2026,Volume 55, Issue 8

>Special Issue：titanium alloy

• Microstructure and Mechanical and Tribological Properties of WC-Co-Ce Cemented Carbide: First-Principles Calculations and Experiments

  Li Zewen, Chen Hao, Chen Liyong, Zhang Jianbo, Zhang Fan, Xie Xiaolong

  2026,55(8):1876-1888 DOI: 10.12442/j.issn.1002-185X.20250550

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  Abstract:The WC/Co and WC/CoCe interface models were constructed, and the interfacial energy, elastic constants, and charge distribution characteristics were calculated using first-principles calculations. WC-10Co, WC-10Co-0.5Ce, and WC-10Co-1Ce cemented carbides were fabricated via liquid-phase sintering. Microstructural analysis, mechanical testing, and friction and wear testing were conducted to investigate the influence of the rare earth element Ce on the overall performance of the cemented carbide. The calculated results indicate that doping with Ce promotes the formation of strong covalent bonds between W and Ce atoms at the interface, which increases the interfacial bonding energy, reduces the interfacial energy, and improves structural stability. Based on the elastic constants and electronic properties, it is predicted that the hardness, toughness, and wear resistance of the cemented carbide are enhanced. Experimental findings demonstrate that the optimal performance is achieved when the Ce content is 0.5wt%. At this concentration, the Vickers hardness reaches 1484 HV₃₀, the fracture toughness is 10.55 MPa?m^1/2, and the wear rate is 1.067×10^–5 mm³?N^–1?m^–1.

• Microstructural Evolution and Heterogeneous Precipitation of Laser Welded TB9 Alloy Joints

  Feng Jingru, Zhang Kezhao, Liu Dong, Yan Chunyan, Cheng Jiangbo, Bao Yefeng

  2026,55(8):1897-1906 DOI: 10.12442/j.issn.1002-185X.20250479

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  Abstract:The microstructural evolution during the laser welding and subsequent post-weld heat treatment processes of laser welded TB9 joints was investigated. Results show that, during the laser welding process, the average size of β grains in the fusion zone increases with the increase in laser power. During the aging treatment, the size of the α phase increases with the increase in temperature. Concurrently, the quantity of the α phase decreases. The size of the α phase also increases with the prolongation of holding time. Meanwhile, the morphology of α phase transforms from a needle-like structure to an elliptical one. After the heat treatments, the precipitation-free zones (PFZs) are observed in the fusion zone, heat-affected zone (HAZ), and base metal of the welded joint. The formation of PFZs is due to the inhomogeneous precipitation and growth of α phase. PFZs exist between the dendrite arms in the fusion zone, near the grain boundaries in HAZ, and near the low angle grain boundaries (LAGBs) and grain boundaries of the base metal. In the fusion zone, the formation of PFZs is due to the enrichment of element Cr between dendrite arms. In HAZ and base metal, the formation of PFZs is attributed to vacancy depletion around grain boundaries as well as LAGBs.

• Gamma Irradiation Influence on Ta Element Segregation and Mechanical Properties of Ti35 Alloy

  Li Huan, Yang Bohai, Xu Jianping, Wu Jinping

  2026,55(8):1929-1934 DOI: 10.12442/j.issn.1002-185X.20250466

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  Abstract:Based on the highly radioactive service environment of spent fuel reprocessing, the influence of gamma irradiation on the structure of Ti35 alloy was studied by applying gamma rays at different irradiation doses, and the structure-activity relationship between irradiation-induced structure and performance was established. The results show that gamma irradiation induces a large number of defects in Ti35 alloy, and the defect density increases with the increase in irradiation dose. The rapid migration of Ti atoms in the Ti35 alloy matrix caused by irradiation results in the formation of a body-centered cubic Ta-rich second phase in the granules, and the Ta content and size of this phase further increase with the increase in irradiation dose. Gamma irradiation significantly reduces the elongation of Ti35 alloy, which is related to the deformation and interface failure mechanism dominated by Ta-rich soft phase according interface analysis. The Ti35 alloy shows ductile fracture mode before and after irradiation, and it is found that gamma irradiation significantly increases the size and density of fracture micropores by observing the fracture morphology.

• Effect of Microstructure on Tensile Properties and High-Cycle Fatigue Behavior of a Low-Cost Ti-6Al-4V Alloy

  He Songzhi, Wei Guohuan, Yuan Wenzhi, Huang Meilin, Li Yushan, Zhao Qinyang, Zhang Yong, Zhang Qifei, Liang Gaofei, Chu Shuangjie

  2026,55(8):1935-1942 DOI: 10.12442/j.issn.1002-185X.20260117

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  Abstract:A low-cost Ti-6Al-4V (TC4) alloy fabricated by remelting TC4 scrap using electron beam cold hearth melting (EBCHM) combined with a short-process hot-rolling route was investigated. Two heat treatment conditions, namely stress-relief annealing and solution treatment followed by aging were adopted to study the influence of microstructure on the tensile properties and high-cycle fatigue (HCF) performance of the alloy. The results indicate that the stress-relieved alloy exhibits a typical basketweave α+β lamellar microstructure. After solution treatment and aging, the microstructure transforms into a heterogeneous structure consisting of coarsened α lamellae, equiaxed α grains, and transformed β. Compared with the annealed condition, the solution-aged alloy shows a significant improvement in ductility while maintaining relatively high strength, leading to a favorable strength-ductility synergy. This enhancement is primarily attributed to the cooperative deformation of coarsened α lamellae and equiaxed α grains, which effectively accommodate dislocation slip and promote the activation of higher-order slip systems, thereby improving the plastic deformation capability of the alloy. High-cycle fatigue tests reveal that the annealed alloy exhibits a higher fatigue strength. This behavior is associated with the basketweave lamellar microstructure, which facilitates crack deflection and prolongs the fatigue crack propagation path, thereby improving resistance to fatigue crack growth.

• Strain-Controlled Dwell Fatigue Behavior and Fracture Characteristics of Low-Cost Ti-2Fe-0.1B Alloy

  Wang Delong, Wang Chu, Liu Anjian, Dong Yuecheng, Igor V. Alexandrov

  2026,55(8):1987-1998 DOI: 10.12442/j.issn.1002-185X.20250187

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  Abstract:The low-cycle dwell fatigue behavior and fracture characteristics of a cost-effective Ti-2Fe-0.1B alloy with lamellar microstructure were investigated. Strain-controlled low-cycle fatigue tests incorporating tension-compression with dwell time of 0, 2, and 10 s were conducted under various strain amplitudes. The results reveal that at lower strain amplitudes (Δε_t/2=0.6%), specimens with all dwell durations exhibit continuous cyclic softening during initial cycles. Conversely, at higher strain amplitudes (Δε_t/2=1.4%), an initial cyclic hardening phase precedes subsequent softening, which is primarily attributed to dislocation multiplication and entanglement, forming temporary barriers that impede plastic deformation in early stages. The fatigue life of Ti-2Fe-0.1B alloy demonstrates significant strain amplitude and dwell time dependence. At high strain amplitude (Δε_t/2=1.4%), the life reduces (710→426 times). At intermediate strain amplitude (Δε_t/2=1.0%), specimens maintain stable fatigue life under short dwell periods (1604→1610 times), while low strain amplitude (Δε_t/2=0.6%) testing reveals non-monotonic life variations (15 478→8543→8887 times) with the prolongation of dwell time. Comparative analysis with conventional titanium alloys (TA15, Ti80) demonstrates that dwell fatigue resistance of Ti-2Fe-0.1B alloy is better. Microstructural characterization of fracture profiles reveals the presence of precipitated TiB phases. These high-strength and high-hardness precipitates contribute to enhanced matrix strength and can provide effective crack propagation resistance through reinforcement mechanisms, which improves the overall fatigue performance of alloy's.

• Effect of Homogenization Heat Treatment on Channel Segregation in Nb47Ti Alloy Ingot

  Shang Jinjin, Zhu Shigang, Li Binqiang, Bai Huiwen, Yang Ce, Lei Qiang, He Tao, Liu Xianghong, Zeng Weidong

  2026,55(8):2028-2035 DOI: 10.12442/j.issn.1002-185X.20250202

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  Abstract:Channel segregation in Nb47Ti alloy is prone to occur during vacuum arc remelting (VAR), which significantly degrades its processability. Molecular dynamics simulations reveal that for the Ti-Nb system under isothermal holding at 1170 ℃, the mean squared displacement (MSD) of Ti and Nb increases with the increase in Nb content, indicating that homogenization treatment effectively alleviates microsegregation. In Nb47Ti alloy, solute atoms Nb exhibit significantly stronger displacement amplitudes and diffusion trajectories than the Ti matrix. The effects of homogenization heat treatment at 1170 ℃ for 5.5 and 10 h on the microsegregation and channel segregation of Nb47Ti ingot with diameter of 520 mm were analyzed. The results show that the segregation index of microsegregation decreases by 0.27% and 0.53% after homogenization, but no significant improvement is observed in the morphology, quantity, or size of channel segregation. Increasing the heat treatment temperature or prolonging the duration has an extremely minimal effect on reducing channel segregation, and may lead to excessive hydrogen content issues.

