2025,Volume 54, Issue 1

>2025 Invited Manuscripts for Young Editorial Board

• Characteristics of Transition Layer at Soft Metal-Substrate Interface for Metal Seal

  Zhang Dawei, Zhang Xuekai, Cao Zixuan, Ge Ziyi, Lv Shichang, Li Zhijun, Zhao Shengdun, Hu Yanghu

  2025,54(1):1-9 DOI: 10.12442/j.issn.1002-185X.20240473

  Abstract(97) HTML(79) PDF(3.09 M)( 97)

  Abstract:The pressure-actuated metal seal with soft metal coating has been widely used in complex working conditions such as high temperature, low temperature and high pressure. The investigation of the characteristics and binding strength of the transition layer between the soft metal coating and the superalloy substrate is important to improve the sealing performance and to model and simplify the working through-process of metal sealing. The distribution characteristics of elements at soft metal-substrate interface and the binding strength between coating and substrate under different thicknesses and material combinations of coating layer were studied by experimental methods. The results indicate that the thickness of soft metal coating has little influence on the interface morphology of GH4169-Cu, GH4169-Ag and Cu-Ag, but has an influence on the thickness of transition layer between different metals, while this influence is weakened with increasing the coating thickness, and the thickness of transition layer is about 2 μm when the coating thickness is more than 30 μm. The cross-cut test shows that the Cu, Ag and Cu-Ag coatings are all well combined with nickel-based superalloy GH4169 substrate. The materials of soft metal, i.e. the coating materials, have significant influence on the characteristic of transition layer and the surface characteristics of coating after cross-cut test.

• Effect of Co Content on Microstructure and Mechanical Properties of High-Entropy High-Temperature Shape Me-mory Alloy

  Zhao Yanchun, Jin Bo, Feng Yuanfei, Ma Huwen, Yu Zhiqi, Feng Li, K Liaw Peter

  2025,54(1):10-16 DOI: 10.12442/j.issn.1002-185X.20240507

  Abstract(16) HTML(57) PDF(2.58 M)( 57)

  Abstract:(TiZrHf)₅₀Ni₃₀Cu_20-xCo_x (x=2, 4, 6, at%) high-entropy high-temperature shape memory alloys were fabricated by water-cooled copper crucible in a magnetic levitation vacuum melting furnace, and the effects of Co content on microstructure and mechanical properties were investigated. The results indicate that the grain size of the alloy decreases with increasing the Co content. In the as-cast state, the alloy consists primarily of the B19′ phase, with a trace of B2 phase. The fracture morphology is predominantly composed of the B19′ phase, whereas the B2 phase is nearly absent. Increasing the Co content or reducing the sample dimensions (d) markedly enhance the compressive strength and ductility of the alloy. When d=2 mm, the (TiZrHf)₅₀Ni₃₀Cu₁₄Co₆ alloy demonstrates the optimal mechanical properties, achieving a compressive strength of 2142.39±1.8 MPa and a plasticity of 17.31±0.3%. The compressive cyclic test shows that with increasing the compressive strain, the residual strain of the (TiZrHf)₅₀Ni₃₀Cu₁₄Co₆ alloy increases while the recovery ability declines. The superelastic recovery capability of the alloy is continuously enhanced. The superelastic recovery rate increases from 1.36% to 2.12%, the residual strain rate rises from 1.79% to 5.52%, the elastic recovery rate ascends from 3.86% to 7.36%, while the total recovery rate declines from 74.48% to 63.20%.

• Graphene Size Dependent Hardness and Strengthening Mechanisms of Cu/Graphene Composites:A Molecular Dynamics Study

  Zhang Shuang, Chang Guo, Li Liang, Li Xiang, Peng Haoran, Chen Kaiyun, Yang Nan, Huo Wangtu

  2025,54(1):17-26 DOI: 10.12442/j.issn.1002-185X.20240513

  Abstract(15) HTML(34) PDF(1.86 M)( 64)

  Abstract:The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size, distribution and morphology of graphene. However, the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated. Herein, under the same volume fraction and distribution conditions of graphene, molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field. Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison. The results show that the strengthening effect changes with varying the graphene sheet size. Besides the graphene dislocation blocking effect and the load-bearing effect, the deformation mechanisms change from stacking fault tetrahedron, dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size. The hardness of Cu/graphene composite, with the graphene sheet not completely covering the metal matrix, can even be higher than that of the fully covered composite. The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.

• Microstructure Analysis of TC4/Al 6063/Al 7075 Explosive Welded Composite Plate via Multi-scale Simulation and Experiment

  Zhou Jianan, Luo Ning, Liang Hanliang, Chen Jinhua, Liu Zhibing, Zhou Xiaohong

  2025,54(1):27-38 DOI: 10.12442/j.issn.1002-185X.20240504

  Abstract(9) HTML(25) PDF(3.62 M)( 46)

  Abstract:Because of the challenge of compounding lightweight, high-strength Ti/Al alloys due to their considerable disparity in properties, Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding. The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction (EBSD). A methodology combining finite element method-smoothed particle hydrodynamics (FEM-SPH) and molecular dynamics (MD) was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale. The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration, without discernible defects or cracks. The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces. Furthermore, the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer. The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results. MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase, and the simulated thickness of interfacial diffusion aligns well with experimental outcomes. The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates. Furthermore, this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.

• Effect of Aging Treatment on Properties and Post-weld Microstructure of Stainless Steel Containing Niobium

  Liu Tianzeng, Zhao Yanchun, Chen Anzhong, Yu Zhiqi, Feng Li, Li Jucang, Pan Jixiang

  2025,54(1):39-49 DOI: 10.12442/j.issn.1002-185X.20240506

  Abstract(3) HTML(23) PDF(4.47 M)( 38)

  Abstract:The effects of different aging processes on the precipitated phase, mechanical properties, molten salt corrosion resistance and post-weld microstructure of 347H stainless steel were studied. The results show that a large number of precipitated phases appear in the crystal after aging at 700 °C for 400 h. After aging for 3000 h, the number of precipitated phases increases and most of them are gathered at the grain boundaries. There are two forms of precipitates, one is the coarse precipitate rich in Cr, and the other is the smaller precipitates mainly consisting of NbC. After aging at 700 °C for 30 min, the yield strength and tensile strength of the samples at room temperature and 593 °C increase, but the elongation decreases. The corrosion results in nitrate at 565 °C show that the corrosion products of the aged samples are the same as that of the original samples, which are Fe₂O₃, Fe₃O₄, MgCr₂O₄, MgFe₂O₄, FeCr₂O₄ and NaFeO₂. The proportion of Fe₃O₄ that is dense and well bonded to the subtrate in the original sample is higher than that in the aged sample, so the corrosion resistance is better. At 700 °C, the aging time has no obvious effect on the microstructure after welding.

• Effects of Cerium-Rich Rare Earth and Al-Ti-B Composite Addition on Microstructure and Mechanical Properties of Al-Mg-Si Alloys

  Chong Yufan, Du Zhaoxin, Gong Tianhao, Sun Baoan, Pan Zheru, Qi Lele, Xie Chengcheng, Cheng Jun

  2025,54(1):50-61 DOI: 10.12442/j.issn.1002-185X.20240427

  Abstract(7) HTML(22) PDF(6.08 M)( 38)

  Abstract:Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B. Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably promotes the refinement of the alloy's grains. Ce and La elements are combined with Si and other elements to form rare earth phases, improving the morphology and distribution of precipitates and mitigating the adverse effects of β-Fe phases on the microstructure and mechanical properties of alloy. However, excessive rare earth content poses challenges; it not only leads to a decrease in Mg-Si strengthening phase by binding with Si but also promotes the formation of larger or numerous rare earth phases that may act as initiation points for cracks, thereby impeding the improvement of the structure and performance of alloy. The composite addition of cerium-rich rare earths and Al-Ti-B not only preserves the strength of the alloy but also significantly enhances the plasticity of the 6061 as-cast alloy. At a composite addition ratio of Al-Ti-B:RE=2:1, the newly developed 6061-RE aluminum alloy exhibits increased average elongation by 50% and 45% in its as-cast and homogenized states, respectively, compared to the baseline 6061 alloy, facilitating subsequent deformation processing. After solution treatment at 540 °C for 1 h and aging at 180 °C for 5 h, the average ultimate tensile strength and yield strength of 6061-RE alloys reach 313.2 and 283.1 MPa, increased by 12.3% and 14.5% compared with those of the original alloy, respectively, and the average elongation is improved by 41%.

