based on BaTiO₃-based composite materials are becoming a research focus in mechanical energy scavenging devices. The main research on BaTiO₃-based composite materials has focused on doping, modification, composite, or modification operations to improve its electrical and piezoelectric properties. This article reviews the piezoelectric activity, piezoelectric mechanism, and factors affecting the piezoelectric effect of BaTiO₃-based composite materials. This provides unique insights and development paths for advancing research and practical application of piezoelectric composite materials.

Aiming at the problem that the structure of carbon fiber FDM 3D printing nozzle affects the printing accuracy and quality, this paper selects the heating section, shrinkage angle, and heat dissipation section of the nozzle as the optimization parameters, and takes the average speed and average pressure of the exit section as the optimization indexes, designs the orthogonal test and conducts the fluid simulation, and obtains the degree of influence of the factors on the optimization indexes through the polar analysis of the simulation results, and carries out the multi-objective optimization solving by genetic algorithm to obtain the combination of the structural parameters of the better indexes. Optimization solving is used to obtain the nozzle structure parameter combinations with better indexes. It provides a reference for the optimization and improvement of FDM 3D printing nozzle structure.

In response to the demand for the lightweight main load-bearing backplane structure for use on small micro-nano remote sensing satellites, the structural design and additive manufacturing based on laser powder bed fusion were investigated. The results show that the folded edge structure backplane with a hexagonal outer frame has a higher modal frequency than the original circular structure. When the length of the folded edge structure is 4mm, the deformation of the backplane under full load is minimal. To enhance its load-bearing capacity and ensure conformity with the LPBF additive manufacturing molding mechanism, a 45° chamfer structure is incorporated into the folded edge structure. This modification serves to reduce the maximum deformation to 0.742 μm at full load. Furthermore, the low-order modal frequency is observed to exceed 2740 Hz. Through the folded-chamfer backplane structural optimization design combined with LPBF (laser powder bed fusion) technology, a high load-bearing and lightweight back plate for a main carrier in a micro-nano remotely sensed satellite camera was successfully manufactured. The final optimized structural mass is 0.935 kg, representing a 39.52% reduction in weight, which achieves the design unit’s requirements.

Soft pneumatic actuators, due to their flexibility and ease of deformation, have great application potential in industries such as gripping and handling. The paper presents the design of a parallel dual-channel end-wrapping pneumatic gripper based on a PneuNet-type soft pneumatic actuator. The actuator’s gripping force at the end is enhanced by utilizing two rows of chambers in the dual-channel body, while the wrapping chambers on both sides of the actuator’s end increase the contact area between the actuator and the object being grasped, thereby effectively improving the gripping performance. The reliability of the actuator was verified through a combination of simulations and experiments. Compared to traditional PneuNet soft pneumatic actuators, the actuator designed in this study achieved an end gripping force of up to 1.94 N. Additionally, an experimental platform was constructed, and a pneumatic soft gripper with adjustable spacing was developed. Gripping experiments were conducted on sand molds and other fragile objects with delicate surfaces. The results demonstrated that the soft pneumatic gripper designed in this study applies to a wider range of gripping scenarios compared to mechanical grippers, providing greater gripping force and stability than conventional soft pneumatic grippers.

An absolute pressure sensor based on SOI (Silicon-on-insulator) substrate for thermal runaway detection of lithium-ion batteries is studied. A simulation and analysis of the stress distribution within the rectangular island-square membrane composite structure and the piezoresistor is conducted. A piezoresistive pressure sensor chip with a planar size of 2.5 × 2.5 mm is selected. Research on fabrication processing and packaging methods for the sensor is carried out. The test results demonstrate that the sensor exhibits an accuracy of ±0.2% FS within a pressure range of 50 to 250 kPa when working in a temperature range of -40～120°C. The sensor meets the demand for thermal runaway monitoring of power batteries.

By studying the problems of large machining errors and poor precision in the actual processing of laser numerical control machine tools, in order to improve machining accuracy and production quality, a method of using the American Lion optimizer to optimize the principle of a limit learning machine to control laser numerical control machining errors is proposed. The laser numerical control machining module is developed using an open numerical control system. By simulating non-uniform rational B-spline curves, the input coordinates and output displacements of each servo axis are collected as training samples for neural network data organization and analysis. A PO-ELM algorithm model is proposed to train and test the dataset, analyze the machining error status, and achieve the goal of optimizing laser numerical control machining errors. The experimental results show that the PO-ELM algorithm model can effectively optimize the problem of processing errors in laser CNC machine tools, significantly reduce the root mean square error, reduce the processing error of laser CNC machine tools, achieve high-precision processing, and have good control performance.

Reliability modeling is the basic work of aero-engine reliability system engineering, and the traditional reliability modeling method is no longer applicable to engine body components. In this paper, the reliability modeling method based on the reliability unit is proposed for reliability system engineering in view of the problems of strong fault correlation, large complexity of the reliability model of the engine body parts, and poor correlation between the reliability model and the reliability design evaluation in the reliability modeling of the current engine body parts. Then, based on the established reliability model, the reliability enhancement cost function is quantified based on the traditional reliability allocation method, and the reliability allocation method considering the cost function is established. Meanwhile, for the reliability unit with repeated structure and the same load, the Copula function is used to quantify the common cause correlation, and the reliability analysis considering the common cause correlation is realized. Finally, a case application and validation are carried out with an aero-engine tur-bine rotor system as an object.

Intervention measures are essential in clinically treating significant bone defects or poor osteogenic conditions. Although autologous transplantation is the preferred method, it has the risk of secondary injury and infection. Bone tissue engineering technology uses biomaterial scaffolds and biochemical and biophysical signals to regulate cell behaviour and promote tissue repair. The Endogenous electric field is vital in tissue regeneration, especially in bone. The piezoelectric effect of collagen matrix is closely related to bone growth and remodelling. This study prepared PCL/PTFE composite scaffolds by melting near-field direct writing technology, and an in-situ polarized was realized during the printing process. Then, periodic ultrasonic excitation was introduced to improve the polarized scaffold’s potential attenuation and realize the scaffold’s piezoelectric excitation. The results showed that the in-situ polarized scaffold could significantly promote cell proliferation and osteogenic differentiation under cyclic ultrasound stimulation. The scheme of in situ polarized scaffold combined with ultrasonic stimulation proposed in this study is expected to be applied to repair bone tissue defects and has a broad application potential.

Aiming at the problem that the stamping process design of automobile structural parts is not standardized and overly dependent on experience, this paper designs an intelligent design system of the stamping process based on a support vector machine. The system includes three modules: management data, training model, and design process. The system can save a large amount of stamping process design data in a standardized form in the system, and then obtain a support vector machine regression model. When designing the process, the user only needs to input the geometric parameters, material type, and expected forming quality of the part, and the system will solve the regression model based on the constraint conditions through the PSO algorithm to obtain the best process parameters. In practical application, taking the A-pillar-upper as an example, the measured springback of the part is 2.73, while the predicted value of the model is 3, and the relative error is only 9%, which proves the reliability of the process design using this method.

This study comprehensively evaluated the influence of multiple factors, such as adsorption temperature, desorption temperature, CO₂ partial pressure, and other conditions, on the CO₂ adsorption properties of UTSA-16. Their cyclic stabilities were extensively examined under optimized adsorption conditions. As a result, their adsorption capacities simultaneously decreased with increasing temperature, whereas they increased with increasing CO₂ partial pressure. Their CO₂ adsorption performances remained significantly unchanged over 20 cycles. Therefore, it demonstrated the outstanding progress of UTSA-16 in terms of its CO₂ adsorption performance and cyclic stability.

The characteristics of the welding heat source, the morphology of the molten pool, the formation mechanism of the weld, and the amount of heat input have an important and direct influence on the welding quality and performance of the joint. At present, the empirical curve that depends on the experimental results or the calculation formula of statistics cannot comprehensively evaluate the impact of welding on the mechanical properties of the whole structure. Therefore, this research is based on the finite element analysis technique of Simufact Welding software and analyzes the evolution of the temperature field, stress field, and the deformation of the residual stress in the welding process, and provides a powerful tool and a lot of support for welding technology. The aim of the study is to develop an accurate numerical simulation method for the weld temperature field and a dynamic simulation analysis system for the weld stress field and deformation.

This article takes the sliding support structure of the external window as the research object and changes its structure to reduce mass and stress concentration in order to save materials while meeting structural requirements. Firstly, the digital parameter model of the sliding support structure can be carried out using Creo 3D model software, which allows the parameters to be defined directly within the range controlled by the computer without the need for manual modification of component thickness. ANSYS software is used to perform finite element simulation analysis on the sliding support structure under static loading conditions. Then, within the set threshold, a Kriging model is used to establish a response surface model for sliding support structures with different thicknesses of irregular plates and different gasket diameters. Optimization is carried out under constraint conditions. The stress-strain cloud maps before and after optimization are compared and verified to determine the optimal solution.