• Effect of Heat Treatment on Mechanical Properties of TC4-0.55Fe Titanium Alloy Tube

  He Miaoxia, Jiang Qing, Guo Yumeng, Dong Yuecheng, Igor V. Alexandrov

  2026,55(8):2036-2049 DOI: 10.12442/j.issn.1002-185X.20250219

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  Abstract:The cross piercing (RP) TC4-0.55 Fe titanium alloy seamless tube was taken as the research object. The microstructure was controlled by solid solution and aging treatments. The tensile properties at room temperature and impact properties at –20 ℃ were tested. The effects of microstructure evolution on mechanical properties were analyzed by scanning electron microscope, X-ray diffractometer, and transmission electron microscope. The results show that the size of α_C and the average grain thickness of α_L increase significantly, and the orientation and uniformity of the microstructure are also significantly enhanced. The tensile strength, yield strength, and elongation of RP samples are 904±1.23 MPa, 793±2.62 MPa and (14.2±0.72)%, respectively. The impact energy and impact toughness at –20 ℃ are 66.2±1.62 J and 82.7±1.03 J/cm², respectively. After solution and aging in the two-phase region, the tensile strength, yield strength, and elongation of STA910 sample increase to 984±8.92 MPa, 904±9.93 MPa and (16.2±0.93)%, respectively. The impact energy and impact toughness at –20 ℃ decrease slightly, but still maintain at 52.8±1.77 J and 64.9±1.78 J/cm², respectively. The α/β interface is increased by the precipitation of α_S and ω phases in the STA910 sample, which increases the dislocation slip and motion resistance and improves the segregation of alloying elements. The dual effects of grain boundary strengthening and solid solution strengthening are achieved, thus improving the strength and plasticity of the alloy. On the other hand, all TC4-0.55Fe alloys show excellent impact toughness. The fracture modes of the alloys are mainly ductile fracture and transgranular fracture. The coarsening of α phase grain size, the decrease in β phase stability, and the precipitation of α_S and ω phases in β_t lead to the decrease in impact properties of the alloys.

• Anisotropic Mechanical Behavior and Plastic Deformation Mechanisms of Commercially Pure Titanium with Different Initial Orientations

  Ma Chao, Shen Lu, Yang Shudong, Wang Yueyue, Li Zhiang, Guo Ying, Guo Xiaoqian, Zhang Chun

  2026,55(8):2050-2064 DOI: 10.12442/j.issn.1002-185X.20250222

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  Abstract:The anisotropic mechanical behaviors of TA1 commercially pure titanium (CP-Ti) rolled plates with two different initial orientations (bimodal texture and dispersed texture) under uniaxial loading, including stress-strain curves, tension-compression yield asymmetry, strain hardening, plastic strain ratio (r-value), and texture evolution were investigated using macroscopic mechanical property testing, microstructural characterization, and crystal plasticity modeling. The simulation results based on the VPSC-PTR model are well agreement with the experimental data. Compared to the plate with dispersed texture, the plate with bimodal texture presents more prominent anisotropy and tension-compression asymmetry, accompanied by more significant changes in the r-value and more intense texture evolution during deformation. Combining with the Schmid factor distribution, the relative activity of slip/twinning system, and critical resolved shear stress, the effect of initial texture on competition between slip and twinning during the deformation is clarified, revealing the influence mechanism of the initial orientation on the anisotropy of the rolled CP-Ti plates. The prismatic slip is the dominant mechanism of plastic deformation in CP-Ti. And extension twinning is more easily activated in plate with bimodal texture, while basal slip and pyramidal slip are more active in plate with dispersed texture, leading to different anisotropic characteristics. Moreover, the r-value of plate with bimodal texture is higher than that with dispersed texture during deformation, which is related to the decrease in activity of prismatic slip and the increase in activity of extension twinning.

>Special Issue：High Temperature Alloy

• Effect of Withdrawal Rate on Microstructure and Creep Performance of Directionally Solidified Mar-M247LC Superalloy

  Gan Yisheng, Wang Haiyang, Zhong Hong, Zhu Jiaxi, Li Bo, Feng Zhenyu, Li Shuangming

  2026,55(8):1865-1875 DOI: 10.12442/j.issn.1002-185X.20250488

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  Abstract:The effect of withdrawal rate on microstructure and creep performance of directionally solidified (DS) Mar-M247LC superalloy was investigated. Results show that an increase in withdrawal rate of DS specimens leads to a reduction in primary dendrite arm spacing (from 479 μm to 322 μm), and the average size of γ' precipitate decreases from 460 nm to 345 nm in interdendritic region and from 298 nm to 203 nm in dendritic core. In addition, the carbide morphology changes from blocky to script-like. The heat treatment leads to the formation of distinct cuboidal γ' precipitates. And the volume fraction of γ' precipitates in heat-treated microstructure has a significant increase compared to that in DS microstructure. The DS superalloy under the withdrawal rate of 40 μm/s exhibits elongated raft-like γ' structure with narrowed matrix channels and regular dislocation networks, synergistically prolonging creep rupture life to 96.6 h. Fractographic analysis confirms that the superalloy exhibits a transgranular ductile fracture mode, with cracks initiating at decomposed MC carbides.

• Effect of Gas Film Holes Processing Technique and Adjacent Hole Spacing on Oxidation Behavior of DD6 Single-Crystal Superalloy

  Hu Chunyan, Dong Meijing, Liu Xinling, Chen Xing, Liu Changkui

  2026,55(8):1907-1916 DOI: 10.12442/j.issn.1002-185X.20250472

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  Abstract:This study employed a field emission scanning electron microscope, an energy dispersive spectroscope, and ABAQUS finite element analysis to investigate the oxidation behavior of DD6 single-crystal superalloy at a constant temperature of 1000 ℃, focusing on the effects of various processed drilling processes and adjacent hole spacting. The results show that the trend in oxidation mass gain of the DD6 single-crystal superalloy processed by different drilling techniques with different adjacent hole spacting is relatively consistent, following the order: 0.75 mm>0.95 mm>0.55 mm>0.39 mm. Compared with drilling process, adjacent hole spacting emerges as the primary factor affecting oxidation mass gain. The high-temperature oxidation behavior differs between the two drilling processes. The change in microstructure and elemental redistribution in the recast layer produced by electrical discharge machining may cause a variety of elements at different states to react at different rates simultaneously. In contrast, after femtosecond laser processing, there is almost no recast layer on the inner wall of the holes, and the oxide layer forms directly on the single-crystal alloy matrix. Finite element analysis reveals that oxide layer developed on hole surfaces is primarily governed by shedding stress. As adjacent hole spacing increases, the areas of stress cancellation diminish, while shedding stress escalates to a peak under the adjacent hole spacing of 0.75 mm, at which point oxide film shedding is the most pronounced, and then decreases.

• Research on the Evolution Behavior and Micro-Zone Mechanical Properties of the Primary Carbides in Inconel 718 Superalloy Service Turbine Disk

  Zhang Yanlin, Chen Shuo, Jiang He, Dong Jianxin

  2026,55(8):1967-1976 DOI: 10.12442/j.issn.1002-185X.20250173

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  Abstract:Taking an Inconel 718 (GH4169) turbine disk with an accumulated service time of approximately 60 000 h from a specific model of aircraft as the research object, the microstructure evolution of various regions of the service turbine disk was investigated. Detailed characterization of the microstructure was conducted using research methods such as optical microscopy, scanning electron microscopy, electron probe, extraction phase analysis, inclusion scanner, and nano-indentation. The results show that after long-term service, there is no significant change in the strengthening phases γ' and γ' of the turbine disk. However, the quantity, size, and morphology of primary MC carbides from the center to the edge have noticeable changes. The content decreases from 0.166wt% to 0.106wt%, and the morphology gradually changes from sharp and regular blocky at the interface to irregular near-circular ones. The nano-hardness decreases, and there is a significant redistribution of elements, with elements Nb, Ti, and C released and diffused into the matrix. The primary MC carbides are prone to dissolution and decomposition during long-term service, leading to a decrease in concentration and hardness of the carbide elements. The diffusion of carbide-forming elements into the matrix may cause a disturbance to the comprehensive mechanical properties of the alloy during the long-term service performance.