• Early Crack Propagation Behavior of Laser Metal Deposited Ti-6Al-4V Alloy Under High Cycles Fatigue Loading

  Li Yanping, Huang Wei, He Yan, Xu Feng, Zhao Sihan, Guo Weiguo

  2025,54(1):62-75 DOI: 10.12442/j.issn.1002-185X.20240580

  Abstract(11) HTML(27) PDF(4.49 M)( 42)

  Abstract:The crack initiation and early propagation are of great significance to the overall fatigue life of material. In order to investigate the anisotropic fracture behavior of laser metal deposited Ti-6Al-4V alloy (LMD Ti64) during the early stage, the four-point bending fatigue test was carried out on specimens of three different directions, as well as the forged specimens. The results indicate the anisotropic crack initiation and early propagation of LMD Ti64. The direction perpendicular to the deposition direction exhibits a better fatigue resistance than the other two. The crack initiation position and propagation path are dominated by the microstructure in the vicinity of U-notch. LMD Ti64 has a typical small crack effect, and the early crack propagation velocities in three directions are similar. Affected by the slip system of LMD Ti64, secondary cracks frequently occur, which are often found to have an angle of 60° to the main crack. The electron backscatter diffraction analysis indicates that LMD Ti64 has preferred orientations, i.e., strong //Z texture and //Z texture. Their crystallographic orientation will change as the direction of columnar β grains turns over, resulting in the fatigue anisotropy of LMD Ti64 in crack initiation and early crack propagation process.

• Effect of SiO₂ Nanoparticles/Silicate on Characteristics of Micro-arc Oxidation Coating Formed on TC4 Alloy

  Sun Fengyu, Yang Zhao, Hu Jie, Gong Yunbai, Wang Ping, Luo Qiming, Zhu Manlan

  2025,54(1):76-83 DOI: 10.12442/j.issn.1002-185X.20240394

  Abstract(6) HTML(21) PDF(2.70 M)( 34)

  Abstract:TC4 micro-arc oxidation (MAO) coatings were prepared by adding SiO₂ nanoparticles or sodium silicate to the sodium meta-aluminate-based electrolyte. The effect of additives was investigated by XRD, SEM, EDS, electrochemical and wear tests. The results show that additives can considerably accelerate the formation of MAO coatings. The coatings are mostly composed of rutile and anatase TiO₂, α-Al₂O₃, γ-Al₂O₃, Al₂TiO₅ and SiO₂. Sodium silicate and SiO₂ nanoparticles added to the coating can effectively reduce the size of micropores and increase its thickness, whereas SiO₂ nanoparticles with superior physical properties can be directly deposited at the discharge channel, significantly increasing the coating's resistance to wear and corrosion. The coating with SiO₂ nanoparticles exhibits the best overall performance, with the lowest corrosion rate and average friction coefficient of 4.095×10^-5 mm/a and 0.30, respectively.

• Advancement in Tungsten/Molybdenum Alloy Welding Tech-nology

  Wang Xingxing, Chu Haoqiang, Xie Xu, Pan Kunming, Du Quanbin, Li Ang, Zhang Liyan

  2025,54(1):94-108 DOI: 10.12442/j.issn.1002-185X.20240462

  Abstract(10) HTML(22) PDF(2.56 M)( 51)

  Abstract:Tungsten/molybdenum alloys are widely utilized in the nuclear industry, aerospace and various other fields due to their high melting points and strength characteristics. However, poor sinterability and processability make it difficult to manufacture large-size or complex-shaped parts. Hence, an in-depth study on the welding technology of tungsten/molybdenum alloys is urgent. An introduction of tungsten/molybdenum alloy welding defects and joining process was provided, along with recent advancements in brazing, spark plasma sintering diffusion bonding, electron beam welding and laser beam welding. The latest progress in alloy doping treatment applied to tungsten/molybdenum alloy dissimilar welding was also discussed, and existing welding problems were pointed out. The development prospects of weldability of tungsten/molybdenum alloy by various joining technologies were forecasted, thereby furnishing a theoretical and practical found.

• Effects of Si on Stress Corrosion Cracking Properties of Austenitic Stainless Steel

  Gong Weijia, Chen Shuai, Liu Lupeng, Du Donghai

  2025,54(1):109-117 DOI: 10.12442/j.issn.1002-185X.20240516

  Abstract(4) HTML(21) PDF(8.56 M)( 38)

  Abstract:Irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steel in reactor core is one of the most important factors affecting the safety and lifetime of nuclear reactor. Numerous studies have shown that IASCC of austenitic stainless steel is related to irradiation-induced Si enrichment at grain boundary. To explore the influence of Si enrichment at grain boundary on the stress corrosion cracking rate of austenitic stainless steel, the crack growth rate (CGR) of model alloys with different Si contents in water at 320 ℃ was measured, and the crack propagation paths and fracture morphologies were analyzed. Results show that CGR of Si-containing alloy is higher in the oxygenated water environment, showing no obvious dependence on Si content; while in the hydrogenated water environment, CGR is increased with the increase in Si content and reaches the level in the oxygenated water environment. Stress corrosion cracks mainly propagate along large-angle grain boundaries, and the higher the Si content, the sharper the crack tips. The oxide film generated by oxidation of enriched Si at grain boundary in high-temperature water is easily soluble in water, resulting in a decreased strength of the grain boundary oxide film, which is more likely to crack under stress, and leading to an increased sensitivity to stress corrosion cracking.

• Effect of W Replacing Part of Mo on Wear Resistance and Tensile Property of Ti-Al-Mn-Mo Alloy

  Yang Xinyue, Li Xiaobing, Xue Peng, Chen Bo, Shu Lei, Niu Hongzhi, Liu Kui

  2025,54(1):118-125 DOI: 10.12442/j.issn.1002-185X.20230700

  Abstract(10) HTML(22) PDF(4.33 M)( 41)

  Abstract:The wear resistance and tensile property of two low-cost, easy-to-deform Ti-44Al-3Mn-0.8Mo (TMM) and Ti-44Al-3Mn-0.4Mo-0.4W(TMMW) alloys (atomic fraction, %, the same below) were comparatively tested. The effects of replacing 0.8 Mo with 0.4Mo-0.4W on their wear resistance, microhardness, tensile property and microstructure were analyzed. The results show that replacing part of Mo with W can obviously improve the wear resistance and microhardness of Ti-Al-Mn-Mo alloy, and also increase the tensile strength of the alloy at room temperature and high temperature. The room temperature elongation is increased from 0.75% to 1.50%, while the high temperature elongation is slightly reduced. It is found that the β-stabilizing effect of W in the alloys is slightly weaker than that of Mo, and the replacement of W reduces the content of β_o phase and γ phase remaining in the structure, increases the content of α₂ phase obviously, increases the content of lamellar structure, and decreases the lamellar spacing. The higher microhardness and better wear resistance of TMMW alloy are closely related to the changes of microstructure and phase composition. The decrease in β_o phase content, the increase in lamellar content and the decrease in lamellar thickness are the main reasons for the higher tensile strength and better room temperature elongation of the alloy after W replaces part of Mo.

• Effect of Strut Diameter Difference of bcc Lattice Structure of 316L Stainless Steel Prepared by Selective Laser Melting on Compression Performance

  Wang Jiandong, Guan Yao, Yang Jinshui, Wang Dapeng, Dou Wenhao

  2025,54(1):126-133 DOI: 10.12442/j.issn.1002-185X.20240559

  Abstract(11) HTML(24) PDF(5.27 M)( 47)

  Abstract:In order to study the effect of strut diameter difference on the compression performance of body-centered cubic (bcc) lattice structure, five bcc-x lattice structures with different strut diameters were designed under the same density. 316L stainless steel with bcc-x lattice structures were fabricated by selective laser melting technique. A finite element analysis model of quasi-static compression of the lattice structure was established using the plastic constitutive model of the material. The experimental and finite element simulation results show that with the increase in strut scale factor x, the compressive performance of bcc lattice shows a trend of first increasing and then decreasing, and when x is greater than 1, the compressive performance is more sensitive to x. When x is equal to 1, the optimal compressive properties can be obtained. The specific stiffness, specific strength and specific energy absorption of bcc-1 are 986.794 MPa·cm³·g^-1, 25.084 MPa·cm³·g^-1 and 11.731 J/g, respectively. Compared with bcc-1, both the decrease and increase of x will destroy the axial symmetry of the cell, and the larger the x deviating from 1, the more irregular the distribution of high stress regions between layers, and the more unstable the deformation of the structure. The compressive performance of bcc-1.5 is the worst, and the specific stiffness, specific strength and specific energy absorption are reduced by 20.765%, 12.265% and 12.309%, respectively, compared with those of bcc-1.

• Numerical Calculation Study on Interfacial Microstructure Characteristics of Multilayer Metal Composite Materials

  Liang Hanliang, Luo Ning, Zhou Jianan, Chen Jinhua, Jia Yongsheng, Chen Xiang

  2025,54(1):134-146 DOI: 10.12442/j.issn.1002-185X.20240542

  Abstract(10) HTML(27) PDF(7.36 M)( 44)

  Abstract:With the rapid progress and development of technique and equipment in the field of aerospace and weapon protection, it is of great significance to accelerate the development and research of new metal composite materials with lightweight and high-strength properties. In this research, the multiscale numerical calculation method was used to explore the variation law of interface characteristic parameters as well as atomic-scale diffusion behavior and characteristics of the interface of explosive welded multilayer metal composite materials. The results show that with the passage of time, the dynamic collision angle increases slightly in the initial stage and remains stable in the middle stage. The joining interface shows obvious waveform structure characteristics. The pressure distributed at the joining interface of the multilayer composite sheet is significantly higher than that in other regions of the sheet, and the pressure of the bonding interfaces decreases gradually from top to bottom. The effective plastic strain at the bottom interface is slightly higher than that at the other three interfaces. Under microscale collisions at different speeds, obvious atomic diffusion occurs at all three solder joints. As the impact speed decreases, the thickness of the atomic diffusion layer at the interface also decreases. The thickness of the three diffusion layers ranges from 1.12 μm to 1.58 μm, 1.8 μm to 2.55 μm and 1.22 μm to 1.73 μm.