The present paper proposes a design methodology for passive flexible spring joints based on the kinematic theory of soft arm deformation elements. Through experimental analysis, the relationship between design parameters and the flexibility of the spring joint is examined, thereby validating both the kinematic theory and parametric design approach. The experimental results show that the spring joint designed by this method can greatly improve the success rate of shaft hole docking, and it has guiding significance for the design of flexible docking devices requiring certain deviation adaptability.

A multi-objective optimization method based on an approximation model is proposed for a 22-ton loader ROPS that needs to be lightweight. A finite element model of the loader ROPS is established, and it is laterally verified according to IS0 3471:2008, which determines that it has a large optimization space. The parametric model of ROPS is established, the corresponding design variables are defined, and then the experimental design is carried out. The experimental data is used to carry out the parameter correlation analysis to exclude the design variables that have a small influence on ROPS, the three approximate models are fitted, the RBF model is selected with the highest accuracy through the error analysis, and the quality of the ROPS is taken as the objective. The maximum load-bearing lateral force, the maximum absorption of the lateral load, and lateral deformation are constrained, and the NSGA -II is combined to optimize the design and verify the results. The results show that ROPS optimized by the described method reduces the total mass by 17.29% and the deformation of ROPS during lateral validation by 40.32% and 9.01% respectively, while satisfying IS0 3471:2008.

CsPbI₃ perovskite light-emitting diodes (PeLEDs) are crucial for applications in lighting and displays. In this study, we introduce 1-naphthyl methylammonium iodide (NMAI), a bulk ammonium salt, enhancing the electroluminescence of the luminescent layer. The remarkable photovoltaic properties of the NMAI-modified quantum dot films led to a significant boost in the performance of PeLEDs. This research presents an effective approach for modifying the surface of small-sized CsPbI₃ nanocrystals (NCs) to attain high emission efficiency in PeLEDs.

Multi-angle transverse laser cladding experiments are conducted using 316L stainless steel powder to investigate the effects of powder feeding rate, laser power, and scanning speed on the cross-sectional size of the cladding layer (cladding layer height, width, and depth) and top offset of the cladding layers at 0°, 45°, 90°, and 135°. Concurrently, the microstructure and hardness of the cladding layer are examined. The results show that increasing the powder feed rate leads to a gradual rise in the cladding layer height from 0° to 135°, with the width initially increasing and then decreasing, and the depth gradually diminishing. The top offset of the cladding layer also increases progressively from 45° to 135°. Boosting the laser power results in the cross-sectional size of the cladding layer increasing from 0° to 135°, with the top offset of the layer also rising gradually from 45° to 135°. Enhancing the scanning speed results in a downward trend in the cross-sectional size of the cladding layer from 0° to 135°, and the top offset of the layer gradually diminishes from 45° to 135°. The deflection angle exerts a minimal influence on the microstructure of the cladding layer. With the increase in the deflection angle, the hardness of the cladding layer shows a general upward trend.

In this study, we developed a statistics-based modelling approach that considers the actual fibre architecture of unidirectional composite materials and validated its accuracy. Initially, fibre centre coordinates and misalignment were extracted from a three-dimensional micro-computed tomography image. Subsequently, we confirmed that the fibre arrangement aligns with a random distribution, and the fibre misalignment follows a normal distribution, providing statistical data for setting up the numerical model. The fibres were generated in MATLAB based on the statistics via reverse modelling. Finally, the comparison between the finite element model (FEM) with fibre misalignment and the FEM with fully straight fibres verified the feasibility of the proposed approach.

Canasite glass-ceramic is a novel material known for its outstanding machinability; however, research on its machining characteristics remains relatively sparse. This study develops a three-dimensional finite element model (FEM) for cutting silicon-alkali-calcium silicate microcrystalline glass using ABAQUS software, followed by a corresponding three-dimensional drilling simulation. The simulation evaluates the axial force, torque, and stress distribution on the workpiece during drilling, while examining the variations in axial force and torque under different spindle speeds and feed rates. Based on these findings, drilling tests were performed on canasite glass-ceramic samples prepared via the sintering method, demonstrating satisfactory hole morphology and offering a reference for subsequent conventional machining of canasite glass-ceramic.

The purpose of this paper is to design and analyze a mechanical system of a four-wheeled eight-wheel drive mobile robot to cope with complex terrain and high-load environments. The walking and steering systems are designed to be independently driven by brushless DC motors for each wheel. The chassis structure is optimized. High-efficiency mechanical transmission devices are used to achieve precise power transmission and control. The designed four-wheeled eight-wheel drive mobile robot can flexibly adjust the steering, smoothly pass through different obstacles, and maintain a good operating condition under high load conditions. It significantly improves mobility and stability in complex terrain, effectively improves power transmission efficiency and system reliability, is suitable for various complex application scenarios, and has a wide range of application prospects.

CuO nanocrystals with different surface areas have been successfully synthesized by the calcination method. The performance of electrochemical sensors for the detection of potassium ferricyanide as a modified glassy carbon electrode was examined. Due to the larger surface area, this modified electrode was observed to improve electrocatalytic performance towards the redox reaction of potassium ferricyanide by increasing anodic and cathodic current. The prepared sensors possess a linear range from 5 μM to 50 mM. The limitation of detection for potassium ferricyanide was determined to be 37.06 μM. The reproducibility and stability of this modified electrode are good. It is applied to the determination of the real potassium ferricyanide samples.

With the rapid advancement of flexible material technology, there is an increasing demand for intelligent actuation materials with self-sensing capabilities to accommodate diverse application requirements in complex environments. This paper proposes a self-sensing artificial muscle based on liquid crystal elastomer (LCE) materials, which integrates sensing and actuation functions to enhance the adaptability and controllability of flexible actuators in challenging conditions. The artificial muscle system combines a low-voltage-driven actuation module with a flexible sensing module. Through the coupling of LCE materials with an electrothermal film, bio-inspired deformation is achieved under low voltage. By incorporating a microcrack-structured grid-shaped flexible sensor, coupled with the actuation module, the system realizes an integrated sensing-actuation functionality, enabling the actuator to dynamically adjust its movements based on sensor feedback. Experimental results demonstrate that the artificial muscle exhibits excellent grasping performance. The self-sensing capability effectively addresses the issues of insufficient actuation force and lack of feedback in traditional actuation materials, providing a novel solution for the integrated design of sensing and actuation in flexible actuators.

Single-channel multi-layer welding is a crucial method in wire arc additive manufacturing (WAAM). The characteristics of the arc extinguishing area importantly affect the weld bead profile. To investigate the influencing mechanisms, a three-dimensional (3D) numerical model was developed for the tungsten inert gas (TIG) welding process in WAAM. This model specifically studied the five-layer single-channel welding process under consistent parameters, with experimental verification conducted. The findings indicate that, in a single-direction single-channel multi-layer welding process, the central temperature of the weld pool is higher, and the flow rate is faster. As the increases of the number and height of welding layers, the width of the molten pool in the arc extinguishing area expands, while the temperature at the weld pool’s tail decreases, resulting in a gradual reduction in flow rate. Initially, the molten pool flow is directed from the arc center and the tail toward the sides (in the first layer) but shifts to flow toward the back of the weld pool as more layers are added. In this multi-layer welding process, the fused layer at the arc initiation is considerably higher, while the fused layer in the arc extinguishing area is lower. The simulation results align closely with the experimental outcomes, providing valuable theoretical insights for enhancing the appearance of the arc extinguishing area.

Microelectromechanical system (MEMS) microphones have achieved a great variety of applications like mobile phones and wearable devices due to their small volume, strong heat resistance and high stability. However, the thermal stress induced by temperature variation in packaging and service conditions greatly influences the performance of packaged MEMS microphone devices. We study the thermal stress development in a new type of MEMS microphone with a dual-diaphragm using the finite element method, focusing on influences of the geometrical parameter and different material properties of the adhesive as well as the diameter of the acoustic diaphragm in this paper. It is found that the thermal stress concentrates in the adhesive layer of the dual-diaphragm MEMS microphone and the top diaphragm remarkably, and the stress level can be significantly reduced by decreasing Young’s modulus of the adhesive. The CTE (thermal expansion coefficient) of the adhesive has a much larger effect on the thermal stress in the adhesive layer than that in diaphragms. We also found that moderate adhesive thickness can reduce thermal stress to a great extent. In addition, the diameter of the diaphragm does not affect the maximum thermal stress significantly. The results provide a guideline for low-stress packaging of MEMS devices.