• Effects of Initial Grain Morphology on Anisotropy of Microstructure and Mechanical Property in LPBF-Inconel 738 Alloy by Hot Isostatic Pressing

  Xu Jiayu, Gu Yuru, Ding Yutian, Tian Peng, Hua Shuli, Liu Bo, Gao Yubi, Hu Yong, Zhang Hongfei

  2026,55(8):1977-1986 DOI: 10.12442/j.issn.1002-185X.20250174

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  Abstract:Effects of initial grain morphology on anisotropy of microstructure and mechanical property in Inconel 738 alloy prepared by laser powder bed fusion (LPBF) under different scanning strategies after hot isostatic pressing (HIP) treatment were studied. The results show that the initial grain morphology is highly heritable. The initial grain morphology of Inconel 738 alloy formed by scanning strategy 90° (As-built 90 alloy) presents elongated columnar grains and irregular fine grains. After HIP treatment, the recrystallized grain morphology of HIP 90 alloy presents elongated columnar grains and a few equiaxed grains. The As-built Inconel 738 alloy formed by scanning strategy 67° (As-built 67 alloy) initially has short columnar and equiaxed grains, and the recrystallized grain morphology of HIP 67 samples shows similarly equiaxed and equiaxed grain morphology. The main reason is that the initial grain morphology determines the strain distribution. The strain distribution of As-built 90 samples is in the shape of “bar”, while that of As-built 67 samples is in the shape of “net”, and the strain distribution is more uniform. During HIP treatment, the strain concentration region preferentially provides nucleation location for recrystallized grains, which determines the morphology of recrystallized grains in HIP samples. The mechanical anisotropy of HIP 90 alloy is larger than that of HIP 67 alloy, which is mainly related to the grain morphology of HIP 90 alloy. The equiaxed grain morphology of LPBF-Inconel 738 alloy after HIP treatment requires appropriate LPBF process parameters.

• Microstructure and Tensile Properties of Mar-M247 Superalloy Turbine Blades

  Wei Liu, Yongfeng Sui, Yao Shichuan, Zhao Xinbao, Xu Jiachen, Fan Yunpeng, Liu Hao, Yue Quanzhao, Xia Wanshun, Gu Yuefeng, Zhang Ze

  2026,55(8):1999-2006 DOI: 10.12442/j.issn.1002-185X.20250194

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  Abstract:The Mar-M247 nickel-based superalloy turbine blade was investigated by tensile tests conducted from room temperature to 980 ℃. The microstructure, tensile properties, and fracture mechanisms of the alloy were analyzed. Results indicate that the alloy's microstructure primarily consists of γ phase, flower-like γ′ phase, γ/γ′ eutectic structure, and carbide phases. The alloy strength initially increases and then decreases with increasing temperatures. At low temperatures, fracture exhibits a mixed mode dominated by transgranular fracture with intergranular fracture as a secondary component, where cracks preferentially initiate at carbide/matrix interfaces. When the temperature reaches 980 ℃, the fracture mechanism transitions to microvoid coalescence-induced ductile fracture, accompanied by an increase in elongation to 6.4%. Deformation mechanism analysis reveals that stacking fault shearing dominates in the low-temperature region (<400 ℃), forming Lomer-Cottrell (L-C) dislocation locks. The intermediate temperature range (400–760 ℃) displays Portevin-Le Chatelier (PLC) effects coupled with intermediate-temperature brittleness. Above 760 ℃, widening matrix channels and increased stacking fault energy promote a synergistic interaction between antiphase boundary (APB) shearing and Orowan bypassing mechanisms, leading to a significant decrease in deformation resistance.

• Effects of Gas Regulation on the Characteristics of Nickel-Based and Titanium Alloy Powders Prepared by EIGA

  Zhang Lichong, Chen Hao, Liu Yufeng, Zheng Liang, Xu Wenyong, Li Zhou, Zhang Guoqing

  2026,55(8):2007-2016 DOI: 10.12442/j.issn.1002-185X.20250198

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  Abstract:Electrode induction-melting gas atomization (EIGA) is a crucial technique for producing ultra-high-purity metal powders, as it is a crucible-free powder production method. This study focused on the nickel-based superalloy FGH96 and the titanium alloy TC4, and the effects of atomization pressure and gas temperature on the particle size, morphology, and hollow powder content of the alloys were investigated. The study combined atomization experiments with powder characterization. The results show that at a gas temperature of 25 ℃, increasing the atomization pressure from 2.5 MPa to 4.0 MPa reduces the median particle size (D₅₀) from 96.3 μm to 75.5 μm. The sphericity reaches 0.9805 at an atomization pressure of 3.5 MPa. The powder volume porosity also exhibits a trend of first increasing and then decreasing. At an atomization pressure of 4.0 MPa, when the gas temperature increases to 100 ℃, the powders are further refined, with the D₅₀ values for FGH96 and TC4 powders decreasing to 63.8 and 86.0 μm, respectively. The gas heating effect is more pronounced for the superalloy powders. As the gas temperature rises, the powder sphericity of the superalloy remains unchanged, while the powder sphericity of the titanium alloy increases slightly. The powder volume porosity of the superalloy slightly increases. Due to differences in viscosity, surface tension, and density between the two alloy melts, powder characteristics such as particle size and morphology exhibit distinct variation trends. This study provides a theoretical basis for the customization of powder preparation processes for different types of alloys.

>Materials Science

• Microstructure and Properties of 921A Steel Joints Prepared by Local Dry Underwater Oscillating Laser Welding

  Zhu Jialei, Wang Yuke, Zeng Caiyou, Li Shougen, Zhu Wenlei, Shao Mingxing, Yang Zilong

  2026,55(8):1849-1857 DOI: 10.12442/j.issn.1002-185X.20250473

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  Abstract:In response to the need for in-situ repair of deep cracks in a naval ship, a 4 mm-deep 30° U-shaped groove was prepared on 921A steel. Groove filling experiments were conducted using local dry underwater oscillating laser wire feed welding under the conditions of air and shallow water. The microstructure and properties of the welds were analyzed. The results indicate that sound welds without significant defects are obtained in both air and shallow water. Owing to the effective shielding gas protection within the local dry cavity and the rapid cooling effect underwater, the shallow water weld exhibits a bright white surface with densely distributed fish-scale patterns. The air weld includes a higher fraction of acicular ferrite, whereas the rapid cooling in water promotes the formation of lath martensite. The main alloying elements under both environments exhibit a smooth transition near the fusion lines with good metallurgical bonding. However, due to the higher cooling rate in the shallow water compared with that in air, there is a greater fluctuation in elemental distribution, along with higher contents of Si, Mn, and Mo and a slightly lower Cr content in the shallow water weld. The shallow water weld shows higher overall hardness than the air weld, though the hardness distribution trends across different zones are similar in both cases. Tensile tests reveal that fracture occurs in the base metal under both environments, with the tensile strength and yield strength ranking as follows: shallow water weld>air weld>base metal. However, electrochemical corrosion tests indicate that the shallow water weld has inferior corrosion resistance compared to the air weld.

• Effect of H₂ on 8YSZ Coatings Prepared by Arc Plasma Torch

  Geng Chuanwen, Zhao Peng, Su Yi, Fan Zihao, Wu Xi

  2026,55(8):1858-1864 DOI: 10.12442/j.issn.1002-185X.20250436

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  Abstract:The thermal barrier coatings (TBCs) are prepared using spraying technique of 8YSZ particles. In this process, H₂ is often added to the plasma torch discharge system. In order to study the effect of H₂ content on plasma discharge, this study emplyed particle velocity capture diagnostics, optical emission spectroscopy, and finite element simulation to validate the relationship between H₂ content and coating quality. The results indicate that adding H₂ increases the temperature and velocity of plasma, which in turn improves the efficiency and in-flight velocity of molten 8YSZ particles. However, when the H₂ /(Ar+H₂) is increased to 50%, the instability of arc root disturbs the arc plasma discharge, posing a challenge to maintaining the physical state of the in-flight particles. With an increase in H₂ flow rate, the coating quality shows a trend of first increasing and then decreasing, with the optimal flow rate ratio being H₂/(Ar+H₂)=37.5%. The findings of this work can serve as a theoretical guidance and reference for the preparation of TBCs via plasma.

• Synthesis and Performance Characterization of Mo₂BC Bulk Prepared by Spark Plasma Sintering

  Liu Xiaoyu, Zhi Lei, Xia Haoyu, Feng Gong, Shao Botao, Liu Jing, Zhang Shengnan, Li Jianfeng, Zhang Pingxiang

  2026,55(8):1889-1896 DOI: 10.12442/j.issn.1002-185X.20250540

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  Abstract:The high-purity Mo₂BC bulk was synthesized via spark plasma sintering (SPS) technique. Results show that the Mo₂BC bulk prepared by optimized SPS process exhibits exceptional structural homogeneity, with a Vickers hardness of 19 GPa. This considerable mechanical hardness is attributed to the strong covalent bonding network within the Mo₂BC crystal structure. Simultaneously, magnetic and electrical characterization confirms that the Mo₂BC bulk has superconductivity with a transition temperature of 7.8 K and a high upper critical field of 6.3 T. The coexistence of such notable mechanical properties and robust superconducting characteristics in Mo₂BC bulk reveals a promising candidate for advanced applications under extreme conditions. This study not only provides crucial insights into the non-centrosymmetric bulk materials, but also establishes SPS as an efficient route for developing novel superconductors with high hardness.