• Microstructure and Properties of Laser Welded Joints of New Ti-Al-Cr-Mo-Zr Titanium Alloy Welding Wire

  Fang Naiwen, Feng Zhiqiang, Wu Pengbo, Huang Ruisheng, Luo Jiutian, Li Quan, Xin Guosong

  2025,54(1):147-155 DOI: 10.12442/j.issn.1002-185X.20240536

  Abstract(7) HTML(21) PDF(5.42 M)( 38)

  Abstract:Titanium alloy solid welding wire was developed by optimizing the synergistic mechanism of Cr-Mo-Zr. The liquid bridge transition with uniform droplet stress and stable droplet transition was selected for laser wire filling welding. Finally, the high quality welding of 20 mm thick Ti64 titanium alloy plate was realized. Results show that Ti-Al-Cr-Mo-Zr titanium alloy solid welding wire has enough stiffness and relaxation, which provides a guarantee for the accurate alignment between the beam and the welding wire, and stable wire feed during the subsequent laser wire filling welding. In the welded seam, the proportion of large-angle grain boundaries greater than 10° is 97.8%, the geometrically necessary dislocation density is low, and the proportion of small size grains is relatively large. The overall orientation of the welded seam is not strong, the texture is not obvious and the distribution is random, and the maximum multiples of uniform distribution is only 12.66. The average tensile strength of welded joints is 901 MPa, the average elongation is 21%, and the impact toughness at room temperature ranges from 29 J to 33 J. The self-developed and designed Ti-Al-Cr-Mo-Zr titanium alloy solid welding wire plays an important role in obtaining welded joints with synergistic optimization of strength and plasticity-toughness, and provides basic technical support for the long-term safe service of titanium alloy welding structures.

• Numerical Simulation and Experimental Research on Plasma Welding of Shift Fork Shaft

  Yang Jianguang, Ji Hongchao, Pei Weichi, He Lei, Huang Xiaomin, Wang Shanshan

  2025,54(1):156-170 DOI: 10.12442/j.issn.1002-185X.20240373

  Abstract(17) HTML(24) PDF(7.91 M)( 41)

  Abstract:The shift fork shaft is an important component in manual transmission, automatic manual transmission and dual-clutch transmission to connect the fork and adjust gear engagement. To study the relationship among welding deformation, residual stress and welding process parameters during plasma welding of shift fork shaft, based on ABAQUS simulation software, the temperature-displacement coupled finite element calculation method was adopted and double ellipsoidal heat source model was selected to numerically simulate the stress field, deformation and temperature field of the welded plate and shift fork shaft. The optimization of the welding process of shift fork shaft was completed, and the reliability of the optimized model was verified through simulation and experiments. The results show that welding deformation is decreased with the increase in welding speed. The welding deformation is relatively small at welding speed of 2.5–3.0 mm/s and is increased with the increase in welding current. The welding residual stress does not show a significant variation law with welding current and welding speed, but the peak values are distributed around 560 MPa, which is smaller than the tensile strength of the fork shaft (650 MPa), and there is a local stress concentration phenomenon. Overall, residual stress is mainly distributed at both ends of the weld seam, and deformation mainly occurs at the weld plate. The optimized model has a more balanced peak temperature of the two weld heat sources, and local welding residual stress and deformation slightly decrease. Therefore, simulation and experimental results can provide theoretical guidance for the control of welding quality in actual production process.

• Effect of Sn and Mn Composite Addition on Microstructure and Properties of Micro-arc Oxidation Coating on AZ21 Alloy

  Gao Fuhao, Lv Binjiang, Guo Feng, Cui Ning, Xu Tiewei

  2025,54(1):171-183 DOI: 10.12442/j.issn.1002-185X.20240304

  Abstract(8) HTML(15) PDF(10.55 M)( 40)

  Abstract:The effects of low-cost Sn (1wt%) and Mn (0.5wt%) composite addition on the microstructure and properties of micro-arc oxidation coatings on extruded Mg-2Al-Zn (AZ21) alloy were studied. After the addition of Sn and Mn elements to the substrate, the phase composition of the coatings remains unchanged, mainly consisting of MgO, MgAl₂O₄ and AlPO₄ phases. The thickness and porosity of the coatings increase slightly, the thickness increases from 8.49 μm to 9.60 μm, and the porosity increases from 5.05% to 5.75%. The wear resistance and corrosion resistance of the substrates and coatings were evaluated by dry friction and wear test, immersion test and potentiodynamic polarization test. The results show that the micro-arc oxidation coating significantly improves the wear resistance and corrosion resistance of the substrate. The composite addition of Sn and Mn improves the wear resistance of the coatings, but their corrosion resistance decreases. The wear rate of the coating decreases from 3.53×10^-5 mm³·(N·m)^-1 to 2.993×10^-5 mm³·(N·m)^-1. The corrosion current density of the coating increases from 3.14×10^-6 A·cm^-2 to 4.18×10^-6 A·cm^-2.

• Hot Deformation Behavior of High-Ductility Mg-1.92Zn-0.34Y Alloy with Nano-quasicrystals

  Zeng Qi, Wang Shaoyang, Rong Peng, Zhu Kai, Zhang Yingbo, Gao Chuanyun, Hu Yunfeng

  2025,54(1):184-190 DOI: 10.12442/j.issn.1002-185X.20240443

  Abstract(4) HTML(15) PDF(3.76 M)( 35)

  Abstract:The nano-quasicrystal reinforced Mg-Zn-Y alloy has ultra-high elongation at room temperature and has broad application prospects. It is necessary to further study its hot deformation behavior to provide a theoretical and application basis for subsequent processing. In this research, Mg-1.92Zn-0.34Y (wt%) alloy containing nano-quasicrystalline particles was prepared by semi-solid and hot extrusion composite process. The high temperature deformation mechanism of the alloy at temperatures of 250, 300 and 350 ℃ and strain rates of 10^-3, 10^-2 and 10^-1 s^-1 was investigated. The effect of nano-quasicrystal particles on hot deformation behavior of Mg-1.92Zn-0.34Y alloy was studied. The results show that the high-ductility Mg-1.92Zn-0.34Y alloy with nano-quasicrystals can be prepared by the combination process of semi-solid and hot extrusion. The processed alloy exhibits a high tensile elongation to failure (EL) of 44%±2.6%, ultimate tensile strength (UTS) of 258±2.0 MPa and yield strength (YS) of 176±1.6 MPa at room temperature. The average deformation activation energy and stress index of Mg-1.92Zn-0.34Y alloy according to the constitutive equation are 271.7812 kJ/mol and 6.7838, respectively. The alloy has good thermoplasticity and no instability phenomenon occurs under experimental conditions, which indicates that the presence of nano-quasicrystals improves the deformation ability of the alloy. The optimal hot working region is 330–350 ℃ and 10^-3–10^-2 s^-1, that is, the high-temperature and low strain rate region.

• Oxidation Mechanism of Thermal Barrier Coatings with Air-Film Cooling Holes

  Gao Chao, Wang Senyuan, Liu Ling, Ma Zhuang, Yang Mingjia

  2025,54(1):191-201 DOI: 10.12442/j.issn.1002-185X.20240432

  Abstract(3) HTML(17) PDF(9.85 M)( 31)

  Abstract:Aiming to explore the oxidation mechanism of thermal barrier coatings with air-film cooling holes, in this research, femtosecond laser was used to prepare the thermal barrier coatings with air-film cooling holes. The microscopic morphology of the air-film cooling holes was observed, and the static oxidation of the perforated thermal barrier coatings was studied at 1000 and 1150 ℃. The growth rate constant of thermally grown oxide (TGO) of the perforated coating is 0.372 μm²·h^-1 after the static oxidation at 1000 ℃. The thickness of TGO is increased rapidly and then slowly with the prolongation of the oxidation time. After the static oxidation at 1150 ℃, the growth rate constant of TGO of the perforated coating is 1.26 μm²·h^-1, which is slightly larger than that of the unprocessed coating. After oxidation for 100 h, the thickness of TGO at the interface of the ceramic layer and the bonding layer is 11.610 μm, which is close to that of the unprocessed coating. The results show that the growth rate of TGO at the interface of the ceramic layer and the bonding layer is significantly increased and the oxidation process is accelerated with the increase in oxidation temperature. At the same oxidation temperature, the air-film cooling holes accelerate the growth rate of TGO during the short-time oxidation process, which has little effect on the thickness of TGO after oxidation for 100 h.