During long-term use, eddy current sensors may experience significant errors or even inaccuracies in their indication values due to aging or the influence of objective environments. Therefore, it is necessary to regularly perform dynamic or static calibration based on the performance of the eddy current sensor to promptly identify and address any issues with the sensor. Currently, most eddy current sensors used in the industry are calibrated manually or semi-automatically, resulting in low calibration efficiency and accuracy. In response to the demand of the metrology department to improve the static calibration efficiency of eddy current sensors, a combination of stepper motors and grating feedback is used to measure the position of eddy current sensors during the calibration process. An integrated automatic calibration control system for the dynamic and static characteristics of eddy current sensors is studied. The design of the calibration system includes the design of the actuator and the design of the control system. Firstly, the overall structure of the control system software is designed. The control system mainly completes the control of the stepper motor and the measurement of sensor displacement, as well as the design of the data acquisition module and data storage module. Through experimental verification, the displacement control error of the static calibration device for eddy current sensors is less than 3 μm, and the accuracy meets the design requirements of 5 μm. The displacement measurement error is less than 3 μm, and the accuracy meets the design requirements of 3 μm. The voltage measurement accuracy reaches 0.1%, and the design meets the requirements of the design indicators.

An articulated pipeline walking robot is proposed, which is a robot that can walk on the outer surface of the pipeline with a turning transition and certain climbing ability and can replace the traditional method to improve the efficiency of pipeline inspection and maintenance and reduce the safety risk of manual work. The gait of the outside pipe walking robot is studied. The traveling mode of the outside pipe robot for climbing horizontal pipes, L-type pipes, T-type pipes and other pipeline systems is analyzed. The robot’s gait is analyzed using the D-H coordinate method, which shows that the proposed design of the outside pipe inspection robot is feasible.

Quantum dots have won the 2023 Nobel Prize, and due to their advantages, such as high purity and adjustable emission wavelengths, they have been widely applied in fields such as display and anti-counterfeiting. However, for perovskite quantum dots, the commonly used hot injection method for synthesis often results in quantum dots with numerous defects and a tendency for ligand dissociation. Addressing these issues, we have introduced diphenyl disulfide during the ligand-washing process based on the hot injection method to further modify the quantum dots. The finally synthesized quantum dots exhibit high fluorescence quantum yield. We have demonstrated through TRPL and PLQY that the performance of quantum dots has been improved in various aspects after modification with diphenyl disulfide, and while their optical properties are enhanced, their electrical performance has also been significantly improved: the device efficiency has increased from 1.15% to 3.35%, and the brightness has increased from 904 cd m^?2 to 9450 cd m^?2. This indicates that the method has effectively improved the synthesis of quantum dots and holds considerable application value for the future quantum dot light-emitting display industry.

Glass substrate is suitable for 3D IC applications due to its low dielectric constant, high transparency, and adjustable thermal expansion coefficient. This paper explores a Through Glass Via (TGV) metalization strategy based on the Electro-hydro-dynamics (EHD) printing process. The research involves using nano-silver ink and adjusting the applied voltage. A 0.2mm thick polydimethylsiloxane (PDMS) film is attached to the bottom of a glass, and the top of the glass undergoes oxygen plasma treatment. These steps facilitate the hovering filling process. Furthermore, the study also examines the effects of process parameters particularly applied voltage, on the cone-jet flow rate and direct current resistance. These provide new ideas for filling TGV.

This study investigates the impact of carbon nanotube bundles (CNTBs) on the static and dynamic mechanical properties and the electrical conductivity of Soluble Styrene Butadiene Rubber (SSBR) composites. The results show that the CNTBs employed exhibit excellent orientation and dispersion within the rubber matrix. The CNTBs form a strong bond with the matrix. Compared to the control group, the loss factor (tanδ) remains relatively unchanged within a deformation range of 1% to 10%. In terms of electrical conductivity, the volume resistivity of the CNTBs/SSBR composite is merely 1/6, 500 of that of the control group, and it is capable of meeting the conductivity requirements for tread rubber applications.

In this study, the porous structure of TPMS is designed and prepared by additive manufacturing technology (AM). The deformation behaviors of these structures are investigated. The results demonstrate that the Gyroid structure exhibits excellent mechanical properties with a strength limit of 372 MPa. The layer-by-layer damage is the process of destruction demonstrated by the Gyroid porous structure. At 30% strain, a diagonal shear band appears, and the angle of the shear band is 45° from the compression direction. Diamond and Primitive porous structures initially exhibit damage at the junction of the unit cell, with a shear band appearing at 20% strain.

Micro-truss structures are lightweight, highly versatile, and strong structures made of linked pillars that are frequently employed in medical and aeronautical applications. The mechanical characteristics of the micro-truss structure in laser powder bed fusion (L-PBF) technology manufacturing are directly influenced by the strength of the pillars. Consequently, the size effect of the pillars is a significant component in determining the mechanics of the micro-truss structure parts. In order to reduce the influence of size effect on the mechanical properties of sub-millimeter-diameter samples, tensile samples with a rod diameter of 0.6 mm were manufactured by L-PBF technology. An analysis was conducted on the impact of various scanning procedures on the microstructure and mechanical properties of the samples. The test results suggested that using a scanning method that includes the insertion of a boundary layer could lead to the concentration of heat in the center area of the sample, the clustering of elements, and the creation of pore defects. These factors significantly diminished the mechanical properties of the sample.

Aiming to address the problem of traditional robot joints not having the ability to perform three-degree-of-freedom omnidirectional movement, the C₆₀ configuration robot spherical joint is designed. Dynamics analysis is performed to achieve precise control of the rotational motion of the spherical joints. Firstly, the spherical joints of a C₆₀ configuration robot with three degrees of freedom and omnidirectional motion capability are designed. Next, the principle of motion of the spherical joint is analyzed. Then, a mathematical model is established for the coordinate position of the permanent magnet and PCB solenoid coil. The drive unit that can provide magnetic force for the target direction is selected, and the robot’s spherical joint voltage control strategy is proposed for experimental validation. It is shown that the spherical joints of the C₆₀ configuration robot have perfect symmetry, achieving a lightweight design and omnidirectional rotational motion in three degrees of freedom. A voltage control strategy for robotic spherical joints is proposed to improve response speed, reduce control complexity, and realize efficient and high-precision control.

In this paper, plasma oxinitriding treatment was performed for hot die steel H13. The temperature of plasma oxinitriding was 550°C, with a holding time of 5 hours. The flow rates of nitrogen and hydrogen were 200 and 800 ml/min, respectively. The oxygen flow rate was 10 ml/min, and the pressure was 300 Pa. After plasma oxinitriding treatment, microhardness measurements and friction and wear experiments were performed on the samples. The microstructure of samples was observed through an optical microscope. The results showed that after plasma oxinitriding treatment, the surface hardness of the samples increased from 465 HV0.3 to 1361 HV0.3, and the case depth was 91.27 μm. The friction and wear performance of hot die steel H13 was improved obviously after plasma oxinitriding treatment.

The active sound absorption method has better sound absorption under low sound waves, but the sound absorption effect is very poor under high sound waves. In order to solve this problem, a semi-active sound absorption method is proposed, which can change this problem by adjusting the surface impedance of the loudspeaker behind the sound absorption material. Firstly, the controllable loudspeaker is placed behind the sound-absorbing material, and its surface impedance is adjusted to make it match the impedance of air optimally to realize the effective adjustment of sound absorption performance. A semi-active sound absorption method can adjust the absorption coefficient effectively under the condition of changing incident frequency and always keeping the sound absorption coefficient at the maximum value.

Electric propulsion is a promising technology for the upcoming satellites, but the sputtering between energetic particles and the inner surface of the thruster may cause damage and limit the operational duration of the thruster. This work explores the protective effects of a monolayer graphene sheet covered on an aluminum surface subjected to xenon ion (Xe) bombardment by molecular dynamic simulations. Xe with diverse kinetic energies (10 eV～100 eV) at various incident angles is considered to inspect the protection capability of graphene. It is found that the existence of graphene coating prevents Xe from damaging the substrate. It is anticipated that the research may facilitate the advancement of graphene-based materials in electric propulsion.

In this study, the infrared heating temperature field in the dry expansion process of the heat shrink tube was numerically simulated and optimized. A temperature field model was established based on COMSOL, and the effects of heating power, distance, and heating time on the uniformity of temperature distribution were investigated. The optimization results show that after improving the heating parameters, the uniformity of the temperature field is significantly improved, the heating rate of the heat shrink tube surface can reach 492 °C/min, and the surface temperature difference is 1.16 °C. This study provides theoretical support for temperature control optimization in the production of heat shrink tubes and has application values of improving process accuracy and efficiency.

To improve the aging and life span of diamond circular saw blades, this study introduces the bionic design theory into the design of diamond circular saw blades’ cutting heads by using the Scapharca subcrenata as a template. The performance of the bionically designed diamond circular saw blades was analyzed to understand their wear resistance and drag reduction mechanisms. Findings indicate that these blades exhibit an 8%–15% reduction in sawing force and a 5% increase in wear resistance compared to traditional counterparts. The bionic non-smooth surface structure enhances the retention and expulsion of cuttings by the diamond nodes within the sawing arc. Additionally, this surface structure improves cooling and lubrication at the nodes, reducing friction between the nodes, stone, and sawdust, thereby enhancing rock-breaking capabilities and overall saw blade performance.