• Effect of Initial Orientation on Microstructure Evolution of Zr-Sn-Nb Alloy During Asynchronous Rolling

  Wang Shang'an, Zhang Conghui, Zhou Jun, Zhu Wenguang, Liu Shuaiyang, Zhang Jin, Li Rui, He Xiaomei

  2026,55(8):1943-1950 DOI: 10.12442/j.issn.1002-185X.20250256

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  Abstract:Asynchronous rolling reduces rolling force through the cross-shear effect, significantly influencing the plastic deformation behavior of zirconium alloys, and serves as an effective approach to optimize texture characteristics in Zr-Sn-Nb alloys. In this study, Zr-Sn-Nb alloy sheets were subjected to asynchronous rolling at a speed ratio of 1.13 along the RD-TD (0° sample) and RD-ND (90° sample) directions. By combining electron backscatter diffraction and intra-grain misorientation axis (IGMA) analysis, the effects of initial orientation and deformation amount on microstructure evolution, slip system activation, and deformation mechanisms during asynchronous rolling were investigated. The results demonstrate that with the increase in deformation, both oriented samples exhibit significant grain refinement and a progressive rise in the fraction of low-angle grain boundaries. Throughout rolling, the 0° sample retains a bimodal texture, whereas the 90° sample undergoes a texture transition from <0001>∥TD to a bimodal texture. IGMA analysis reveals that prismatic <a> slip dominates the early deformation stage in both samples. As strain accumulates, competition arises between prismatic <a> slip and basal <a> slip. In the 0° sample, prismatic <a> slip remains the predominant deformation mode, with negligible contributions from other mechanisms. In contrast, plastic deformation in the 90° sample is cooperatively accommodated by {102} twinning, prismatic <a> slip, basal <a> slip, and pyramidal <a> slip.

• Microstructure Evolution of Zr/Re Co-modified PtAl Coatings During Isothermal Oxidation

  Li Yuntong, Xiao Junfeng, Gao Song, Tang Wenshu, Li Yongjun, Nan Qing, Li Yifan, Xu Xiaobu, Ma Wei, Wu Xiaohu

  2026,55(8):1951-1957 DOI: 10.12442/j.issn.1002-185X.20250160

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  Abstract:The Zr/Re co-modified PtAl coating was fabricated by electroplating Pt vacuum diffusion annealing and composite electroplating Ni-Zr/Re layer+arc ion plating Al layer vacuum diffusion annealing. The isothermal oxidation experiment was carried out at 1100 ℃ for 200 h. The phase composition and microstructure of the as-annealed coating and the oxidized coating were characterized by SEM, XRD and EPMA, and the distribution law of the modified elements and the evolution law of the coating microstructure during oxidation were investigated. The results show that the Re-rich precipitates dispersed in the coating aggregate and grow during oxidation and form volatile oxide Re₂O₇. The Zr solid-solved in the coating co-precipitates with the Ta element diffused into the coating from the substrate alloy, and some Zr enters the Al₂O₃ scale to form Zr-rich oxides, reducing the growth rate of the Al₂O₃ scale. In addition, with the mutual diffusion of elements between the coating and the substrate, the β phase in the coating undergoes martensitic transformation. The precipitates in the mutual diffusion zone change from plate-like to particle-like, and the coexistence relationship of Cr-rich precipitates and Re, Cr and W-rich precipitates is found in the secondary reaction zone of the coating.

• Dynamic Mechanical Behavior and Low-Temperature Mechanical Properties of Porous CoCrNi Medium-Entropy Alloy

  Wei Lai, Wang Xiaohua, Liu Jie, Wang Yifei, Ma Shengguo, Wang Zhihua

  2026,55(8):1958-1966 DOI: 10.12442/j.issn.1002-185X.20250166

  Abstract(6) HTML(0) PDF(2.64 M)( 4)

  Abstract:Porous CoCrNi medium-entropy alloy (MEA) with porosity of 60.6%–78.1% and pore size of 1.8–2.4 mm were prepared by powder sintering-dissolution method. Results show that the pore distribution is uniform, and the metallurgical bonding is good. The dynamic compression test results show that the material has a significant strain rate strengthening effect, and the impact resistance is the best at strain rate of 500 s^–1. The yield strength increases by 52.8% (from 22.9 MPa to 35.0 MPa) with the increase in strain rate from 200 s^–1 to 800 s^–1. The dynamic yield strength increases by 25% compared with the quasi-static yield strength. The energy absorption value reaches 35.4–14.5 MJ/m³ (6.6%–14.0% higher than the quasi-static result), and the maximum ideal energy absorption efficiency is close to 0.9. At the same time, under the condition of low temperature (–100 ℃), the elastic modulus and platform stress are increased by 2.4%–10.5% and 2.5%–9.8%, respectively, compared with those at room temperature. The energy absorption value is 41.3–15.2 MJ/m³, which is twice that of magnesium alloy foam, and the maximum ideal energy absorption efficiency is 0.8. In summary, the porous CoCrNi MEA has both dynamic strengthening and low-temperature strengthening characteristics, and it has good energy absorption capacity and high ideal energy absorption efficiency, showing significant application potential in the field of actual working conditions and extreme environments.

• Effect of Al-Si Filler Wires on the Microstructure and Mechanical Properties of Cold Metal Transfer Welded AlSi10Mg Alloy Joints Fabricated Using Powder Bed Fusion Laser Beam/Metal

  Qiao Jiutong, Wu Defan, Cui Li, Ma Lixia, Wu Xu, Guo Xingye, He Dingyong

  2026,55(8):2017-2027 DOI: 10.12442/j.issn.1002-185X.20250200

  Abstract(7) HTML(0) PDF(6.02 M)( 4)

  Abstract:The cold metal transfer (CMT) butt welding was conducted on AlSi10Mg alloy thin sheets prepared by the powder bed fusion laser beam/metal (PBF-LB/M) technique using two types of filler wires, including ER4043 (Al-Si5) and ER4047 (Al-Si12). The effects of the two wires on weld geometry, porosity, microstructure, and mechanical properties of the welded joints were evaluated. Results indicate that the adding ER4043 wire effectively reduces porosity rate and pore size of the weld metal. In contrast, the ER4047 wire exhibits improved mechanical performance. The ultimate tensile strength of joints welded with ER4047 wire reaches 211.7 MPa, representing a 6.7% increase compared to the 198.4 MPa achieved with ER4043 wire. The average microhardness of the ER4047 weld (76.8 HV) increases by 15.5% compared to that of ER4043 weld. These findings suggest that the higher Si content in ER4047 filler wire is more conducive to achieving superior joint properties. Microstructural analysis attributes this enhancement to a combination of solid solution strengthening, fine grain strengthening, texture strengthening, nanoscale Si precipitation, and the load-bearing contribution of the eutectic Si network.

• Microstructure and Mechanical Property of High-Purity Tantalum Target Billets with Multi-pass Rolling Reduction

  Wang Yin, Cao Xudan, Li Guipeng, Yuan Yubo, Wu Yanfang

  2026,55(8):2065-2073 DOI: 10.12442/j.issn.1002-185X.20250236

  Abstract(10) HTML(0) PDF(3.19 M)( 4)

  Abstract:To fabricate high-purity tantalum target billets with uniform grain size, preferential orientation, and homogeneous hardness distribution, a series of high-purity tantalum target billets were prepared by electron beam melting and multi-pass rolling technique. The effects of rolling modes (cold rolling/hot rolling) and multi-pass rolling reduction on the microstructure, and mechanical properties of tantalum target billets were investigated. The results indicate that compared with that prepared by hot rolling, the sample prepared by cold rolling exhibits smaller and more uniform grain size. Under cold rolling condition, the multi-pass rolling reduction decreases from 20% to 2%, and the grain size and standard deviation of the tantalum target billets change significantly, varying from 46.01 μm to 58.92 μm. Meanwhile, the proportion of (100) and (111) crystal planes gradually increase, while the proportion of (110) crystal plane rapidly decreases. When the multi-pass rolling reduction is 2%, the growth of the (110) crystal plane in the tantalum target blank sample is certainly inhibited, a high proportion of (100)-(111) mixed random texture is obtained, and the Vickers hardness of the tantalum target increases to 147.68 HV. These research findings provide an important reference for the development of high-quality tantalum target billets.

>Reviews

• Research Status and Progress on Preparation and Purification of Niobium Metal by Pyrometallurgy

  Jiang Dongsheng, Zhao Zhuan, Tang Huimin, Zhang Huan, Wang Ruifang, Che Yusi, He Jilin

  2026,55(8):1917-1928 DOI: 10.12442/j.issn.1002-185X.20250397

  Abstract(4) HTML(6) PDF(1.26 M)( 7)

  Abstract:As a strategic critical metal, niobium is widely used in the fields of aerospace, nuclear industry, and superconductors owing to its superior properties. With the requirement of sustainable development, the energy consumption in niobium melting processes has attracted increasing attention. Green, low-carbon, and energy-saving practices have become the new development direction. In addition, microelectronics technology requires high-purity niobium as a sputtering target material. Although niobium with a purity of up to 5N has been achieved, a low-cost high-purity technique is still challenging. This review summarized a variety of pyrometallurgical methods for the preparation and purification of crude niobium. As a traditional method for producing crude niobium, the key challenge of thermal reduction is how to reduce energy consumption. As a technique with industrial propects, molten salt electrolysis has been developed into a variety of methods, but the efficiency needs to be further improved. In addition, some new purification techniques are constantly emerging, such as fully-automated melting technique assisted by the digital twin and artificial intelligence. In the future, a variety of technical means will be combined to purify niobium metal. This review also briefly introduced the current status of niobium recovery and further explored the full lifecycle of niobium based on the concept of urban mine, to provide direction for achieving niobium recycling.