>Materials Science

• Effect of Cr₂O₃ Coating on Wettability and Interfacial Reaction Between Silicon-Based Ceramic Core and Nickel-Based Single Crystal Superalloy

  He Jiabao, Wang Liang, Zou Mingke, Zhang Chaowei, Wang Xinguang, Jiang Sumeng, Wu Jiaxin, Meng Jie, Zhou Yizhou

  2025,54(1):202-208 DOI: 10.12442/j.issn.1002-185X.20230706

  Abstract(8) HTML(24) PDF(4.39 M)( 41)

  Abstract:This research applied Cr₂O₃ coating on the surface of silicon-based ceramic core through multi-arc ion plating method. The effect of Cr₂O₃ coating on wetting behavior and interface reaction behavior of silicon-based ceramic core and nickel-based single crystal superalloy after contact at 1550 ℃ were studied using high-temperature in-situ droplet method. The interface morphology, element distribution, and reaction products after the interface reaction were analyzed using SEM, EDS, and XRD. The results show that the wetting angle between nickel-based single crystal superalloy and silicon-based ceramic core coated with Cr₂O₃ is 98.29°. Hf and Al in superalloy melt react with Cr₂O₃ coating, generating HfO₂, Al₂O₃, and free Cr at the bottom of superalloy. The generated Al₂O₃ forms a protective layer to prevent the diffusion of active elements in superalloy to the interface. However, a small amount of superalloy melt still reacts with the silicon-based ceramic substrate without coating protection, generating Al₂O₃ and free Si at the interface. The generated Cr and Si are enriched at the interface and form CrSi₂ on the superalloy surface. Part of Si diffuses from the surface of the superalloy to the interior, forming (Mo,W,Re)₅Si₃ with refractory elements such as W near the surface of superalloy. The results indicate that the wetting angle of nickel-based single crystal superalloy on silicon-based ceramic core coated with Cr₂O₃ is smaller than that on unmodified silicon-based ceramic cores, and its wettability is better. Based on the above analyses, the Cr₂O₃ coating on the surface of silicon-based cores is beneficial to improve the filling of alloy at local positions of castings, but its control effect on interface reactions is limited.

• Effect of α Phase on Stress Corrosion Behavior of Metastable β Titanium Alloy Ti-5.5Cr-5Al-4Mo-3Nb-2Zr in 3.5wt% NaCl Solution

  Liu Xuan, Zhang Haoyu, Wang Shengyuan, Zhou Ge, Cheng Jun, Chen Lijia

  2025,54(1):209-217 DOI: 10.12442/j.issn.1002-185X.20230681

  Abstract(3) HTML(17) PDF(7.30 M)( 32)

  Abstract:A metastable β titanium alloy Ti-5.5Cr-5Al-4Mo-3Nb-2Zr was designed. Three types of microstructure with different α phases were obtained by different heat treatment methods. The effects of α phase on stress corrosion behavior of the alloy were investigated by SEM, TEM, electrochemical test, and slow strain rate tensile test. The results show that after aging treatment at 650 ℃ for 6 h, the secondary α_s phase is coarsened (microstructure No.: M1). After solution treatment at 790 ℃ for 0.5 h at the two-phase zone, a coarse primary α_p phase (microstructure No.: M2) is formed. After solution treatment at 790 ℃ for 0.5 h and aging treatment at 650 ℃ for 6 h, coarse primary α_p phase and delicate secondary α_s phase (microstructure No.: M3) exist simultaneously. The electrochemical test results show that the self-corrosion current density of M3 is relatively low of 1.10×10^-8 A/cm². The polarization resistance of M3 is the highest at 2.30×10¹⁰ Ω·cm², which indicates the best corrosion resistance of M3, followed by M2, and M1 has the worst corrosion resistance. The results of slow strain rate tensile tests indicate that M3 has the lowest stress corrosion susceptibility index of 5.0%, and its stress corrosion cracking susceptibility is relatively low. The interaction of the hydrogen absorption-induced dislocation emission and the hydrogen-enhanced localized plasticity can explain the stress corrosion cracking mechanism.

• Uniaxial Tensile and Bulging Properties of Ti/Al Micro-laminated Composite Sheet

  Li Bobo, Fan Jiangkun, Xu Yali, Huang Zhenghao, Lin Peng, Gao Fuyang, Tao Huifa, Li Jinshan, Wang Fei, Wang Zhe

  2025,54(1):218-223 DOI: 10.12442/j.issn.1002-185X.20230683

  Abstract(3) HTML(15) PDF(3.43 M)( 35)

  Abstract:Ti/Al micro-laminated composite sheet with alternate arrangement of Ti/TiAl₃/Al laminate microstructure was fabricated through vacuum hot-pressing method. The uniaxial tensile deformation behavior at high temperature and the bulging formability were investigated by uniaxial tensile experiment and gas bulging experiment, respectively. The results show that the composite sheet hot pressed for 15 min exhibits better plastic deformation behavior because the hard and brittle TiAl₃ layer is thin. When the composite is deformed at elevated temperatures, the cracks of the composite sheet are blunted, which inhibits the propagation of cracks in TiAl₃ layer, so the elongation and limiting bulging rate at 600 ℃ reach 135% and 45%, respectively. At the top region of the bulged spherical shell, the Ti layer and Al layer both undergo severe deformation and are necked, the Ti/Al interface is wavy, the TiAl₃ layer breaks into islands, with Al layer filling their gaps, and no cracks are formed.

• First-Principles Calculations of Absorption Properties of Cs₂F₅Li₃ to Li₂S

  Wang Mengxiang, Xu Jiaxin, Qin Tianxin, Liu Xinyi, Xiao Chengjie, Liu Zhengtang, Liu Qijun, Jiang Chenglu

  2025,54(1):224-231 DOI: 10.12442/j.issn.1002-185X.20230716

  Abstract(3) HTML(27) PDF(3.52 M)( 30)

  Abstract:Lithium-sulfur batteries (LSBs) have extremely high theoretical energy density and low-cost cathode materials. However, the recycling of LSBs will produce polysulfides (LiPSs), which has a serious “shuttle effect”, resulting in highly polarized batteries, impaired battery performance, and even safety issues, and making the application of LSBs still extremely challenging. In this work, the binding energy of was used to discuss the absorption capacity of Cs₂F₅Li₃ to Li₂S, i.e., the ability to inhibit its “shuttle effect”. Based on the first-principles method of density functional theory, Cs₂F₅Li₃ and Li₂S were simulated by CASTEP software, and the binding energy of Cs₂F₅Li₃ to Li₂S is –2.53 eV. In order to explore the mechanism of adsorption, the basic properties, electronic structures, and charge transfer of Cs₂F₅Li₃ and Li₂S bulk phases, Li₂S(100), Cs₂F₅Li₃(001), and Cs₂F₅Li₃(001)-Li₂S(100) were used for analysis. The results show that the binding energy is provided by the ionic bond between F 2p and Li 1s2s as well as S 3p and Li 1s2s, the covalent bond between S 3p and F 2p, and the relaxation exchange energy of the bonds in the system. After the section, Cs₂F₅Li₃(001) has stronger chemical activity than Cs₂F₅Li₃, and Li₂S crystal changes from semiconductor property to metallic property. The metallic property of Cs₂F₅Li₃(001)-Li₂S(100) system improves, electrical conductivity is stronger, and photoelectric effect is stronger than that of Cs₂F₅Li₃(001). The adsorption energy calculation results show that Cs₂F₅Li₃ can inhibit the “shuttle effect” caused by the diffusion of Li₂S, which is conducive to alleviate the problems such as slow reaction kinetics, low activity, and reduced battery capacity caused by Li₂S, and it has a strong theoretical reference value for improving the performance of LSBs.

>Reviews

• Physical Antibacterial Surface Modifications on Titanium-Based Implant Materials

  Zhang Zhe, Liu Hui, Lin Manfeng, Cai Zongyuan, Zhao Dapeng

  2025,54(1):84-93 DOI: 10.12442/j.issn.1002-185X.20240527

  Abstract(11) HTML(48) PDF(2.07 M)( 42)

  Abstract:Infections associated with titanium (Ti)-based implants present significant challenges in clinical treatments, especially when biofilms already form on the implant surface. Many antimicrobial agents, including antibiotics, metallic nanoparticles and antimicrobial peptides, have been extensively used to deal with Ti implant infections. However, these chemical approaches suffer from potential toxicity, antibiotic resistance and poor long-term antibacterial performance. Hence, physical antibacterial surfaces on Ti-based implants have attracted increasing attention. The antibacterial behavior of different surfaces on Ti-based biomaterials against various bacteria only by physical properties of the implants themselves (e.g., nanotopography) or exogenous physical stimulus (e.g., photocatalysis) was reviewed, as well as parameters influencing the physical antibacterial processes, such as size, shape and density of the surface nanotextures, and bacterial growth phases. Besides, mechanisms of different fabrication techniques for the physical antibacterial surfaces on Ti-based biomaterials were also summarized.