GaAs, as an excellent semiconductor material, have a wide range of applications. Numerous studies focus on the preparation of GaAs, yet they often overlook the critical aspect of thin film growth under conditions of temperature non-uniformity. Investigating this factor is essential for understanding the thin film growth process comprehensively. Consequently, this study utilizes the molecular dynamics technique to simulate the growth of GaAs in non-uniform temperature environments. The variations in temperature are categorized into three types: continual temperature increase, central high temperature, and edge high temperature. By examining the surface morphology and atomic configuration of the films under these conditions, we investigate the impact of temperature non-uniformity on film growth. Our aim is to provide practical manufacturing guidance based on theoretical insights.

Defects on the surface of InP quantum dots (QDs) often result in low photoluminescence quantum yields (PLQY). Herein, in order to improve the PLQY of InP QDs, Ga-doping was used to reduce the surface defect states of InP QDs and improve the PLQY. Firstly, Ga-doped InP QDs (Ga:InP QDs) were synthesized by the growth doping method, and the size uniformity, absorption spectra, and fluorescence spectra were characterized. Secondly, the effects of growth temperature and Ga doping concentration on the optical properties of QDs were studied. The experimental results show that the synthesized Ga:InP QDs are uniform in size, and their PLQY is significantly improved. The fluorescence color of Ga:InP QDs can be tuned by adjusting the In/P ratio and growth temperature. Synthesized Ga:InP QDs exhibited greatly increased PLQY up to 14%. In contrast, without Ga-doping, the PLQY of InP QDs only attained 0.4%. After subsequent coating with a ZnS shell, the resulting Ga:InP/ZnS core/shell structure QDs reached a high PLQY of 70% with a fluorescence emission at 640 nm.

This research, based on structural mechanics theory and using finite element analysis methods, establishes a finite element model for the composite-material box structure of certain shipboard equipment, thereby analyzing the stress situation of diverse stress parts of the box under various working conditions. In this foundation, this research further determines the stress deformation and equivalent stress distribution cloud maps of composite-material box structures under various working conditions, proving that the strength of composite box structures under normal working conditions meets practical usage requirements. Concurrently, in response to the common debonding defects of composite materials, this research investigates the stress changes in the box under debonding conditions, focusing on the influence exerted by different debonding areas on the stress parts of the composite box. The analysis results reflect that if the box undergoes debonding under the same working conditions, the equivalent stress of the composite material box structure will significantly increase. However, the size of the debonding area has little effect on the change of the equivalent stress of the box. The simulation results provide important technical support for applying composite materials, design optimization of the box, and state monitoring.

The die-filling process is a crucial step in powder-forming technology, directly impacting the final quality and performance of powder products. The mechanism underlying how air, as a fluid medium, influences the uniformity of the die-filling process remains unclear. This study, leveraging CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) coupling technology and adopting the Die filling drag force model suitable for a wide range of void fraction variations, investigates the impact of air on the segregation behavior of binary particle mixtures during vertical and mobile die filling processes. By establishing a novel local segregation index, we achieve a precise quantitative assessment of the degree of segregation during the die-filling process. The research findings reveal that vertical and mobile die-filling processes exhibit distinct segregation mechanisms. Specifically, the segregation trend during the vertical die-filling process in the air is pronounced, whereas the mobile die-filling process in an air environment ameliorates surface segregation phenomena through specific mechanisms.

A numerical model for laser-arc composite welding, integrating Gaussian surface and body heat sources, was validated experimentally. By varying welding speeds, the heat-affected zone (HAZ) width and melt pool depth were measured. Results showed wider HAZ and deeper melt pool at 5 mm/s, narrowing and shallowing at 10 mm/s, and narrowest/shallowest at 15 mm/s. COMSOL simulations under the same conditions mirrored these findings, confirming the reliability of the combined Gaussian heat source model.

Due to its large current capacity and high current efficiency, Al-based anode is widely used in marine environments. However, dense corrosion product is formed in a tidal environment, which greatly inhibits the cathodic protection. Therefore, in this paper, an experimental device was established to simulate the tidal environment, and the working characteristics and activation mechanism of three modified Al anodes were studied. The results presented that the actual current capacity of the Al-1 anode and Al-3 anode were better than the national standard Al anode, and the stable anode current densities were 128 μA/cm² (Al-1 anode) and 70 μA/cm² (Al-2 and Al-3 anodes). In conclusion, the Al-1 anode was more suitable for the tidal environment, mainly because the Sn-In solid solution and reduction process of GaO₃^3- promoted the continuous dissolution of corrosion product on the surface of the Al-1 anode in the tidal environment.

Experiments on the laser welding process with different parameters of ultrasonic power were carried out on AA7075/AA2195 dissimilar aluminum alloys and compared with conventional laser welding. The effect of different ultrasonic powers on microstructure and mechanical properties was investigated. The effect of ultrasound on stomatal elimination and grain refinement was further discussed. The results showed that the combined effect of mechanical vibration, cavitation, and acoustic flow effects combined to enhance the stirring effect of the molten pool and accelerate the discharging of gas bubbles from the molten pool. The porosity decreased significantly after applying ultrasonic vibration. At an ultrasonic power of 80 W, the porosity was 0.62%, and there were no large-sized pores. In addition, the average microhardness value in the welded joints increased, and the hardness distribution in the welded joints was more uniform. The tensile strength of the joints after applying ultrasonic power was up to 285.8 MPa, which was an increase in tensile strength of about 25%.

This study investigates how different fiber types enhance the mechanical properties of simulated lunar soil-based polymers. Basalt fiber, polyvinyl alcohol fiber, and polypropylene fiber were selected as reinforcing materials for the experimental analysis of mechanical properties and flexural toughness. The results indicate that polypropylene fiber significantly improves the mechanical properties of the simulated lunar soil-based polymer, achieving maximum performance at a doping rate of 0.4 wt%. The compressive strength, flexural strength, and mid-span deflection increase by 54.5%, 117.7%, and 90%, respectively, compared to the baseline group F0. The enhancement effects of basalt fibers and polyvinyl alcohol fibers on the mechanical properties of the polymer are relatively weak. Using the bending toughness coefficient to quantify the toughening effect of fibers, the effectiveness of the three types of fibers in toughening the lunar soil-based polymer ranks as follows: PP > PVA > BF.

Acoustic emission characteristics of s30408 austenitic stainless steels during tensile test were investigated in this study. Few high-amplitude(>60db) events were detected in the initial yielding stage for all s30408 samples. As the strain further increases, more strain energy is released, and high-amplitude acoustic emission signals are detected in stage 2. More high-amplitude(>60db) events were observed with a strain rate of 2 and 0.5 mm/min. An inflection point is observed for all samples during the strain hardening region, and the cumulative energy increased noticeably with a decrease in strain rate. Tensile strength of s30408 diminishes progressively as the strain rate increases, while yield strength did not change significantly.

This study aims to explore the feasibility of using a Laser Doppler Vibrometer (LDV) as a non-contact acoustic emission (AE) monitoring tool in the tensile testing of carbon fiber reinforced polymer (CFRP) composites. By comparing the performance of conventional piezoelectric AE sensors with LDV, the strengths and limitations of both techniques in damage monitoring were investigated. The experimental results show that LDV not only effectively captures high-frequency damage signals such as microcracks and fiber fractures but also exhibits significant advantages in high-frequency response and non-contact measurement compared to traditional AE sensors. This research demonstrates the potential of LDV technology in CFRP damage monitoring, especially in its superior sensitivity to high-frequency damage events.

This paper presents a simulation analysis of the Roll-Over Protection Structure (ROPS) for a crawler pipelayer’s cab, focusing on the impact of weld seams on performance. Comparative simulations with and without weld seams were conducted using Ansys Workbench. The results indicate that the weld presence can enhance lateral energy absorption by up to 731.21 J, with an average increase of 4.405%. The study also utilized the XGBoost algorithm to predict weld fractures and applied birth-death element technology to manage them effectively. The findings provide new insights into the design of ROPS for crawler pipelayers, highlighting the importance of considering weld impacts in simulation analysis and providing a theoretical basis for further structural optimization.

High-strength wear-resistant steel is a kind of high-performance material that is widely used in wear environments. Its purpose is to slow the wear and consumption of mechanical parts and make the mechanical equipment run safely and stably. However, its wear resistance deteriorates when the load is large, so it is necessary to strengthen its surface. The impact of different laser power settings on the microstructural properties and wear resistance of the cladding layer was investigated through the application of a nickel-based alloy coating on the surface of NM400 steel. The findings suggest that an elevation in laser power leads to an expansion of the melting width within the cladding layer. Accompanied by an enhancement in the dimensions of both the columnar and cellular crystal structures. The hardness exhibits a notable increase followed by a subsequent decline with rising laser power. Additionally, the coefficient of friction decreases markedly, with adhesive wear identified as the primary wear mechanism. The optimal process is 1000W, the average hardness is 575HV_0.2, the friction coefficient is 0.35, the wear scar width is the smallest, and the wear condition is the lightest. The findings of the research establish a theoretical foundation for future surface modification endeavors.