• Research Progress of GH4099 Superalloy Prepared by Laser Powder Bed Fusion

  Huo Chuanteng, Su Haijun, Wang Lin, Yang Peixin, Guo Yinuo, Gao Hongliang

  2026,55(8):2074-2083 DOI: 10.12442/j.issn.1002-185X.20250239

  Abstract(3) HTML(5) PDF(1.58 M)( 6)

  Abstract:As a representative γ'-strengthened nickel-based superalloy, GH4099 is widely used in hot-end components under extreme service environments such as aviation, aerospace, and nuclear due to its excellent high-temperature performance, thermal stability, corrosion resistance, as well as fatigue resistance and fracture toughness. Laser powder bed fusion (LPBF) technique has effectively solved the technical bottlenecks such as prolonged processing cycle, insufficient process synergy, low material utilization, and high cost in the forming process of complex components by the traditional manufacturing technique. This review presents a comprehensive overview of the recent advancements in LPBF technique for the formation of GH4099 and delved into various aspects of GH4099 superalloys prepared by LPBF, including its technical principles, solidification defects, microstructure, and high-temperature mechanical properties. Furthermore, it focused on the influence of powder characteristics, process parameters, post-treatment techniques (including heat treatment and hot isostatic pressing technique), and other factors on the solidification defects and high-temperature mechanical properties of GH4099 superalloys prepared by LPBF. Finally, it summarized and outlined the application potential and development trends of this technique in future manufacturing.

• Research Progress of Double Glow Plasma Surface Alloying Technology on TiAl Alloy

  Chen Lin, Han Dong, Hu Na, Hu Dan, Yang Lijing, Gao Guangrui

  2026,55(8):2084-2098 DOI: 10.12442/j.issn.1002-185X.20250557

  Abstract(3) HTML(6) PDF(2.04 M)( 8)

  Abstract:TiAl alloy has important application value in aerospace and other high-temperature structural components due to its low density, high specific strength, and excellent creep resistance at high temperature. However, the high-temperature oxidation resistance of TiAl alloy in the environment above 750 ℃ is poor and the service life of some high-temperature service components under the condition of hot corrosion and high-temperature wear is reduced, which restrict its application. Double glow plasma alloying surface technology is an important way to enhance the surface protection ability without changing the overall performance of the substrate. The basic mechanism of the double glow plasma surface alloying technology was reviewed. The unit infiltration, dual infiltration, multi-component co-infiltration, and the composition and structure of infiltration coatings on high temperature oxidation resistance, hot corrosion resistance, and wear resistance were discussed. Finally, it outlined the future developing trends in the view of theoretical research, preparation process, and engineering applications.

• Catalytic Degradation of Wastewater by Amorphous Alloys： Current Status， Influencing Factors， and Modification Strategies

  Wang Haiqun, Li Chunyan, Yang Longpeng, Zhang Shuyan, Su Zhengrui, Li Chunling, Li Xiaocheng, Kou Shengzhong

  2026,55(8):2099-2116 DOI: 10.12442/j.issn.1002-185X.20250155

  Abstract(8) HTML(0) PDF(3.33 M)( 7)

  Abstract:With the rapid development of human society, the discharge of various types of sewage has increased year by year, and environmental problems such as water pollution have become increasingly serious. Seeking effective sewage treatment methods has become an urgent need. Due to its excellent surface activity, low oxidation-reduction potential, and outstanding catalytic degradation performance, amorphous alloys are regarded as effective catalysts for solving various types of wastewater, such as dyeing wastewater. Currently, extensive research has been conducted on the treatment of wastewater containing organic pollutants such as dyes and pesticides, as well as inorganic pollutants such as heavy metals and acid-base salts. However, the degradation mechanism of amorphous alloys varies greatly depending on the type of wastewater and the amorphous alloy system, resulting in different degradation rates. Therefore, selecting suitable amorphous alloy components and appropriate material modification methods is crucial for achieving efficient degradation of wastewater. This review summarized the conventional techniques for wastewater treatment, the characteristics and potential of amorphous alloys, their applications in wastewater treatment, and the existing problems. It also reviewed the influence of various chemical parameters and other factors on the catalytic performance of amorphous alloys, as well as various material modification methods, aiming to provide valuable references for the research of new catalysts.

Online First

• Grain growth and defect control strategy of large module single crystal superalloy turbine blades

  Mu Hao, Meng Xiangbin, Liu Jide, Zhang Chaowei, Zou Mingke, Wang Liang, Wang Meng, Fan Dahua, Ma Yuejiao, Chu Zhaokuang, Meng Jie, Liang Jingjing, Zhao Yunsong, Liu Chenguang, Zhou Yizhou, Li Qiang, Wang Ruichun, Zhu Chongwei, Li Jinguo

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250559

  Abstract(57) PDF(3.40 M)(37)

  Abstract:With the promotion and application of new large-sized single crystal superalloy turbine blades with complex air-cooled structures in aviation engines, the demand for single crystal turbine blades has sharply increased, leading to the prominent problem of cost reduction and efficiency improvement of single crystal turbine blades. At present, the growth and defect control technology of large module single crystal superalloy blades is one of the effective ways to reduce costs and increase efficiently of single crystal blades, and it is also an important development direction for the production technology of new single crystal turbine blades. Therefore, combining numerical simulation and experimental verification, the directional solidification process of single crystal superalloy turbine blades with different size modules will be studied to explore the behavior of single crystal growth, the formation law of stray grain, and corresponding control methods. The results show that during the directional solidification process, the liquid isotherm presents an "upward convex" shape, which leads to the inner side of the platform reaching the nucleation condition first, inducing the formation of stray grains in the platform. As the withdrawal rate and module size increase, the degree of "upward convex" of the liquid isotherm will significantly intensify, leading to an increased probability of stray grain formation. By adding graphite regenerator at the center of the module, the uniformity of the temperature field can be effectively improved and the inclination degree of the isotherm can be decreased, which can significantly reduce the probability of stray grain formation and improve blade qualification rate, thereby the problem of cost reduction and efficiency improvement for single crystal blades can be solved.

• Study on the Tensile Creep Behavior of Swaged W-Y?O? Alloy at High Temperatures of 1400–1600°C

  Tu cheng ming, Wang jian bao, Feng fan, Zhao dong, Wang zi jie, Jin yu zhong, Lian you yun, Liu xiang

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250572

  Abstract(32) PDF(3.00 M)(32)

  Abstract:The tensile creep behavior of Y?O?-dispersion-strengthened tungsten (W-Y?O?) alloys prepared via powder metallurgy and high-temperature rotary swaging was investigated at temperatures ranging from 1400 to 1600°C under pressures of 150 to 180 MPa. Changes in grain structure, second-phase particles, and dislocations before and after creep were analyzed using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM).Experimental results indicate that the creep performance of rotary-forged W-Y?O? alloys surpasses that of rolled pure tungsten, with a steady-state creep rate ranging from 8.22×10e-7 to 1.76×10e-4—two orders of magnitude lower than rolled pure tungsten. The superior creep performance of rotary-forged W-Y?O? primarily stems from the pinning of grain boundaries and dislocation motion by nanoscale and submicron-sized Y?O? particles, coupled with the suppression of diffusion creep due to thelarger grain aspect ratio.As temperature and creep stress increase, the agglomeration pinning effect of second-phase particles weakens, reducing the grain aspect ratio. The proportion of creep mechanisms dominated by grain boundary slip due to atomic diffusion and recrystallization gradually increases. However, dislocation motion control remains the primary mechanism in the W-Y?O? matri

• Differences in Recrystallization Behavior between the Surface and Center Layers of Hot-Rolled Thick Plate of 5xxx Aluminum Alloy

  Fang Zhijie, Wang Yujing, Mo Man, Mei Lin, Xu Lei, Xiao Zhengbing

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250573

  Abstract(34) PDF(2.97 M)(34)

  Abstract:A 5xxx series aluminum alloy hot-rolled thick plate with a final rolling temperature of 300?°C was used to systematically investigate the effects of different annealing processes (300–500?°C, 0.5–8?h) on its microstructure, mechanical properties, and electrical conductivity. The results show that increasing the annealing temperature significantly promotes recrystallization in the surface layer, while recrystallization in the center proceeds more slowly. Due to the high dislocation density and sufficient dynamic recovery introduced during hot rolling, continuous recrystallization via subgrain coalescence and growth dominates in the surface layer during annealing. In contrast, discontinuous recrystallization prevails in the center owing to its lower stored energy and fewer nucleation sites. After annealing at 450?°C for 2?h, the recrystallization fraction reaches 66.6?% at the surface but only 18.9?% in the center. With increasing annealing temperature, hardness and strength decrease, while elongation and electrical conductivity increase. Holding time has a relatively minor influence on mechanical properties, and 2?h is identified as the optimal duration. This study clarifies the mechanism underlying the difference in recrystallization behavior between the surface and center of hot-rolled thick plates during annealing, providing a theoretical basis for optimizing annealing processes.