• Research Status and Prospect of Irradiation Effects of Titanium Alloys for Nuclear Applications

  Hu Shuang, Wan Mingpan, Zhu Te, Cao Xingzhong

  2025,54(1):232-242 DOI: 10.12442/j.issn.1002-185X.20240529

  Abstract(27) HTML(69) PDF(4.91 M)( 70)

  Abstract:Titanium alloys, characterized by their high specific strength, low density, corrosion resistance, oxidation resistance, high-temperature stability, and low neutron cross-section, are increasingly utilized as critical components in marine and space nuclear power systems. To enhance the radiation resistance of titanium alloys and advance their widespread use in nuclear engineering, considerable efforts have been made to address key issues related to the irradiation effects of titanium alloys. This paper reviews the development and irradiation effect studies of titanium and its alloys in the nuclear domain and provides a comprehensive overview of defect evolution and interaction mechanism of different advanced titanium alloys under various particle irradiations (such as neutrons and ions). Additionally, it summarizes the impact of service conditions (temperature, stress, and irradiation) on the mechanical properties of titanium alloys, including hardness, tensile strength, fatigue, and creep. Finally, based on the research status on titanium alloys for nuclear applications, the paper explores future research directions of irradiation effect and trends to improve irradiation resistance.

• Research Progress on Welding of Metallic Glasses

  Gong Pan, Liu Xiaoqi, Huang Hu, Tang Xinlong, Zhuo Jun, Zhang Mao, Tang Xuefeng, Wang Xinyun, Liu Hui

  2025,54(1):243-253 DOI: 10.12442/j.issn.1002-185X.20240064

  Abstract(9) HTML(54) PDF(3.00 M)( 38)

  Abstract:Metallic glasses with excellent physical and chemical properties are hindered by their size constraints, limiting their practical applications. However, welding technique holds the potential to overcome these limitations. Welding methods of metallic glasses can be classified into liquid phase welding and solid phase welding, each involving distinct mechanisms to form amorphous joints. Effective preventing crystallization is crucial for obtaining high quality joints. This paper provides a systematic and comprehensive review of the research in the field of metallic glass welding, and summarizes the research status of metallic glass and metallic glass welding as well as metallic glass and crystalline metal welding. It focuses on the characteristics and limitations of different welding techniques to achieve fully amorphous welded parts. Additionally, it reviews the research status of metallic glasses as solder materials in brazing process and analyzes the potential applications of metallic glass-based brazing materials, and summarizes approaches for enhancing the mechanical properties of brazed joints. Finally, this paper outlines prospects for the future research and development of metallic glass welding.

• Research Progress on Cryogenic Tribology of Several Common Metal Materials

  Zhu Longhui, Jiao Zhichao, Shi Yeran, Zhou Qing, Ren Yue, Wang Haifeng

  2025,54(1):254-262 DOI: 10.12442/j.issn.1002-185X.20240484

  Abstract(15) HTML(47) PDF(4.14 M)( 39)

  Abstract:In recent years, the rapid development of aviation industry, low temperature superconductivity, hydrogen energy power and other fields has increased the demand for the reliability of equipment operation in low temperature environment. Low temperature will cause the failure of lubricants and the deterioration of mechanical properties of metals, resulting in increasingly terrible lubrication problems. Metal materials are confronted with the severe service environment of dry friction at low temperature. Therefore, the excellent friction and wear performance of the material is a key factor to ensure the long-term stable operation of the mechanical equipment at low temperature. This paper describes the challenges of low temperature lubrication, including low temperature lubrication failure and metal ductile-to-brittle transition. Then we introduce the common low temperature friction environment of metal materials. Finally, the steel, titanium alloy, aluminum alloy and multi-principal element alloy with excellent properties at low temperature are introduced, and the future development trend in this field is prospected.

• Research Advances on Solid Powder-Pack Infiltration on Surface of Titanium and Its Alloys

  Tang Zikun, Duan Yonghua, Zheng Shanju, Peng Mingjun, Li Mengnie, Li Jun

  2025,54(1):263-279 DOI: 10.12442/j.issn.1002-185X.20240517

  Abstract(4) HTML(35) PDF(4.84 M)( 37)

  Abstract:Titanium and its alloys exhibit inherent limitations in complex environments due to their low hardness, poor wear resistance, and weak high-temperature oxidation resistance. Solid powder-pack infiltration technique can effectively enhance the surface hardness, wear resistance, and high-temperature performance of titanium and its alloys. The morphology of the infiltration layer is significantly influenced by temperature, holding time, and infiltration agent. The incorporation of carbon and boron elements can substantially improve surface hardness and wear resistance, while aluminum infiltration enhances high-temperature oxidation resistance and strengthens the interfacial bonding between the infiltration layer and substrate. By optimizing process parameters, multi-component layers can be fabricated to achieve superior comprehensive properties. However, there are still some problems to be solved, including surface porosity in borided layers, weak adhesion between the infiltration layer and substrate, incomplete development of multi-element solid powder-pack infiltration techniques, long processing time, and high temperature.

• Research Status and Prospects of High-Strength Titanium Alloys Fabricated by Selective Laser Melting

  Ma Yinfan, Fan Jiangkun, Tang Luyao, Zhai Haoyu, Zhang Zhixin, Chen Biao, Wang Jun, Tang Bin, Kou Hongchao, Li Jinshan

  2025,54(1):280-292 DOI: 10.12442/j.issn.1002-185X.20230690

  Abstract(14) HTML(34) PDF(9.38 M)( 57)

  Abstract:High-strength titanium alloys, represented by near/metastable β titanium alloys, have high specific strength, good plastic processing properties, and excellent hardenability, and they can be strengthened through heat treatment to get a better match of strength-plasticity-toughness. They have been widely used in load-bearing components of major equipment in aerospace and other fields. Selective laser melting (SLM), as an important technique in the field of titanium alloy additive manufacturing, has significant advantages such as near-net shaping and integrated forming of complex structures. So it has become a key development technique and cutting-edge direction in the aerospace manufacturing field. This review focuses on the principle and characteristics of SLM, starting from the extremely high heating/cooling rate and unique thermal cycle history of SLMed high-strength titanium alloy, and primarily discusses the microstructural features, phase composition, and mechanical properties of high-strength titanium alloys. The types of heat treatment processes of SLMed high-strength titanium alloy and their main influencing rules are summarized, aiming to provide a reference for obtaining excellent mechanical property match. Finally, drawing upon an analysis of existing research outcomes, the challenges of SLMed high-strength titanium alloys are summarized. It also offers a forward-looking perspective on potential research directions in this field.

Online First

• Interfacial and Mechanical Property Comparison of Cu/Al Composite Plates Manufactured by Rolling and Underwater Explosive Welding

  Available online:February 18, 2025  DOI: 10.12442/j.issn.1002-185X.20240745

  Abstract(11) PDF(1.11 M)(7)

  Abstract:Cu/Al composites are widely utilized across various industries due to their lightweight and excellent electrical conductivity. However, the impact of different manufacturing methods on the interfacial structure and mechanical properties of these composites remains significant. In this study, Cu/Al composite plates were fabricated using rolling and underwater explosive welding techniques to systematically compare their interfacial microstructure and mechanical performance. Interface morphology, grain orientation, grain boundary characteristics, and phase distribution were analyzed through optical microscopy, scanning electron microscopy, and electron backscatter diffraction. Mechanical properties were assessed using tensile shear tests, 90° bending tests, and hardness measurements, with Vickers hardness and nanoindentation tests providing further insight into hardness distributions. The results indicate that the diffusion layer in rolled Cu/Al composites is relatively fragile, while those produced by underwater explosive welding feature a diffusion layer approximately 18 μm thick, metallurgically bonded through atomic diffusion. The tensile shear strength of these composites ranges from 64.14 to 70.84 MPa, with superior flexural performance demonstrated in the 90° three-point bending test by the underwater explosive welded samples. This study elucidates the effects of distinct manufacturing methods on the interfacial properties and mechanical performance of Cu/Al composites, offering essential insights for selection of manufacturing method and application.

• Effect of Decreasing Homogenization Temperature on Microstructure and Properties of 2024-T3 Alloy

  Wang Yali, Cao Lingfei, Wen Qinghong, Jiang Yuan, Wu Xiaodong

  Available online:February 17, 2025  DOI: 10.12442/j.issn.1002-185X.20240689

  Abstract(7) PDF(1.35 M)(2)

  Abstract:The effect of decreasing the homogenization temperature on the microstructure and mechanical properties of 2024-T3 alloy was investigated. The results show that the area fractions of the residual coarse secondary phases after homogenization at 430 ℃ or 460 ℃ for 24 h followed by rolling are close to each other, and both are higher than that of the alloy homogenized at 490 ℃ for 24 h as routinely used in the industry. The alloys with homogenization of 430 ℃/24 h or 460 ℃/24 h and solution treatment have higher recrystallization fractions and finer grain sizes due to the PSN (Particle Stimulated Nucleation) effect of the coarse secondary phase. Hardness tests and tensile tests show that the peak hardness, tensile strength, yield strength, and elongation of the three alloys are relatively close to each other. Therefore, appropriately decreasing the homogenization temperature can improve the uniformity of grain size, reduce the cost, and maintain the excellent tensile properties of 2024-T3 plates. Whereas the high-temperature homogenization of 490 ℃/24 h can make the 2024-T3 sheet have relatively good plasticity and toughness.