Rolls are prone to surface wear, fracture, and other defects during operation. To investigate the enhanced performance of 9Cr5Mo roll steel, the surface integrity and microstructure of roll steel following warm shot peening were analyzed under varying quenching parameters. The results showed that with increasing quenching temperature, the hardness of the specimen and the residual stress first increased and then decreased, and the surface roughness first decreased and then increased. The hardness and residual stresses of the specimens were greater and the surface roughness was smaller when quenched at 1030°C. It was found that due to the warm shot peening producing residual stresses on the surface of the specimen, martensite was more likely to form on the near-shot-peened surface than on the far-shot-peened surface.

This article investigates the effects of different aging regimes on the microstructure, mechanical properties, and impact toughness of Al-Zn-Mg alloys. The mechanisms by which microstructural changes influence mechanical properties and impact toughness are discussed. In an overaged condition, as aging temperature is elevated and aging time extends, intragranular precipitates become coarser, and the density of precipitates decreases, leading to a decline in yield and tensile strength properties. However, it narrows the strength gap between intragranular and intergranular regions, enhancing the impact toughness. The appearance of the equilibrium η phase and the expansion of PFZ are also reasons for the improved impact toughness of the alloy.

The Ti-0.3Mo-0.8Ni titanium alloy was subjected to an annealing process. Subsequently, the influence of annealing temperature on its microstructure and tensile properties was examined using an optical microscope, scanning electron microscope, and room temperature tensile test. The results show that when the annealing temperature is within the two-phase region, the alloy’s microstructure consists of both primary alpha and beta phases. As the temperature rises, the proportion of the primary α phase diminishes, concurrently with an increase in the beta phase content. Additionally, there is a significant increase in the volume of the secondary α phase. When the annealing temperature is in the single-phase region, the primary α phase in the microstructure disappears completely, and the microstructure is dominated by coarse β grains. There is an obvious grain boundary α phase. With the increase of annealing temperature, the strength of the alloy increases, while the plasticity of the alloy shows an opposite trend. When the annealing temperature is in the two-phase region, there are a large number of equiaxed dimples in the fracture morphology. When the annealing temperature increases to the single-phase region, the fracture morphology is rock-like, and there are obvious tearing edges.

Energy transition is the key to solving environmental problems in the energy sector, and the development and utilization of clean energy and industrial energy conservation are more effective solutions. Among them, the application of the energy storage system is an important link, and the performance of the heat storage molten salt will directly affect the conversion and utilization of the entire energy heat exchange system. In this paper, a kind of NaCl-KCl-FeCl₃ mixed chloride molten salt with a mass ratio of 35:10:55 was prepared by the grinding method, using synchronous thermal analyzer (STA), transient plane heat source method, microscopic morphology analysis, and corrosion dynamic curve to characterize the melting point, thermogravimetry, thermal conductivity, and corrosion properties of the material. It was found that the melting point of the ternary chloride is 140.4°C, the molten salt can work stably at high temperatures, and its thermal conductivity increases with the increase in temperature. The 316L steel sheet is mixed with NaCl-KCl-FeCl₃ at 350°C among the chloride molten salts, which has better corrosion resistance. The material has the advantages of low melting point, relatively stable under high temperatures, low viscosity, and low corrosiveness to 316L steel sheets, and is expected to be used in fields such as building energy saving and industrial waste heat utilization.

With the rapid development of nanotechnology, micro and nanometal materials have received much attention due to their unique physical and chemical properties. This paper aims to explore the size effect mechanism of the yield strength of micro and nano metal materials and establish the corresponding size effect model. We reveal the effect of grain size and interface effects on yield strength. The results show that by adjusting the composition and characteristic size of multilayers, metal multilayers can have a certain deformation ability while maintaining high strength.

This article introduces and validates a stealth metasurface that is compatible with visible, infrared, and microwave frequencies, designed to combine structural color for visible camouflage, low infrared emission, and extensive microwave absorption. The complete structure is constructed using two distinct layers: a visible-infrared layer (VIL) for coloration and infrared management, and a microwave absorption layer (MAL) for microwave absorption.. In the design of VIL, frequency selective surfaces (FSS) with SiO₂/Ag/ZnO/Ag multilayer film structures were designed to achieve selective reflection of visible light for multiple structural colors, low infrared radiation for infrared stealth, and high microwave transmittance simultaneously. For MAL, a synergistic approach of equivalent circuit method (ECM) and particle swarm optimization algorithm (PSO) is adopted to design and optimize square metasurfaces for 8-18GHz microwave absorption. Then the visible-infrared-microwave compatible stealth metasurface can be made by combining VIL and MAL. In conclusion, the metasurface structure presented in this article fulfills the requirements for multiband stealth in contemporary warfare and holds significant potential for widespread application.

In response to the issue of linear cutting of PMMA materials, this study conducted finite element simulations to model and calculate the linear cutting of PMMA targets using shaped charge liners made of copper and lead. Corresponding linear cutting experiments on PMMA targets were also carried out to investigate the influence of shaped charge liner materials on the linear cutting of PMMA. The research results indicate that the fracture of PMMA targets under the action of linear cutting with the cutting cord is mainly caused by jet penetration and spalling. The copper liner cutting cord exhibits superior jet penetration capability, approximately 28% higher than that of the lead liner under 0 mm standoff conditions. Additionally, after the action of the copper liner cutting cord, copper wire residues are produced, whereas no residue issue is observed with the lead liner cutting cord.

The number of fasteners used in aircraft is vast, reaching millions. Aluminum alloy wire for fasteners has become a focus of research. In this study, the Al-Zn-Mg-Cu alloy wire was prepared by hot rolling and extruding methods. A comparative analysis of microstructure and mechanical properties was examined. Results indicated that the hot rolling technique yields a more homogeneous microstructure and enhances the stability of mechanical properties. Following solution treatment and aging, a significant quantity of nano-sized strengthening η′ phases developed within the alloy. This led to improvements in both strength and elongation relative to the cold-deformed state. Consequently, the hot rolling method emerges as the most effective approach for the industrial production of alloy wire for fasteners.

Polypropylene (PP) is widely used in the automotive, packaging, and home appliance industries due to its excellent mechanical properties, chemical stability, and low cost. However, the low surface energy of PP substrates leads to poor adhesion strength between the substrate and polyurethane (PUR) coatings, limiting its potential in applications requiring high adhesion and durable coatings. To enhance the adhesion strength between PP substrates and PUR coatings, methods such as sandpaper abrasion, flame treatment, and surface treatment agents were investigated for their effects on the surface morphology of polypropylene composites. The wettability changes of PP substrate after different treatment methods were studied using a contact angle experiment. The adhesion of the coating on PP substrates was evaluated using the cross-cut test after applying these three surface treatment methods. The results indicated that the effectiveness of the treatments in improving adhesion strength, from strongest to weakest, was as follows: surface treatment agent = flame treatment > sandpaper abrasion.

In order to solve the shortcomings of poor mechanical properties of ceramic aerogels prepared by the sol-gel method in the market and the long-time consumption of the ceramic nanofiber aerogel (NFA) manufactured by the freeze-drying method, we adopted conjugate electrospinning and subsequent high-temperature calcination to realize the rapid preparation of ZrO₂-SiO₂ NFA under normal pressure. Influenced by the crystalline-amorphous structure inside of the single ZrO₂-SiO₂ ceramic nanofiber and the fluffy stacking among nanofibers, the ZrO₂-SiO₂ NFA can withstand 0.49 MPa tensile strength and be knotted like a rope. Moreover, the ZrO₂-SiO₂ NFA with a bulk density of 3.9 g cm^?3 shows a thermal conductivity of 0.024 Wm^?1 K^?1 and has great potential for application in high-temperature insulation.

Effects of homogenization on microstructures and properties of Mg-4Y-2.2Nd-0.4Zn-0.4Zr alloy were investigated by optical microscopy, X-ray diffractometry, and mechanical properties test. The results indicate that the cast alloy is mainly composed of the α-Mg phase, Mg₁₂Nd phase, Mg₂₄Y₅ phase, and Mg₁₂YZn phase. After homogenizing treatment, the Mg₁₂Nd phase, Mg₂₄Y₅ phase, and Mg₁₂YZn phases are dissolved into the grain interior. Increasing the homogenizing treatment temperature and prolonging the homogenizing treatment time can accelerate the homogenizing treatment process. The optimal homogenizing treatment process is 515°C × 8h. After homogenizing treatment, the dissolution of Y, Nd, and Zn elements significantly improves the properties of the test alloy, especially the tensile strength and elongation, whose value is increased from 192MPa and 6.2% in the cast state to 248MPa and 12.2% in the homogenized state.