• Influence of Heat Treatment on the Microstructural Evolution and High-Temperature Mechanical Behavior of TiAl-4822 Alloy Produced by Electron Beam Powder Bed Fusion

  Zhang Xuezhe, Wang Yifan, Zheng Hao, Niu Jingzhe, Liu Haiyan, Jia Liang, Liu Nan, Yuan Xinbo

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250578

  Abstract(44) PDF(9.68 M)(42)

  Abstract:To investigate the influence of heat treatment–induced microstructural evolution on the high-temperature mechanical behavior of Ti–48Al–2Cr–2Nb (TiAl-4822, at.%) alloy at 750 °C, specimens were fabricated via electron beam powder bed fusion (EB-PBF) and subsequently subjected to various heat treatment conditions to obtain distinct microstructures. The as-fabricated sample exhibited a heterogeneous bimodal structure composed of coarse γ bands and fine-grained duplex regions. After heat treatment at 1330 °C for 0.5 h followed by furnace cooling (FC), the alloy developed a homogeneous duplex microstructure with slightly coarsened grains. Increasing the heat treatment temperature to 1380 °C resulted in pronounced grain growth and the formation of a fully lamellar structure. With rising temperature, α? phases tended to segregate along interlamellar or intergranular regions, establishing the typical Blackburn orientation relationship with the γ phase. Mechanical testing revealed that hardness increased with heat treatment temperature, whereas both tensile strength and ductility at 750 °C decreased compared with the as-fabricated condition. The as- fabricated sample demonstrated superior high-temperature mechanical performance, achieving a tensile strength of 654.67 ± 17.01 MPa and an elongation of 42.5 ± 2.29%, primarily due to the fine γ grains and dense intragranular lamellae formed during rapid solidification. During heat treatment, the α? and γ phases coarsened through orientation-dependent growth to minimize interfacial energy, leading to lamellar thickening. The resulting coarsened lamellae and α? phase enrichment at grain boundaries and interlamellar interfaces served as preferential sites for crack initiation and propagation, thereby reducing ductility. This study elucidates the intrinsic correlations among heat treatment, microstructure, and mechanical behavior in EB-PBF TiAl-4822 alloy, providing valuable insights into tailoring the microstructure and optimizing the high-temperature performance of γ-TiAl alloys through thermal processing

• Study on the high-temperature creep behavior of single-crystal molybdenum alloys

  He Zijian, Yu Bintao, Dou Yankun, He XinFu, Zhang Lin

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250582

  Abstract(45) PDF(2.23 M)(32)

  Abstract:New reactor materials serve for a long time Under extreme loads and high temperatures. Creep resistance is the key service performance. In this paper, thermal creep experiments with different stresses (170-245MPa) were carried out at 1100K for the candidate material single crystal Mo-14Re alloy for advanced reactors. The creep time of the single crystal Mo-14Re alloy was obtained from 10 h to 780 h, and it was found that the creep of the single crystal Mo-14Re alloy conformed to the standard creep law, and the stress index n was 11.7. The creep mechanism is dislocation reinforcement, and with the increase of creep time, dislocation will form three dislocation derived structures: dislocation wall (substructure), dislocation network and dislocation cell. The above research provides a scientific basis for the research and development and safe service of advanced reactor materials.

• Anisotropy of Extrusion Texture and Adiabatic Shear Sensitivity of TC4 Alloy Bar

  Weikang Fu, Tianyuan Gong, Yi Li, Chenxing Zheng, Xinlong Dong

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250586

  Abstract(50) PDF(3.18 M)(32)

  Abstract:The microstructural orientation and texture developed during titanium alloy processing have significant effects on its dynamic mechanical behavior, particularly on adiabatic shear characteristics. In this study, the compression anisotropy and adiabatic shear behavior of the α+β TC4 alloy bar were investigated under high strain rates along the extrusion direction (ED) and transverse direction (TD) using a Split Hopkinson Pressure Bar (SHPB) apparatus. The localized deformation evolution and mechanisms were analyzed through Digital Image Correlation (DIC) and Electron Backscatter Diffraction (EBSD) techniques. The results reveal that the α-hcp phase in the extruded TC4 bar exhibits an axially symmetric cylindrical fiber texture. The yield strength in the TD is significantly higher than that in the ED; however, the TD shows greater adiabatic shear sensitivity and a higher tendency for adiabatic shear band (ASB) formation. EBSD analysis indicates that the specific crystallographic orientations induced by the extrusion texture influence yielding behavior by affecting the Schmid factors of dislocation slip systems, thereby leading to deformation anisotropy. The extrusion texture along the ED aligns most grains favorably for the activation of the basal slip system in the α-hcp phase, which has a lower critical resolved shear stress (CRSS), resulting in a lower dynamic yield strength compared with the TD. Meanwhile, the more homogeneous deformation among grains and the weaker thermal effect along the ED contribute to its lower adiabatic shear sensitivity. These findings provide insights into the influence of microstructural orientation and texture on adiabatic shear behavior in titanium alloys, offering guidance for texture control and design strategies to enhance resistance to adiabatic shear failure.

• Progress in neutron studies on the magnetic structures of rare earth magnetic materials

  LIU Dan, Ren Jianyu, Chen Weiqiang, Zheng Yusha, QIXING, XI Jianfeng

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250592

  Abstract(61) PDF(3.30 M)(36)

  Abstract:Rare-earth magnetic materials hold an indispensable strategic position in high-tech fields such as permanent magnets and magnetic refrigeration, owing to the unique characteristics of their 4f electrons: strong spin-orbit coupling, high atomic magnetic moments, and rich electronic energy levels. The multifaceted competitive mechanisms among electron exchange interactions, magnetic multipolar interactions, and crystal field effects in these materials present fundamental challenges to elucidating magnetic phase transition mechanisms and quantum excitation behaviors. Neutron scattering technology, distinguished by its sensitivity to magnetic moments, exceptional penetration capability, and ability to distinguish light elements, serves as a pivotal technique for revealing the microscopic mechanisms of magnetic structures in rare-earth systems. This technique has achieved breakthrough progress in areas including coercivity optimization of rare-earth permanent magnets and regulation of the magnetic entropy change in magnetocaloric materials. This article systematically reviews the fundamental principles and methodologies of neutron scattering technology alongside its cutting-edge applications in investigating magnetic structures within rare-earth magnetic materials, including rare-earth-transition-metal compounds, rare-earth frustrated magnets, and rare-earth low-dimensional magnets. The review aims to provide a foundational reference for advancing research on magnetic structures in rare-earth systems.

• Process Optimization for Preparing Uniform and Dense Tungsten Coatings on Throat Liners by CVD 备注（英文论文，RMME-2025-0058）

  XIE ZHENG, wang, tanchenwen, yuxiaodong, ningxianjin

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250595

  Abstract(34) PDF(2.50 M)(30)

  Abstract:Tungsten"s distinctive physical and chemical properties make it a highly suitable material for rocket applications. Chemical vapor deposition (CVD) is a promising technique for applying uniform tungsten coatings to complex-shaped components (e.g., rocket engine throat liner). This study adapts a previously established low-pressure CVD model for tungsten, enabling its application under atmospheric pressure conditions to deposit high-performance coatings on rocket engine throat liners. We investigate the influence of three distinct reactor configurations—a straight-tube inlet, an integrated gas distribution device, and a combination of a distribution device with a flow guide baffle—on the reactor"s flow dynamics, thermal field, species concentration, and deposition kinetics. Numerical and experimental results demonstrate that the configuration incorporating both a distribution device and a baffle eliminates vortices within the liner region by promoting radial gas diffusion, thereby significantly improving flow field uniformity. This optimized design not only improves the uniformity of the deposition rate on the throat insert, but also slightly enhances the utilization efficiency of tungsten hexafluoride. This work provides a theoretical foundation for designing CVD systems for highly uniform tungsten coatings and offers a practical solution for their engineering application.