• The influence of N2 flow on the micro-structure and corrosion resistance of TaN coatings on bipolar plates for PEM electrolyser

  Jianping Gao, Yuangjiang Lv, Yongjing Li, Wenqian Sun, BiYing Ren, Zhengfei Dai, 马飞

  Available online:February 17, 2025  DOI: 10.12442/j.issn.1002-185X.20240720

  Abstract(8) PDF(1.28 M)(3)

  Abstract:Corrosion shortens the service period of bipolar plates (BPs) and increases the costs of proton exchange membrane water electrolyser (PEMWE). In this work, TaN coatings are deposited on Ti BPs by magnetron sputtering to improve the corrosion resistance and service period, and the influences of N2 flow on the surface morphology, hydrophobicity, crystallinity, corrosion resistance and interfacial contact resistance of TaN coatings are studied in details. As the N2 flow increases, the roughness of TaN coatings decreases firstly and then increases in accordance with the hydrophobicity. At the N2 flow of 3 sccm, TaN coating with the larger grain size presents the lower roughness and hydrophobicity. As a result, the coating possesses the lowest Icorr of 2.82 μA?cm-2 and the highest Ucorr of -0.184 V vs. RHE in the simulated PEMWE environment. After 10 h potentiostatic polarization test, fewer corrosion pits are observed on the TaN coatings deposited at the 3 sccm N2 flow. Hence, the TaN coating on BPs could improve the corrosion resistance properties and thus enhance the electrolysis efficiency (68.87%) in the tested single electrolytic cell after 75 h.

• Quantitative Analysis of Low Cycle Fatigue Fracture Stress in Nickel-Based Single Crystal Superalloys based on crack tip plastic zone

  Liu Xinling, Deng Zhiwei, Tian Fuzheng, Wang Xueyun, Li zhen

  Available online:February 17, 2025  DOI: 10.12442/j.issn.1002-185X.20240731

  Abstract(6) PDF(1.11 M)(1)

  Abstract:Low cycle fatigue failure is the main failure mode of tenon part of single crystal turbine blades. Due to the difference between the actual working load and the design load, the stress leading to fatigue failure often needs to be given after fatigue failure, and the fracture is a comprehensive reflection of load and temperature. Quantitative analysis of the fracture and inverse fatigue stress have important engineering application value in blade failure analysis. The unique microstructure and crystal structure of single superalloy make its fatigue fracture characteristics different from those of polycrystalline materials. The main fatigue fracture characteristics of single crystal superalloy are slip plane rather than fatigue band. A model and method for quantitative analysis of crack tip plastic zone are presented in this paper. There is a certain Angle between fatigue fracture and load of single superalloy, which is a composite cracking mode rather than a type Ⅰcracking mode. According to the cracking characteristics of single superalloy,, in this paper, using the test data of DD6 single-crystal high-temperature alloy under the condition of 530 ℃ and strain ratio r=0.05, the hysteresis return line of its different life intervals is analyzed, and the results show that: the life span is between one thousand and ten thousand times, and its hysteresis loop is very narrow; the life span is greater than ten thousand times, and its hysteresis loop is basically a straight line; it shows that DD6 single-crystal high-temperature alloy under the conditions of 530 ℃ and strain ratio r=0.05 has the small yielding characteristics. Based on this, for the low-week fatigue fracture, the characteristics of crack initiation and extension stage and its fracture characteristics were studied, and a quantitative analysis model of fatigue stress fracture was established by considering the composite cracking and based on rp in the plastic zone at the crack tip, use a total of 12 crack locations a for 3 specimens, the quantitative analysis of fatigue stress fractures at different a locations is carried out, and the analysis results show that the error of fatigue initiation stress was within 1.3 times, and that of inverse extrapolation result of the first stage of extension was within 1.5 times of the dispersion band. The results provide models and methods for quantitative fracture analysis of stresses in single-crystal high-temperature alloys mainly by slip-surface cracking (non-fatigue strips).

• Effect of Ar+ irradiation on microstructure and corrosion resistance of Zr-Sn-Nb alloy

  Hu Lijuan, Qiang Yuanyuan, Zhou Mingyang, Xin Yong, Gu Zhiyuan, Shi Jin, Xie Yaoping, Xu Shitong, Yao Meiyi, Zhou Bangxin

  Available online:February 17, 2025  DOI: 10.12442/j.issn.1002-185X.20240737

  Abstract(2) PDF(3.19 M)(1)

  Abstract:Irradiation can induce the formation of a large number of defects in the matrix and oxide film of zirconium alloys, thereby facilitating the migration and diffusion of O2- and corrosive media and accelerating the corrosion of zirconium alloys. To investigate the influence of irradiation on Zr-Sn-Nb alloys, Ar+ was implanted into the alloys at an irradiation fluence of 5.1×1015 ions/cm2. The original and irradiated samples were subjected to corrosion tests in an aqueous solution of 360 ℃/18.6 MPa/3.5 ppm Li + 1000 ppm B (alkaline water) and in steam at 400 ℃/10.3 MPa (neutral water), respectively. The microstructure was analyzed using XRD, SEM, and TEM characterization methods to study the effect of Ar+ irradiation on the corrosion resistance of Zr-Sn-Nb alloys in different corrosion environments. The results indicate that irradiation can lead to the amorphization of the second phase particles, among which the hcp-Zr (Fe,Nb)2 second phase is more likely to form an amorphous state than the bcc-β-Nb second phase. Furthermore, the second phase undergoes amorphization at the same time as element diffusion, and during the oxidation process of the second phase it experiences lattice mismatch with the oxide film, resulting in cracks extending from the top of the second phase to its sides. Within 300 days, the damage dose of Ar ion irradiation at 5 dpa has little effect on the corrosion resistance of Zr-Sn-Nb alloys in the aqueous solution of 3.5 ppm Li + 1000 ppm B. In contrast, in steam at 400 ℃/10.3 MPa, the stress relaxation during the irradiation process results in a reduction in defects, which subsequently slows down the oxygen diffusion within the oxide film and decelerates the corrosion process. Therefore, irradiation has a certain improving effect on the corrosion resistance of zirconium alloys.

• Effects of the addition of CNTs on microstructure, mechanics and thermal conductivity of pure copper in laser powder bed melting

  Laixia Yang, Longbo Zhang, Qidong Xie, Yanze Zhang, Mengjia Yang, Feng Mao, Zhen Chen

  Available online:February 17, 2025  DOI: 10.12442/j.issn.1002-185X.20240754

  Abstract(6) PDF(1019.58 K)(4)

  Abstract:The laser powder bed fusion (L-PBF) process for manufacturing copper typically exhibits poor strength-ductility coordination； the addition of enhancers is usually an effective way to improve it. However, there is relatively limited research on Cu composites. To explore the impact of enhancements on Cu, we used a Cu-CNTs mixed powder as the base and applied the L-PBF technology to produce a Cu-CNTs composite. We studied its forming performance, microstructure, and mechanical properties, as well as its conductive and thermal properties. The resulting composite has a high relative density of consolidated Cu-CNTs material. The addition of CNTs results in non-uniform microstructure with equiaxed grains at the edges of the melt pool and columnar grains at the center. Compared to pure copper, the overall mechanical properties of the composite are improved (tensile strength increased by 52.8%, elongation increased by 115.9%), and the electrical and thermal properties are also enhanced (thermal conductivity increased by 10.8%, electrical conductivity increased by 12.7%). The results indicate that the addition of CNTs can increase the tensile strength and elongation, as well as the electrical and thermal properties of copper. Therefore, this material provides an efficient pathway for designing more efficient heat sink structures.

• Effect of pore structure on forming quality and performance of Mg-5Zn magnesium alloy porous bone repair scaffold fabricated by SLM

  Zhao Lun, Sun Zhichao, Wang Chang, Zhang Pengsheng, Tang Shuai, Zhang Baoxin

  Available online:December 02, 2024  DOI: 10.12442/j.issn.1002-185X.20240618

  Abstract(87) PDF(1.94 M)(75)

  Abstract:Four types of Mg-5Zn porous scaffolds with different pore geometries, including body-centered cubic (BCC), rhombic dodecahedron (RD), primitive (P), and gyroid (G), were designed and fabricated using SLM. Their forming quality, compression mechanical properties, and degradation behavior were investigated. The results indicate the scaffolds fabricated exhibited good dimensional accuracy, and the surface chemical polishing significantly improved the surface quality while reducing forming errors. Compared to the rod structures (BCC, RD), the surface structures (G, P) scaffolds had less powder particle adhesion. For the same design porosity, the G porous scaffold exhibited the best forming quality. The predominant failure mode of scaffolds during compression was a 45° shear fracture. At a porosity of 75%, the compression performance of all scaffolds met the compressive performance requirements of cancellous bone, and BCC and G structures showed relatively better compression performance. Immersed in Hank"s solution for 168 hours, the B-2-75% pore structure scaffold exhibited severe localized corrosion, with fractures in partial pillar connections. In contrast, the G-3-75% pore structure scaffold mainly underwent uniform corrosion, maintaining structural integrity, and the corrosion rate and loss of compressive properties are less than those of the B-2-75% structure. After comparison, the G-pore structure scaffold is preferred.