To meet the welding requirements of SiCp/6061Al metal-matrix composites (MMCs), this paper proposed an additional ultrasonic treatment (AUT) based on traditional ultrasonic-assisted brazing. The shear strength of SiCp/6061Al MMCs brazed joints was effectively improved by a secondary ultrasonic treatment using Sn-Zn solder. Compared with the conventional ultrasonic treatment (43.84 MPa), the strength of the AUT welded joint was increased by 20 MPa, as high as 64.17 MPa. Moreover, through the analysis of the microstructure and fracture structure, the microstructure formation process of the weld during the AUT was found and expressed.

Submerged cavitating water jet (SCWJ) is widely concerned because of its green and large-area transient high-energy shock. However, there is rather little research on deeply revealing the complex flow field characteristics and realizing the micro-scale forming of metal foil arrays. Therefore, the present work aims to fully explore the axial and radial flow characteristics of submerged cavitating water jets and verify the feasibility of the proposed metal foil array micro-forming process. The results show that the cavitation cloud sheds periodically in the axial direction. When the incident pressure is 20 MPa, and the target distance is 120 mm, the cavitation collapse generates impact pressure, which presents three regions in the radial direction after shedding, including the jet impact area, cavitation impact area, and edge impact area. The 304 stainless steel foil forming trend is similar to the simulation showing an “M” shape, and the optimal forming area is the cavitation impact area with an outer diameter of 15.5 mm and inner diameter of 9 mm. Its average depth is 192.25 μm, the error is about ±2.5 μm, and the forming effect is more uniform.

Perovskite quantum dots (PQDs) hold immense potential for application in the subsequent LEDs because of their exceptional optoelectronic properties. Nevertheless, the presence of surface defects in PQDs leads to instability and leaves room for improvement. Therefore, this paper reports a ligand modification method that stabilizes CsPbBr₃ PQDs, with vinylphosphonic acid (VPA) serving as a functional ligand to regulate the nucleation and growth of PQDs during synthesis. PLQY reached as high as 81.8%. VPA also repairs surface defects on PQDs and enhances charge transport. The device brightness efficiency reached 13, 152 cd/m2. This strategy for ligand exchange maintained the dimensions and shape of CsPbBr₃ PQDs, while also improving the optical characteristics and electrical conductivity of CsPbBr₃ PQDs films. This work opens up a new pathway for achieving stable, high-performance LEDs using PQDs.

In response to solve the problem of a fractured spring in a safety valve of a nuclear power plant, a series of experiments were carried out, such as macroscopic inspection, chemical composition analysis, mechanical property test, metallographic examination, microscopic analysis and energy spectrum analysis, etc. The results show that the main cause of spring fracture is that the spring is in a corrosive environment with high material strength and hardness, which is sensitive to hydrogen. Eventually, environmental hydrogen embrittlement fracture occurs at the pitting corrosion site.

For the toughness testing of shipbuilding EH36 steel of different thicknesses, the Charpy impact test is generally used to assess resistance to unstable ductile fracture. However, for thick-walled steel plates, due to size limitations of the impact specimens, sampling can only be performed at specific locations, making it challenging to accurately measure the toughness of the entire thickness of the steel plate. In this experiment, low-alloy, high-strength EH36 steel of varying thicknesses was used to prepare compact tension (CT) specimens with a stepped notch. The results from the fracture toughness experiments indicated that the critical value of the stress intensity factor K_Q increases with the thickness of the EH36 plates. Due to the high plasticity of EH36, it was not possible to obtain the fracture toughness K_IC. The fatigue crack propagation tests demonstrated that the threshold values for fatigue crack propagation were similar across different thicknesses, ranging from 2.81 to 3.57 MPa·m^1/2. The cracks in the structure would not propagate below this range.

With the wide application of liquid metals in various fields, liquid metal embrittlement(LME) has been gradually recognized and emphasized by researchers. The grain boundary penetration mechanism is considered to be the most reasonable explanation for LME at present, but there is a lack of evidence to prove that the decrease in cohesion due to grain boundary penetration is the main factor for liquid metal embrittlement. In order to refine the grain boundary penetration mechanism, this paper performs LME of Ga-Al systems at different temperatures and observes the micro-morphology of pure aluminum specimens with different elongations after gallium embrittlement. The results show that gallium penetration leads to the reduction of intergranular cohesion and also hinders the dislocation motion, and the two together lead to gallium-to-aluminum liquid metal embrittlement.

Creep cavities constitute a quintessential form of creep degradation in P91 steel, serving as an indicator for evaluating the residual creep life. In this study, industrial CT was employed to examine the creep and tensile fracture surfaces of P91 steel specimens exhibiting both normal high hardness and anomalously low hardness, respectively, and the formation patterns of creep cavities were analyzed. It was discovered that a moderate increase in the number of scanning frames coupled with the implementation of beam hardening correction enhanced the quality of industrial CT images depicting creep cavities. Creep cavities, around 20 μm in size, were observed beneath the fibrous zone of the fracture samples; their genesis was attributed to the coalescence of micro-voids during the tertiary stage of creep. Specimens with high hardness presented a greater abundance of creep cavities compared to those with low hardness, whereas the latter exhibited more cavities than those generated by tensile processes. The elucidation of the formation patterns of creep cavities may provide technical support for the grading of aging in the microstructure of P91 steel.

We research the optimal design method of SiC_f/SiC ceramic matrix composite (CMC) turbine dovetail. Firstly, the geometrical shape optimization is carried out based on the multiscale damage analysis and the stress distribution characteristics of the turbine dovetail. The optimization results indicated a 31.8% improvement in the strength performance of the CMC dovetail. Then, considering the fibre distribution in the platform and dovetail regions, three corresponding lay-up design schemes were proposed. Based on the simulation results and performance preparation methods, the optimal lay-up scheme was determined. The experimental result showed the maximum tensile strength of the dovetail is 147.18 MPa, and the error is 5% compared with the simulation result, which indicates the accuracy of the optimized design method.

To address the issues of morphology defects and dimensional accuracy in the preparation of frequency selective surface (FSS) units using ultraviolet laser, experiments on laser process parameters are conducted on pure copper flat samples. First, single-factor experiments are performed on the pure copper flat sample. Based on the measurement results, the effects of four process parameters - namely, laser-on delay, laser-off delay, fill angle, and fill spacing - on the quality of unit morphology are analyzed to determine the optimized process parameters. The experimental results indicate that by optimizing the laser processing parameters, it is possible to address the “groov” defects caused by inappropriate delay parameters. Additionally, optimal fill angles ensure the consistency of unit dimensions, and employing unit size reverse compensation methods maintains consistency between processed dimensions and design dimensions. Finally, controlling the fill spacing results in different processing depths. The optimized process parameters are as follows: laser-on delay of 0.18 ms, laser-off delay of 0.12 ms, fill angle of 45°, after compensation size of 0.26 mm, and fill spacing of 1.5μm. By employing the optimized process parameters, rapid preparation of large-area, high-quality FSS units on the surface of pure copper flat plates can be achieved. The experimental method can provide a reference for other similar studies and practical applications.

The pigging operation of long-distance natural gas pipelines is a basic measure to ensure the safe, stable, and efficient operation of long-distance natural gas pipelines. A bolt broke and failed during the process of piping. To determine the specific cause of bolt failure, the failure bolts were analyzed by macroscopic inspection, chemical composition analysis, mechanical property test, metallographic analysis, and a scanning electron microscope. The results show that the chemical composition and tensile test of the bolts are not abnormal. The metallic structure of the failed bolt is tempered sorbite, and its grain size is 10.0 grade. According to the fracture morphology of the bolts, it is determined that fatigue failure is typical. The reason for the fracture is the difference in the preload degree of the bolts, which leads to the abnormal load on the part of the bolt and the initiation of small cracks near the tooth root of the thread. As the speed of the pig is not stable during operation, the larger vibration caused by the pig makes the crack begin to spread and eventually causes the bolt to break and fail.

B-type sleeve in-service welding repair technology is a permanent repair method for pipeline and leakage defects, and automatic welding technology has the characteristics of high efficiency, stable quality, and low requirements for operators. How to effectively use the advantages of both and improve the quality of in-service welding for pipeline maintenance and emergency repair has become an urgent problem that needs to be solved. The near-surface crack defect analysis of a type B sleeve fillet weld was started. The magnetic particle test confirmed a near-surface crack with a length of 10 mm, and the metallography test confirmed a depth of 2 mm. The cause was related to welding quality. Moreover, three unfused defects with a maximum length of 129 mm were found by phased array inspection. In addition, the welding quality of type B sleeve automatic welding was evaluated. It was found that the results of the guided bending and groove hammer-breaking test of the longitudinal weld were all wrong. The maximum hardness of the weld was higher than the requirements of general technical conditions.