• Corrosion behavior of a Zr-xSn-0.35Fe-0.15Cr alloy in high-temperature,high-pressure oxygenated water

  zhaoduo, xiaoxiangyi, xushitong, yaomeiyi, hulijuan, xieyaoping, zhangpeng, heguanze, zhoubangxin

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250599

  Abstract(33) PDF(4.18 M)(34)

  Abstract:Zirconium alloys are extensively utilized as cladding materials for fuel elements in water-cooled nuclear reactors due to their low thermal neutron absorption cross-section, high thermal conductivity, excellent corrosion resistance, and good compatibility with UO2. Small Modular Reactors (SMRs) represent a significant direction for future nuclear energy. However, the simplified design of small water-cooled reactors, which often lack hydrogen addition and oxygen removal facilities or have limited deoxygenation capacity, leads to an elevated concentration of Dissolved Oxygen (DO) in the primary circuit coolant. This increased DO level can adversely affect the corrosion resistance of zirconium alloy cladding. Sn is an important alloying element for zirconium. Nevertheless, research on the influence of DO on the corrosion resistance of zirconium alloys with varying Sn content is scarce. Therefore, this study investigates the corrosion behavior of zirconium alloys with different Sn contents in water at 360 °C/18.6 MPa with different DO concentrations, aiming to provide a theoretical basis and guidance for developing zirconium alloy cladding materials for water-cooled SMRs. To explore the effect of Sn content on the corrosion behavior of zirconium alloys in oxygen-enriched water, corrosion tests were conducted on three Zr-xSn-0.35Fe-0.15Cr (x=0.5, 1.0, 1.5, wt%) alloys and a Zr-4 alloy in a dynamic autoclave at 360 °C/18.6 MPa with a DO concentration of 1000 μL/L. The microstructure and phase composition of the alloys and their oxide films were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Raman spectroscopy. The results indicate that the second-phase particles (SPPs) in the Zr-xSn-0.35Fe-0.15Cr alloys are primarily composed of two types: fcc-Zr(Fe,Cr)2 and hcp-Zr(Fe,Cr)2. With increasing Sn content, the size and the Fe/Cr atomic ratio of the SPPs increase, while their area fraction decreases. During the 290-day corrosion period, the corrosion kinetics transitioned from a cubic rate law to a parabolic or power-law rate law. An increase in Sn content led to an earlier transition time in the corrosion kinetics and a higher post-transition corrosion rate. The corrosion kinetics shifted from parabolic to power-law behavior, indicating a degradation in corrosion resistance. However, all the Zr-xSn-0.35Fe-0.15Cr alloys exhibited significantly superior corrosion resistance compared to the Zr-4 alloy in the 1000 μL/L DO water environment. This paper discusses the underlying mechanism of how Sn content influences the corrosion behavior in oxygen-enriched water from the perspectives of SPPs oxidation and the microstructural evolution of the oxide film.

• The Corrosion Behavior of Pre-oxidized 56Cu-22Ni-12Fe-8Al-2La Anode Alloy in Low Temperature Molten Electrolyte for Aluminum Electrolysis

  Du Juan, Bao Shengzhong, Yang Shaodan, Zhou Yanjun, Zhuang Yuwei, Cao Shuguang

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250607

  Abstract(36) PDF(2.13 M)(34)

  Abstract:The corrosive behaviors of unoxidized and pre-oxidized 56Cu-22Ni-12Fe-8Al-2La anode alloys are investigated in Na3AlF6-K3AlF6-AlF3-Al2O3 electrolytes for aluminum electrolysis at 800℃. Results show that the oxide layer formed on the pre-oxidized alloy at 800 °C under O2 atmosphere is mainly oxides of aluminum, nickel, iron, copper, and lanthanum. After 3h aluminum electrolysis, the corrosion products formed on unoxidized anode alloy is a tri-layered structure and the discontinuous and porous oxide layer provides a connected channels during electrolysis, allowing direct electrolyte penetrate into the metal matrix for about 320 μm thickness. The corrosion oxide layer formed on pre-oxidized anode alloy is about 190 μm thickness. The out and inner oxide layer includes a continuous Ni/Fe/Al/Cu-rich (mainly NiFe2O4, CuAlO2) oxides. The middle layer containing of a dense and continuous NiFe2O4 with a thickness about 15 μm. A small amount of electrolyte appears in the oxide layer and penetrate into the metal matrix. The pre-oxidized alloy exhibited a better corrosion resistance and stability in comparison with that unoxidized alloy during aluminum electrolysis. The electrochemical performances testing of the metal anodes in molten salt for aluminum electrolysis are carried out and the corrosion mechanism of the alloys are also investigated.

• Tribological Behavior of HVOF-Sprayed NiCrBSi Coatings at Elevated Temperatures

  Du PengCheng, Yang RenTao, Wu ZhengJiang, Fan MingZhen, Zhang Yan, Yuan ZhenNan, Chen TongZhou

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250615

  Abstract(36) PDF(3.53 M)(39)

  Abstract:A NiCrBSi coating was fabricated on 304 stainless steel substrate using high-velocity oxygen-fuel (HVOF) spraying. The friction and wear behaviors of the coating were systematically investigated at room temperature (RT), 200 °C, 400 °C, and 600 °C to reveal the influence of elevated temperatures on its wear mechanisms. The effects of temperature on the microstructure and mechanical properties of the coating were analyzed by scanning electron microscopy (SEM) and high-temperature microhardness testing, respectively. The morphology and chemical composition of the wear tracks were characterized using white light interferometry and Raman spectroscopy. The results indicate that the NiCrBSi coating exhibits a distinct crystallization exothermic peak at approximately 505 °C. Above this temperature, the crystallinity and microstructure of the coating were significantly improved. As the temperature increased, both the porosity and microhardness of the coating generally decreased, with a relatively gradual decline below 505 °C and a sharp drop beyond it. The combined effect of mechanical action between the coating and the counterpart ball and the high-temperature environment induced oxidation during friction, generating oxides such as NiO, Cr?O?, and NiCr?O?. At temperatures below 505 °C, the high-temperature environment led to a certain reduction in the friction coefficient. With a further increase in temperature, the lubricating effect of the oxides further contributed to the decrease in the friction coefficient. Meanwhile, the wear rate of the coating continuously increased with temperature, rising from 2×10?? mm3/(N·m) at RT to 11.3×10?? mm3/(N·m) at 600 °C. At room temperature, the dominant wear mechanism was fatigue wear. As the temperature increased to 600 °C, the marked decrease in coating hardness led to the generation of substantial debris, making abrasive wear the predominant mechanism.

• A Review and Future Perspectives of Wire Arc Additively Manufactured Titanium Matrix Composites

  Lu Jinglin, Chen Zixuan, Xue Aitang, Zhang Quanli, Meng Zhibin, Zhang Xiaoyong

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250619

  Abstract(32) PDF(4.78 M)(39)

  Abstract:Titanium matrix composites (TMCs) have emerged as promising candidates for lightweight, high-strength structural components. Their appeal lies in the potential to surpass the performance limits of conventional homogeneous alloys through strategic design of reinforcements in terms of their type, morphology, and spatial distribution. Concurrently, wire arc additive manufacturing (WAAM) offers a novel paradigm for fabricating complex TMC structures with high material utilization and shortened processing routes, leveraging its dual advantages of near-net shaping and rapid solidification. This review systematically summarizes the current state of research on wire arc additively manufactured TMCs, with a focused discussion on three critical aspects: geometrical integrity, microstructural characteristics, and mechanical properties. The analysis indicates that by optimizing process parameters such as heat input and current mode, and employing auxiliary processes including preheating and maintaining temperature. can effectively mitigate defects such as porosity and cracking, thereby improving dimensional accuracy. The inherent rapid solidification of WAAM, combined with the introduction of reinforcing phases, facilitates grain refinement and enables microstructural control. Furthermore, the strategic design of architectural features such as laminated or network-like structures can lead to significant enhancement in material strength. Future research should focus on a deeper integration of process-microstructure-property relationships to accelerate the broad adoption of this technology in the manufacturing of high-performance components.

• Integrated Analysis of As-Cast Microstructural Characteristics and the Homogenization Treatment for GH3536 Superalloy

  Liu Yue, Jiang He, Yao Zhihao, Dong jianxin

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250621

  Abstract(34) PDF(5.45 M)(30)

  Abstract:In this study, the as-cast microstructure of a GH3536 electroslag ingot, produced via a vacuum induction melting plus electroslag remelting duplex process, was systematically examined using multiple characterization techniques. These included optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), extracted phase analysis, X-ray diffraction (XRD), and thermodynamic calculations. Furthermore, the microstructural evolution following homogenization heat treatment and the results of hot compression simulations were analyzed to identify an appropriate homogenization process for the alloy. The results demonstrate that molybdenum (Mo) is the primary segregating element in the alloy. In addition to the austenitic matrix, the electroslag ingot contains two types of carbides: M??C?, enriched with chromium (Cr), and M?C, enriched with Mo. After homogenization heat treatment at 1180?°C for 48?h, the coarse secondary phases were largely dissolved, and elemental segregation was significantly reduced. Consequently, the homogenized alloy exhibited excellent hot workability.

• Temperature-Dependent Modeling of High-Temperature Fatigue Crack Growth Behavior in GH4710 Superalloy

  Chen Youhong, Lan Bo, Sun Xing, Li Kai

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250623

  Abstract(34) PDF(4.10 M)(32)

  Abstract:Aiming at the high-temperature fatigue failure risk of GH4710 alloy turbine disks for aero-engines, the fatigue crack growth behavior of the alloy at 750℃, 815℃ and 850℃ was systematically studied, the temperature influence mechanism was revealed, and a temperature-dependent model was established. The results show that grain boundary oxidation weakening is the dominant factor for accelerated crack growth at high temperatures. When the temperature increases from 750℃ to 850℃, the fatigue crack growth rate of the alloy increases significantly, the fatigue life decreases by 74.7%, and the fracture mechanism transforms from transgranular dominance to intergranular dominance. The range of 815~850 ℃ is the critical mutation temperature range for fatigue performance, and below this temperature, the alloy has a wider stress intensity factor range ( ΔK) and better crack growth resistance. Based on the Paris equation, an Arrhenius-type temperature correction term was introduced to establish the model: da/dN=9.783×10^(-7)×exp?(-3557.068/T) (ΔK)^3.183 (T is absolute temperature, K). Within the range of ΔK =20~65 MPa·m?·?, the error between the model predictions and experimental data is less than 10%, which can accurately characterize the fatigue crack growth behavior of the alloy in the temperature range of 750~850℃. This study provides theoretical support for the damage tolerance design, high-temperature service life prediction and critical temperature early warning of GH4710 alloy turbine disks.