• The Influence of Current Density and Copper Ion Concentration on the Properties of Electrodeposited Cu-Ni Coatings

  Xuyan Guo, Zhuangzhuang Xiong, Guixiang Wang, Qiang Zhou, Yanxiong Wu, Delong Kong, Fuqiu Ma, Ruizhi Wu

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240460

  Abstract(56) PDF(1000.11 K)(123)

  Abstract:This article investigates a straightforward, highly effective, and eco-friendly technique for preserving carbon steel surfaces against corrosion, by depositing Cu-Ni alloy coatings on the workpiece"s surface to impede corrosive medium. The effects of current density and Cu2+ concentration on the composition, morphology, and composition of the coating were investigated using scanning electron microscopy, X-ray energy dispersive spectroscopy, Vickers hardness tester, friction and wear tester, and electrochemical testing. A cauliflower like Ni rich protrusion structure appears on the coating surface. The lower current density and Cu2+ concentration affect the Vickers hardness and wear resistance of the coating by affecting the grain microstructure and Cu/Ni content, both leading a decrease in hardness and wear resistance. When the current density is 10 mA/cm2 and the Cu2+ concentration is 0.1 mol/L, the corrosion current density of the deposited sample reached 1.389×10?5 A·cm?2, and its surface corrosion damage was significantly less than that of the sample without coating after 24 h of salt spray test. Research on the deposition mechanism indicates that Cu2+ undergoes instantaneous nucleation under diffusion control, tending towards vertical growth and forming cauliflower-like protrusions, while Ni2+ is controlled by electrochemistry to discharge uniformly across the surface.

• Numerical simulation of the springback on magnesium alloy

  Malidong

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240464

  Abstract(39) PDF(602.94 K)(127)

  Abstract:The bending springback of magnesium alloys is difficult to predict accurately in numerical simulations because of its anisotropic characteristics. The springback of magnesium alloys in v-shaped roll bending was analyzed more accurately using the error optimization function in Matlab to optimize the anisotropic potential values required for the Hill’48 yield criterion in ABAQUS. The optimized Hill’48 yield criterion model was used to numerically simulate the springback of magnesium alloy v-shaped roll bending. The simulation results were compared with the experimental results. The error between the springback change ratio obtained using the optimized Hill’48 yield criterion and experimentally formed parts was within 2%. Overall, the optimized Hill’48 yield criterion model can improve the springback prediction accuracy of magnesium alloy v-shaped roll forming.

• Research on Welding Characteristics of Titanium Alloy Joints by Hollow cathode vacuum arc Welding

  Xu Jianping, Gong Chunzhi

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240470

  Abstract(31) PDF(1.20 M)(96)

  Abstract:The microstructure of Ti-6Al-4V joints by hollow cathode vacuum arc welding with different gas flow rate was studied, and the tensile properties were investigated. The results show that the microstructure of base metal was mixture of α phase β phase. The microstructure of heat affected zone are equiaxed and primary α and needle martensite α′ dispersed in the transformed β. Two kinds of tissues distribution depends on the heat-affected area affected by the welding thermal cycle.The microstructure of welding seam consists mainly of α′ martensite phase. Reduce welding gas flow rate and increase welding energy density, resulting in coarsening and more scattered distribution of martensitic grains. The tensile strength of welded joint is higher than that of base metal.

• Construction of bimodal-grained Mg-Bi alloy composed of ultrafine grains and fine grains and its strengthening and toughening mechanisms

  mengshuaiju, songjinlong, chenkeyi, cuimin, wanglidong, biguangli, caochi, yangguirong

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240480

  Abstract(48) PDF(921.12 K)(113)

  Abstract:Low-temperature equal channel angular pressing (ECAP) processing technology has great potential in fabricating bimodal-grained alloys composed of ultrafine grains and fine grains. Besides, fine grain Mg-Bi based alloys demonstrate excellent low temperature plastic deformation performance. Based on this, a new inverse temperature field ECAP (ITF-ECAP) processing method was developed to realize the severe plastic processing of a fine grained Mg-6Bi (B6) alloy at low temperature (<100 ℃) to construct a bimodal-grained microstructure composed of ultrafine (<1 μm) and fine grains (1-10 μm). The microstructure and mechanical properties characterization results show that dynamic recrystallization preferentially occurred at the initial grain boundaries of the fine-grained B6 alloy during the multi pass ITF-ECAP processing. Besides a large amount of submicron sized Mg3Bi2 phase precipitated during ITF-ECAP processing. As a result, bimodal-grained microstructure consisting of ultrafine grains with an average grain size (AGS) of about 600 nm and fine grain region with an AGS of about 2 μm was successfully constructed in B6 alloy through 4-pass ITF-ECAP processing. The volume fraction of the ultrafine grain region accounts for about 72.5 %. Due to the combined effects of grain-boundary strengthening, precipitation strengthening, dislocation strengthening, and back stress strengthening, the bimodal-grained B6 alloy exhibits excellent strength and ductility, with yield strength and elongation reaching 315.6±3.6 MPa and 22.3±1.0 %, respectively.

• Research Progress in Preparation of Titanium Matrix Composite Coatings by Cold Spraying: A Review

  Xu Yaxin, Zou Han, Huang Chunjie, Li Wenya

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240483

  Abstract(62) PDF(1.45 M)(131)

  Abstract:Cold spraying has great advantages in preparation of oxidization-sensitive metallic coatings because of the lower heat input and almost no oxidation resulting from its low temperature process. Combined with the convenience of cold spraying in manufacturing particle reinforced composite coatings, titanium matrix composite coatings prepared by cold spraying can compensate for the shortcomings of poor wear resistance of pure titanium or titanium alloys. In addition, one can also get the functional coatings besides the structural coatings. According to the existing research reports, the deposition behaviors and mechanisms of cold-sprayed titanium matrix composite coatings were summarized. By analyzing the porosity and deposition efficiency, the effect of strengthening on the microstructure of the cold-sprayed titanium matrix composite coatings was explained. The mechanism of reinforcement on mechanical and wear performance of titanium matrix composite coatings were revealed. Finally, the future application of cold-sprayed titanium matrix composite coatings is prospected, and several promising directions are listed.

• Analysis of the SLM forming structure and cracking mechanism of ZGH451 nickel-based high-temperature alloy

  wuyin, Zhang Hao, Zhu Yuping, Fang Shimin, Ding Yaoyao, Liang Liwen, Yan Guangqiang, Qiu Zixiang, Wang Haixuan, Dongye Shengshua, Tian Miaocheng, Yang Yang, Huang Qizhong, Zheng Yongjian

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240487

  Abstract(58) PDF(1.65 M)(123)

  Abstract:This study focuses on the SLM (Selective Laser Melting) formed ZGH451 nickel-based superalloy, revealing the mechanism by which solidification liquid films lead to crack initiation and clarifying the roles of alloy elements and texture in forming crack defects. Experimental results indicate that cracks in the SLM process of ZGH451 nickel-based superalloy can be mainly categorized into internal solidification cracks and edge cold cracks. During the late solidification stage, low-melting-point phase liquid films exist between dendrites, and high-melting-point Cr element particles at the solidification front hinder melt feeding. The insufficient feeding and thermal stress between dendrites cause the liquid film"s rupture, leading to solidification cracks in the core of the material. In the alloy"s contour region, high cooling rates and significant thermal stress lead to residual stress accumulation, which exceeds the material"s strength limit or grain boundary cohesion strength, resulting in the formation of cold cracks. When the input laser energy density is below 53.6 J/mm3, pores and lack of fusion defects increase significantly in the alloy, while exceeding 130.9 J/mm3 sharply increases the probability of keyhole formation along the melt pool track. These defects can induce cracks under stress. The more TiC and other carbide particles precipitate between dendrites, the greater grain misorientation, and the higher the alloy"s crack sensitivity. The deposited state of ZGH451 nickel-based superalloy is mainly composed of γ and γ" phases, with a preferred orientation on the (100) plane. The average aspect ratio of the grains reaches 11.25, and the significant texture exacerbates stress concentration at the grain edges and tips, promoting crack initiation and altering crack propagation direction.

• The Effect of Different Heat Treatments on Surface Microstructures and Anodic Oxide Film Structures of an Al-5.6Mg Alloy Sheets

  jiangzhongyu

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240492

  Abstract(21) PDF(833.41 K)(118)

  Abstract:The effect of different intermediate annealing heat treatments on the surface microstructures and anodic oxide film structures of rolled sheets of an Al-5.6Mg alloy was studied. The results show that when the continuous annealing is used instead of the static state annealing in intermediate annealing process to control microstructures of the sheets, the surface grain size of the sheets can be reduced by about 60 %, and size of the Mg precipitated phase (Mg2Al3) can be reduced by about 67 %. Under the combined influence of grain size, uniform precipitation phase, and texture, the highest glossiness can be obtained, which was attributed to continuous intermediate annealing and stabilization annealing at low temperature. The uniform grain and precipitation structures is beneficial to reduce the inhomogeneous dissolution of the oxide film and to obtain the anodic oxide film with uniform thickness and high gloss.