This study investigates the surface modification of polyimide (PI) films using a 248 nm KrF excimer laser, focusing on the effects of laser parameters (such as energy density and pulse number) on the hydrophobic and hydrophilic properties of the material. By controlling the laser energy density (30-200 mJ/cm2) and pulse number (300-2100), the experiment analyzed the microstructure and wettability of the treated PI film surfaces. The results indicate that varying energy densities and pulse counts can significantly alter the surface roughness and chemical composition of PI, thereby affecting its wettability. Under the optimal conditions of 50 mJ/cm2 energy density and 2100 pulses, the PI films exhibited maximum hydrophobicity, as indicated by the highest contact angle. This enhancement in hydrophobicity is attributed to the formation of a carbon-rich layered surface structure induced by the laser treatment. Additionally, when the energy density was below 100 mJ/cm2, the contact angle increased with rising energy density but decreased when the energy density exceeded 100 mJ/cm2, due to surface ablation that damaged the carbon-rich layer. Similarly, an increase in pulse number promoted the formation of more chemical groups, enhancing hydrophobicity, but excessive pulses could damage the surface structure. These findings demonstrate that the surface microstructure and wettability of PI films can be effectively adjusted by optimizing the laser processing parameters, which provides new ideas and theoretical support for its application in microelectronics, biomedicine, and other fields.

To investigate the sensitivity of crack formation on the wear-resistant layer fabricated by overlaying welding on the guide slippers of coal cutters, finite-element method (FEM) simulations were used to predict the distributions of stress and deformation. The filler metal material used was DG09 steel, and its material properties, such as liquidus, solidus, thermal conductivity, and heat capacity, were imported into the FEM program. The FEM model was validated through the comparison of the distributions of microstructure and hardness obtained from experiments and simulations. The temperature field evolution was also studied, and it was observed that the temperature of an arbitrary point decreased with the increase in heat source distance. The deformation and stress distributions of the wear-resistant layer under different welding parameters were simulated. The simulation results indicate that increased heat input results in increased deformation and decreased stress. The welding tracks and arc extinguishing position showed higher deformation than other areas. Moreover, stress concentration was observed at the contact position of the weld pass. These findings provide valuable insights into eliminating crack formation during overlay welding.

The steel production process is a significant contributor to greenhouse gas emissions, particularly carbon dioxide. In response, steel enterprises have intensified efforts towards energy conservation and emission reduction. This study aims to construct a comprehensive model of the steel system and refine the objective function concerning carbon emissions through three key steps. Firstly, three metabolic concepts, collectively termed “BRL” metabolism, are delineated based on the primary metabolic traits of individual processes within the iron and steel industry. These include “B” metabolism, which sustains equipment operation through electricity provision; “R” metabolism, focusing on substance and energy processes at mechanical and chemical levels; and “L” metabolism, which represents total energy consumption minus “BR” metabolism. Secondly, by developing models for the material and energy consumption of each process, and leveraging an enhanced algorithm, the optimization process is refined to expedite achieving optimal outcomes, thereby reducing processing time. The results demonstrate a reduction in carbon emissions by 7.1%, alongside the production of 8.4 million tons of crude steel. Thirdly, this study analyzes the factors influencing “BRL” metabolism. These findings hold significant developmental implications for advancing energy conservation and emission reduction objectives within the iron and steel industry.

For pipelines served in a cold environment, low-temperature toughness was one vital element to ensure safety during serving, and drop-weight tear test(DWTT) is the common indicator to reflect the low-temperature toughness of pipeline steel. As we all know, there were many factors that influence low-temperature toughness, but studies were not sufficient regarding the effect of finishing cooling temperature. So, in this paper, the influence of finishing cooling temperature on low-temperature fracture toughness of pipeline steel was researched, and mechanical properties, microstructure, the fracture surface of DWTT samples, and grain boundary characteristics were observed and analyzed. After the same rolling treatment, three plates were cooled to 450°C, 500°C, and 550°C, respectively. The results showed that although three plates were cooled to different temperatures, the main type of microstructure remained the same, mainly quasi-polygonal ferrite and the small proportion of martensite-austenite islands, and average grain size gradually became smaller. When the finishing cooling temperature increased, the strength, including yield and tensile strength, climbed down, and sample 2 had the highest drop weight tear area of 92%, representing the highest low-temperature fracture toughness. The high-angle grain boundary densities of the three specimens were 0.413μm^?1, 0.738μm^?1 and 0.562μm^?1, respectively. On the whole, specimen 2 had the best low-temperature toughness. It was mainly because the high-angle grain boundary density of specimen 2 was the largest, and high-angle grain boundary density can prominently prohibit crack propagation and boost low-temperature fracture ductility.

In industrial production, it is difficult for us to obtain a large amount of fault data. To solve the problem of fault diagnosis with a small number of samples, we suggest a fault diagnosis method based on Deep Convolutional Generative Adversarial Networks (DCGAN) and the improved Swin transformer. This method uses DCGAN to expand fault samples and combine Swin Transformer to classify large images, achieving the recognition of fault states. From the experimental results, the method effectively addresses the challenges posed by uneven data, improving model generalization and fault diagnosis accuracy, and presenting a new way to detect faults in rolling bearings.

This paper investigates the FSW lap joining process for aluminum alloy castings used in the manufacturing of water boxes for new energy vehicles. Different process parameters were employed to join 6061 and A380 dissimilar aluminum alloy plates using friction stir lap welding, and the microstructure and mechanical characteristics of welds were investigated. Welding parameters included spindle speeds of 1500, 1800, and 2000 r/min and welder speeds of 500 and 600 mm/min. After welding, the appearance quality, metallographic structure, and microstructure were observed, and hardness tests and tensile shear tests were conducted. The findings demonstrated that at a welding speed of 500 mm/min, the grain size within the weld nugget zone initially decreased before subsequently increasing as the stirring head speed was raised. The hardness profile of the weld seam exhibited a W-shaped distribution, while the grain size during the nonlinear welding phase was typically finer than that in the linear stage. The research indicated that the weld’s overall quality peaked at a spindle speed of 1800 revolutions per minute and a welding speed of 500 millimeters per minute. From the perspective of quality optimization of an FSW welding pass made of cast aluminum alloy, the mechanical properties, macroscopic structure, and microscopic structure of the weld were used to select and optimize mixing process parameters, resulting in a feasible scheme for industrial production and application.

This paper studied the broken drive chain of an escalator reversal accident and discussed that the driving chain failure is the cause of the accident. At the same time, the failure mechanism of the escalator driving chain is analyzed. The research showed that the accident was mainly caused by fatigue fracture of the composite transition chain plate, which was due to the stress concentration effect at the bending corner. Also, reasonable countermeasures were put forward on the link structure selection, heat treatment process, and processing and assembly process of the driving chain.

This study aims to enhance the corrosion resistance of niobium (Nb)-containing ferritic stainless steel in urea environments within SCR systems. Through urea immersion corrosion tests, we found that as the Nb content increases, both the pitting depth and corrosion rate of the material significantly decrease. The study further revealed that the alkaline environment resulting from urea hydrolysis is the principal cause of stainless steel corrosion. The addition of Nb mitigated the formation of detrimental CrN and Cr₃C₂ compounds, and elevated the dissolved chromium Cr levels, thereby accelerating the regeneration of the passive film and diminishing the potential for galvanic reactions, ultimately improving the corrosion resistance of the stainless steel.

Duplex steel is highly regarded as a lightweight material for automotive structures due to its superior mechanical properties. In this study, the microstructural heritability and phase transformation behavior of DP780 high-strength steel plates were examined. The results demonstrated that the microstructures of hot-rolled plates were consistent across different orientations within the same section, while notable differences were observed between the edge and core regions. After cold rolling, the microstructure became elongated in the rolling direction, accompanied by a noticeable grain refinement. Similar to the mechanical performance of hot-rolled plates, cold-rolled plates exhibited superior properties at the edges compared to the core, further highlighting the heritability of microstructural characteristics. Furthermore, variations in phase microstructure for DP780 cold-rolled steel plates revealed that cooling rates of 5 °C/s and 10 °C/s were critical thresholds. At these rates, significant shifts in phase microstructure changes were observed. These findings underscore the importance of precise control over process parameters, particularly at lower cooling rates, to ensure the stability of microstructure and mechanical properties during production.

Additive manufacturing parts are widely used in industries such as aerospace, medical, and automotive due to their unique forming methods, which have the advantages of high material utilization, fast forming speed, and the ability to form complex parts. However, its process characteristics can easily lead to the occurrence of internal and external defects, which can affect the fatigue performance of metal materials. With the continuous improvement of comprehensive performance requirements such as material strength, wear resistance, and corrosion resistance in the aerospace field, aluminum matrix composites based on aluminum and its lightweight high-strength alloy materials gradually attract the attention of scholars. This paper takes aluminum matrix composites reinforced with nanoparticles as the research object and completes the manufacturing of test pieces with different printing directions through SLM additive manufacturing. CFQ_base value tests are conducted to study their fatigue performance. The experimental results indicate that there is not much difference in fatigue performance between the X-Y and Z directions. The fracture analysis of the sample shows that there are obvious holes or irregular planes on the surface of the test piece.