• Influence of Ce addition on the microstructure and mechanical properties of Al-Cu-Mn-Mg alloy

  Yu Wen-tao, Zhang Han, Zhang Weixia, Lv Yadong, Yang Haiyan, Xue Yanqing, Hao Qitang

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250625

  Abstract(29) PDF(7.03 M)(23)

  Abstract:This study systematically investigated the influence of cerium (Ce) additions on the microstructure and mechanical properties of Al-Cu-Mn-Mg alloys through multi-scale characterization techniques including optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results reveal that the addition of Ce leads to the formation of two distinct Ce-containing intermetallic compounds. The first is the primary Al20Ti2Ce phase formed during solidification, which has caused the grain coarsening due to consumption of the effective grain-refining element Ti in Al melt. The second Ce-containing phase is Al16Cu4Mn2Ce, which forms through a eutectic reaction at the final stage of the solidification process. This phase is unstable at high temperatures and undergoes a phase transformation into Al24Ce3Cu8Mn and Al20Cu2Mn3 during heat treatment, it means that Al16Cu4Mn2Ce can not dissolve like Al2Cu, which prevents an increase in the concentration of Cu and Mn in the Al matrix, thereby leading to a low degree of supersaturation. Furthermore, the addition of minor Ce can retard the phase transformaiton from θ"" to θ" in the Al matrix. Therefore, the main strengthening phase is still the θ"" phase in the Ce-containing alloy while θ" phase in 0Ce alloy after the same heat treatment. Changes in the microstructure and phase composition directly affect the mechanical properties of alloys, the ultimate tensile strength and yield strength decrease by 87 MPa and 42 MPa respectively when the Ce content increases from 0 to 0.3 wt%, and the elongation decreases by 50% compared with 0Ce alloy.

• Novel Cobalt-Based Superalloys: Compositional Design, Microstructure-Property, and Application Progress

  Wang Xiao, Luo Guoqiang, Wei Qinqin, Dai Xiangping, Shen Qiang

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250629

  Abstract(44) PDF(2.79 M)(34)

  Abstract:Conventional cobalt-based superalloys are limited in high-temperature properties due to the lack of coherent strengthening phases. The discovery of the L12-structured γ′-Co3(Al, W) phase has initiated the research on novel cobalt-based superalloys. This paper systematically reviews the recent progress in this field, covering composition design, processing techniques, microstructure, mechanical properties, and application status. The compositional strategies, including multi-component alloying and density reduction, are elaborated. Combined with typical cases, the breakthroughs of additive manufacturing technology in suppressing segregation and cracking are discussed. Furthermore, strengthening models are introduced to quantitatively analyze the influence of γ′ phase characteristic parameters on strength. In addition, the key mechanisms for improving high-temperature oxidation and hot corrosion resistance are deeply discussed. Finally, the application progress of these alloys in aero-engine hot-end components and high-temperature tools and molds is summarized, and future development directions regarding microstructural stability and engineering fabrication are proposed.

• Research Progress on Laser-cladded High-Entropy Alloy Coatings

  Wang Ruixin, Zhang Yong, Zhang Yitian, Liu Jiahui, Ma Lei, Han Xiaoliang, Wang Hui, Song Kaikai

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250639

  Abstract(42) PDF(1.94 M)(32)

  Abstract:High-entropy alloys demonstrate outstanding comprehensive performance due to their revolutionary multi-component design concept, making them ideal materials for achieving structural-function integration. The laser cladded high-entropy alloy coatings combines the performance advantages of high-entropy alloys with the technical advantages of laser cladding, achieving a high-quality balance among surface performance, mechanical performance, and functional performance, and showing great potential for engineering applications. This paper starts from the "process-microstructure-performance" relationship and the intrinsic mechanism. The preparation methods and optimization strategies are summarized. The microstructure, performance and performance improvement mechanisms under single and coupled conditions are revealed. The potential application scenarios and the problems that need to be solved urgently in current applications and the future development direction are disccused.

• Elevated shear strength of aged Sn58Bi solder joints under low density current stressing

  Gong Zhiwen, Li Wangyun, Lin Yichun, Hu Fei, Cai Huihong, Yue Wu

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250644

  Abstract(38) PDF(9.37 M)(39)

  Abstract:This study investigates the impact of low density current stressing on the shear performance of thermally aged Sn58Bi solder joints and elucidates the underlying mechanisms. Cu/Sn58Bi/Cu joints were subjected to isothermal aging at 120 °C for different durations (0 h, 240 h, 480 h, 720 h, 960 h, 1200 h, 1440 h, 1680 h) and tested under current densities of 0, 1×103, 2×103, and 3×103 A/cm2. The results indicate a non-monotonic "rise-fall" trend in the shear strength of aged joints with increasing current density. Notably, a maximum strength increase of 12.85 % was observed in joint aged for 480 h under a current density of 2×103 A/cm2, comparing with the unaged and current-free ones. This strengthening behavior at 480 h is primarily attributed to two mechanisms: (1) the applied current promotes the multiplication of geometrically necessary dislocations (GNDs), elevating strength via dislocation strengthening; and (2) higher current density facilitates an increase in the subgrain fraction of the Bi phase, which effectively impedes dislocation motion. Conversely, at higher current densities, shear strength decreases due to Joule heating, which induces thermal mismatch and compromises the interfacial bonding between the interfacial intermetallic compounds (IMC) layer and the solder matrix. These findings provide theoretical insights for the reliability assessment of low-temperature solder joints in electronic packaging.

• High-Temperature Extrusion-Induced Dynamic Precipitation of Nano-Sized α-Mn Phase Synergistically Enhances the Strength and Corrosion Resistance of Mg-Zn-Mn-Gd-Ca Alloy

  Zhi Gejie, Zhang Jinghuai, Bao Rirong, He Yuying, Qiu Xin, Yang Qiang, Xie Jinshu, Liu Shujuan, Zhang Xiaobo

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250647

  Abstract(40) PDF(5.28 M)(28)

  Abstract:To address the challenge of synergistically improving the strength and corrosion resistance of magnesium alloys, the effects of extrusion temperatures (360 °C and 380 °C) on the microstructure, mechanical properties, and corrosion behavior of the Mg-2Zn-0.8Mn-0.7Gd-0.3Ca alloy were systematically investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscattered diffraction (EBSD), scanning Kelvin probe force microscopy (SKPFM), tensile tests, immersion tests, and electrochemical measurements. The results show that the most significant microstructural effect of increasing the extrusion temperature to 380 °C is the remarkable promotion of dynamic precipitation of α-Mn nanoparticles. These precipitated phases pin the grain boundaries and inhibit grain growth. Through the combined effects of second-phase strengthening and grain refinement strengthening, the yield strength of the alloy is increased from 202 MPa to 244 MPa. Meanwhile, after stable immersion in 3.5 wt% NaCl solution, the surface film resistance of the alloy is enhanced from 2238 ohm cm2 to 4811 ohm cm2, and the corrosion rate is reduced from 1.325 mm·y-1 to 0.839 mm·y-1. The improved protective performance of the film may be associated with the precipitation of dispersed nano-sized α-Mn particles. By simply adjusting the hot extrusion process, this study achieves the simultaneous enhancement of strength and corrosion resistance, providing a new perspective for the design of high-strength and corrosion-resistant magnesium alloys.

• Effect of different scratching speeds on nano-scratched γ-TiAl under water lubrication

  zhoubaocheng, huangqianqian, Liushiwei, caohui, ruizhiyuan, fengruicheng

  Available online:June 01, 2026  DOI: 10.12442/j.issn.1002-185X.20250648

  Abstract(33) PDF(1.86 M)(27)

  Abstract:Due to the excellent high-temperature and lightweight properties of γ-TiAl alloys, they have great application potential in the aerospace field. However, the inherent brittleness of γ-TiAl alloys poses significant challenges to precision machining. Water lubrication can reduce the processing temperature, which can help solve the problems of friction, heat accumulation, and tool wear faced by γ-TiAl alloys during processing, as well as reduce crack initiation and overcome the inherent brittleness of γ-TiAl alloys. This makes water lubrication a very promising method in the processing of γ-TiAl alloys. Therefore, a molecular dynamics (MD) simulation was used to construct a nano-scratching model of single-crystal γ-TiAl alloy under water lubrication, and the effect of scratching speed on the scratching force, substrate temperature, plastic deformation, and surface quality of single-crystal γ-TiAl alloy during nano-scratching was systematically studied under water lubrication. As the scratching speed increased, both the scratching force and temperature increased significantly. However, under water layer lubrication, when the water layer thickness was 1nm, the substrate temperature fluctuation was small, showing a good cooling effect. When the scratching speed reached 400m/s, the plastic deformation of the workpiece surface was significantly aggravated, the accumulation of chips increased, and the surface roughness decreased.

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