• The Influence of Ni Interlayer Thickness on the Microstructure and Mechanical Properties of Zr-4/Nb/Ni/316SS Diffusion Bonded Joint

  Li Qianru, Zhang Fan, Niu Shiyu, Wang ying, Yang Zhenwen

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240495

  Abstract(50) PDF(1.24 M)(146)

  Abstract:This study systematically investigates the influence of Ni interlayer thickness on the microstructure, mechanical properties, and corrosion resistance of Zr-4/Nb/Ni/316SS diffusion bonded joints. The experimental results reveal that the typical interface microstructure of the joints consists of Zr-4/β-(Zr, Nb)/Nb/Ni3Nb/Ni/316SS. The shear strength of the joints initially increases and subsequently decreases with increasing Ni interlayer thickness, reaching a peak value of 380 MPa at an interlayer thickness of 30 μm. To elucidate the effect of Ni interlayer thickness on the mechanical properties, the microstructural characteristics of the joint interfaces were characterized, and Abaqus simulations were conducted to analyze the residual stress distribution across the interfaces. The comparative analysis of the mechanical properties and fracture behavior, combined with simulation results, indicates that while thicker Ni interlayers are more effective in alleviating residual stress, excessively thick interlayers lead to a reduction in shear strength due to their enhanced ductility. Additionally, the corrosion resistance of the joints was assessed using full immersion corrosion tests. The results indicate that the corrosion rate decreases with a reduction in Ni interlayer thickness, with the optimum corrosion resistance observed at an interlayer thickness of 10 μm. In conclusion, it is recommended that the Ni interlayer thickness be maintained between 10 μm and 30 μm to achieve a balance between mechanical properties and corrosion resistance.

• Study on thermal stability of W-Re alloy and influence of high temperature oxidation behavior temperature

  Nan Lingxin, Qi Yanfei, Xu Pengfei, Li Yungang, Pang Binghe

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240509

  Abstract(78) PDF(1.33 M)(114)

  Abstract:Superalloy has a very important position in the development of nuclear fusion and other fields, and the use of the requirement is to form a stable and protective oxide under high temperature service conditions, and the oxide can prevent further oxidation of the alloy. In order to study the stability and oxidation resistance of W-3%Re alloy at high temperature, the thermal stability experiments of W and W-3%Re alloy were carried out at (500,700,900 ℃) for 6h. Oxidation experiments were carried out at different temperatures (700,800,900 ℃) for 18h. The phase composition, oxidation kinetics, oxidation products and surface morphology of the oxide film were analyzed by XRD, SEM, LSM800 automatic 3D morphology analyzer and Hysitron TI Premier Nanoindentation apparatus. The results show that the quality of the alloy increases with the extension of oxidation time. During the oxidation process, the grain size of W-3%Re alloy is reduced, the oxidation film can be formed faster, the surface oxide layer is gradually thicker, and the high temperature oxidation resistance of W-3%Re alloy is improved. Compared with W, the chemical stability of the Re oxide in W-3%Re alloy is higher, and it shows a lower oxidation rate constant when it is oxidized at 700℃ for 18h. At this time, the W-3%Re alloy is a weak oxidation grade, and the density of the oxide layer is improved to a certain extent during the oxidation process. The results show that the addition of Re can improve the high temperature oxidation resistance of W material.

• Preparation of 7N high-purity indium by vacuum distillation-zone refining combination

  Tian Qinghua, Hu Zhixiang, He Zhiqiang, Guo Xueyi, Zhu Liu, Xu Zhipeng

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240439

  Abstract(31) PDF(803.18 K)(81)

  Abstract:High-purity indium finds extensive application in the aerospace, electronics, medical, energy, and national defense sectors. Its purity and impurity content significantly influence these applications. In this study, ultrahigh-purity indium was prepared by combining zone refining with vacuum distillation. The average removal efficiency of impurity Sb can approach 95%, while the removal efficiency of impurities Sn and Bi could reach over 95% and the removal efficiency of Si, Fe, Ni, and Pb could reach over 85%. Ultimately, the amount of Sn and Sb impurities was reduced to 2.0 ppb and 4.1 ppb, respectively, and the majority of impurities, including Fe, Ni, Pb, and Bi, were reduced to levels below the instrumental detection limit. The overall impurity removal efficiency was 90.9%, and the indium purity was 7N9.

• Influence of silicide precipitation on mechanical properties in Ti-Al-Zr-Sn-Mo -W-Si system titanium alloy

  Zhang Xiaoyuan, Li Fuguo, Du Yuxuan, Liu Xianghong, Wang Kaixuan, Li Jieyao, Song Minglong

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240444

  Abstract(27) PDF(1.26 M)(100)

  Abstract:Comparative analysis of the differences in tensile strength and impact toughness between the TC25 alloy and TC25G alloy of Ti-Al-Zr-Sn-Mo-W-Si system titanium alloys was carried out, and the root causes of the differences in impact toughness between the two alloys and the alloy strengthening mechanism were elucidated through the observation of the SEM fracture morphology and the analysis of the TEM microscopic deformation mechanism. The results show that the precipitated phase in the impact fracture of TC25G alloy is ZrSi or TiZrSi compounds, which plays the role of second-phase reinforcement and is conducive to the enhancement of the alloy strength, and the precipitates are conducive to the extension of impact cracks, thus reducing the impact toughness of the alloy. TC25 alloy impact fracture microstructure cracks generally extend along the primary α phase phase boundary, while TC25G alloy impact fracture microstructure cracks through the primary α phase; so that the TC25 alloy crack extension path longer, and thus the alloy has a higher impact toughness. TEM observations show that the number of dislocation slip traces and dislocation plugging in TC25G alloy is significantly higher than that in TC25 alloy. The presence of a large number of plugged dislocations in the vicinity of the precipitates in TC25G alloy results in significant strengthening, leading to a higher strength of the alloy.

• Effects of temperature and twin boundaries on the mechanical properties and Protevin-Le chatelier(PLC) effect

  Gao Yubi, Wang Wenjuan, Yang Hui, Wang Xingmao, Xu Jiayu, Zhen Bing, Ding Yutian

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240445

  Abstract(16) PDF(2.83 M)(143)

  Abstract:In this paper, EBSD, SEM, TEM and quasi-static uniaxial tensile tests were used to study the effects of temperature and twin boundaries on the mechanical properties and Protevin-Le chatelier（PLC) effect of GH3625 alloy. The results show that with the increase of annealing temperature (1000 °C~1160 °C), the recrystallized grains of the annealed specimen grow, resulting in the annihilation of part of the annealed twin boundaries, which reduces the content and strength of the annealed twin boundaries of the alloy. And it is found that the lower the annealing temperature, the greater the critical strain value of the alloy with PLC. At the same time, the tensile deformation of the annealed specimen at 25 °C and 290 °C is mainly dominated by dislocation slip and deformation twin, while at 565 °C, the dislocation slip is mainly dominated by dislocation slip, and a large number of lamination faults are formed. With the increase of deformation temperature, dislocations tend to pass through grain boundaries and annealed twin boundaries, resulting in PLC, weakened grain boundary strengthening effect, and decreased alloy strength. In addition, the specimen with an annealing temperature of 1000 °C has an excellent combination of strength and plasticity in the temperature range of 25 °C~565 °C, which is mainly attributed to the interaction of pre-existing fine grains and a large number of annealed twin boundaries with dislocations, as well as the combined effect of deformed twins and lamination faults formed during tensile deformation. In addition, it is found that the twin content and deformation temperature have a significant effect on the rheological amplitude of the PLC.

• Preparation of high performance AZ31 magnesium alloy with bimodal grain structure by single pass hot rolling

  Ge Mao, Jiang Haitao, Zhang Yun

  Available online:November 21, 2024  DOI: 10.12442/j.issn.1002-185X.20240449

  Abstract(17) PDF(1.05 M)(119)

  Abstract:This paper focuses on the AZ31 magnesium alloy, utilizing single-pass hot rolling to fabricate an alloy with the bimodal grain structure, and examines how this structure enhances the alloy’s strength and plasticity. The experimental results show that the formation of the bimodal grain structure is more pronounced at rolling temperatures ranging from 350 ℃ to 450 ℃, especially under conditions of large reduction (≥40%). The optimized proportion and distribution of the bimodal grain structure play a pivotal role in simultaneously enhancing the alloy’s strength and ductility, significantly impacting the mechanical properties. The rolled sheet with the bimodal grain structure achieved an ultimate tensile strength of 258.3MPa and an elongation of 17.1% under a rolling reduction of 40%, with a rolling rate of 75 m/min and a rolling temperature of 400 ℃. Adjusting rolling parameters, including temperature, reduction ratio, and rolling rate, is crucial for optimizing the bimodal grain structure, thereby achieving a balance between improved plasticity and maintained high strength.

More++