This study examines the influence of retained ferrite on the hydrogen embrittlement resistance of medium-carbon steel processed via rapid induction heat treatment, in comparison to tubular furnace treatment. Microstructural analysis indicates that samples subjected to rapid induction heating retain approximately 10% ferrite, while those treated in the tubular furnace are primarily martensitic. The former exhibits superior resistance to hydrogen embrittlement, with minimal strength and ductility loss after short hydrogen charging. This improvement is attributed to ferrite’s role in providing irreversible hydrogen traps and alleviating residual stresses within tempered martensite. The fractographic analysis further confirms a shift from ductile to brittle fracture under prolonged hydrogen exposure, underscoring ferrite’s beneficial effect in mitigating embrittlement.

A detailed study is conducted on the high-temperature wear performance of valve seat rings with different Ni contents. The wear resistance of two types of contact pairs is studied through methods such as three-dimensional profile, wear amount, and wear morphology. Research has shown that the friction coefficients of both contact pairs gradually decrease with increasing temperature, while the wear amount of both contact pairs shows a trend of first decreasing and then increasing, and both have the lowest wear amount under 500? conditions. The wear performance of Inconel 751 material contact pairs is better at room temperature, but Pyromet 31 material contact pairs have stronger stability under high-temperature conditions. Therefore, Pyromet 31 material has better wear and wear resistance in high-temperature environments. Temperature can affect the hardness of materials, resulting in varying degrees of material softening, and also affect the formation rate of oxide films on wear surfaces. The rapid formation of oxide films is an important reason for the greater wear resistance of Pyromet 31 materials.

3D-printed continuous carbon fibre-reinforced polymers (C-CFRPs) often suffer from higher porosity than conventionally manufactured composites. Here, the volume, distribution, and morphology of defects in 3D-printed C-CFRPs were investigated using X-ray computed tomography. The defects were automatically segmented based on the U-Net deep learning neural network and quantitatively analyzed. The defects are periodically distributed following the laminar structure, featuring ellipsoidal and net-like shapes. The long axes of the ellipsoidal-shaped pores are found to be generally aligned along the fibre direction in each layer, and these pores are more elongated in the top layer than in the bottom layer.

This study investigates the defect evolution mechanisms in nickel-based GH4169 superalloy fabricated using selective laser melting (SLM) under high-temperature fatigue. X-ray computed tomography (CT) was employed for three-dimensional defect characterization, and in-situ fatigue tests were conducted at 400°C. Initial defects were found to be randomly distributed, primarily consisting of pores and lack-of-fusion (LOF) defects, with 80% having an equivalent diameter smaller than 20 μm. Pores exhibited significant axial elongation during fatigue loading in stress-concentration regions, especially at elevated temperatures, where localized plastic deformation was enhanced. Additionally, fatigue cycling led to defect coalescence, with smaller defects merging into larger ones, primarily along the tensile loading direction.

It is important to consider the potential damage caused by fretting wear to bearings in wind power equipment. This paper presents a detailed investigation into the impact of load on the fretting wear characteristics of GCr15 bainite-bearing steel under dry friction conditions. The findings indicate that as the normal load increases, the fretting operating state of the test steel transitions from a complete slip zone to a mixed zone, accompanied by a gradual decline in the friction coefficient. As the load was increased from 10 N to 100 N, the wear volume demonstrated a corresponding increase. However, when the load is increased to 130N, the critical value is reached, resulting in a significant reduction in wear volume. At a normal load of 10N, 40N, and 70N, the predominant wear mechanism is abrasive. At a load of 100N, adhesive wear is observed primarily in the center of the wear scar. Abrasive wear is primarily evident at the edge of the scar. At a load of 130N, the wear mechanism transforms, with the emergence of additional mechanisms, namely compaction and cold welding, in addition to the original wear mechanism. Furthermore, oxidative wear was observed in all test steels to varying degrees.

Pipeline steels are usually applied to oil and gas transportation over long ranges. Because of its served environment with wet H₂S, cracks caused by hydrogen are most likely to be huge potential invalidity threats during the served life. The cooling techniques can significantly affect the micro structure, the mechanical properties, and the ability to hinder cracks in the pipeline steel. Therefore, it was necessary to research the influence of finishing cooling temperature on cracks caused by hydrogen of pipeline steel. So, in the study, concerning microstructure, the scattering condition of high angle grain boundaries and dislocation, as well as the effect of finishing cooling temperature on cracks caused by hydrogen of pipeline steel, were studied. The discoveries showed that among the three finishing cooling temperatures, such as 650 °C (Specimen 1), 550 °C (Specimen 2), and 450 °C (Specimen 3), Specimen 2 had the highest proportion of HAGB, with 48.0%. HAGB can effectively promote crack deflection during crack propagation and hinder the crack’s extension. Also, its lower dislocation density can produce excellent hydrogen-induced cracking performance for pipeline steel. Overall, when the finishing cooling temperature is 550°C (Specimen 2), steel can have the best hydrogen-induced cracking resistance performance.

Deform-3D software was used to analyse the forming characteristics of wear-resistant steel balls, material fluidity, stress-strain distribution, load-time curve, and break coefficient of three kinds of forging billets in the forging process. It was concluded that with the reduction of the height of the original billet, the damage coefficient of the middle position of the billet decreased during the final stage of billet forming. The forging ratio of the blank should be appropriately reduced to reduce the risk of forming defects in the forging process.

To solve the problems in high-quality aluminum alloy profile production, we examined the three groups from different process values on the effect of product structure and mechanical properties. This kind of profile is extrusion production, and with the common civil building doors and Windows hollow profile as the research objects, the extrusion process, the structure design of double-hole plane split, and the extrusion problem are studied in detail.

Employing univariate analyses, the irradiation energy, scanning speed, and particulate delivery pace are systematically varied to assess the influence of these process variables on the integrity and microstructure of the Colmonoy88 ceramic particle-reinforced nickel-based alloy’s fused overlay. The findings indicate that augmenting the irradiation energy and diminishing the traversal velocity are effective in mitigating the cracking propensity of the overlay. Additionally, within an optimal range, elevating the particulate delivery pace can also contribute to a reduction in the cracking propensity. Optimal conditions are identified at an irradiation energy of 2500 W, a scanning speed of 60 mm/s, and a particulate delivery pace of 45 g/min.

Material, dust content, temperature, water, and other factors were studied in the performance of asphalt surface treatment. Results show that asphalt surface treatment performance varied with material types and temperature. The loss of the aggregate percentage increases with dust content. Precoated aggregate effectively improves the performance of asphalt surface treatment. Temperature has a positive influence on the performance of asphalt surface treatment. The aggregate residual rate of asphalt surface treatment decreased with the increase in immersion time.

Gears are widely used and important components in mechanical equipment for connecting and transmitting power. The main forms of gear failure include fracture, peeling, wear, and cracks. Among them, gear fracture often causes system or machine failure, which may lead to major safety accidents in particularly serious situations. The identification and judgment of gear failure characteristics is the fundamental and critical step in identifying the causes of gear failure and proposing preventive measures. This article focuses on the most harmful gear fracture, elaborating on the basic characteristics related to fracture failure modes and the characteristics related to causes. It explores the strategies for detecting and analyzing typical failure characteristics of gears, aiming to promote the development of gear fracture failure analysis and prevention, and provide a reference for the design, manufacturing, use, and maintenance of gears.

The safety issue is one of the key factors limiting electrical vehicles application. The microstructure and chemical structure of battery electrodes are investigated to figure out the thermal runaway behavior characteristics of aged batteries. Taking 2.1 Ah 18650 Li(Co, Mn) cylindrical batteries (Xinquan Energy Technology Co., Ltd., China) as examples, cycling tests operated in high temperatures are developed. After 200 cycles operated at 80°C, the Li(Ni₅Co₃Mn₂) Batteries are prepared as 10% degrading batteries and failure batteries. X-ray Photoelectron Spectrum (XPS) is applied to investigate the impacts of high temperature on the aging of Li(Ni₅Co₃Mn₂) Batteries. The surface material change observed on the surface of the electrode affected by excessive temperature, 80°C, is the deposition of the lithium salt produced by the reaction between lithium ion and electrolyte, causing the loss of active lithium material. With the deposition of the lithium salt on the surface of the electrode, the capacity fades of Li(Ni₅Co₃Mn₂) batteries are accelerated and the stabilities of batteries are decreased. The combustion tests are conducted on the reference batteries, aged batteries, and failure batteries to clarify the relationship between the surface chemical change of the electrode and the thermal runaway behavior of aged batteries. Utilizing the data that comes from the battery combustion tests, the stability of aged batteries is studied by comparison analysis of flame height and heat release rate (HRR).