2026,Volume 55, Issue 4

>2026 Advanced Titanium Alloys

• Orthogonal Optimization of Solution Treatment and Aging Process for TB18 Titanium Alloy and Toughness Regula-tion Mechanism

  Gao Huixian, Li Ke, Shao Shan, Yang Haoxue, Li Qinqin, Zhao Yanru, Luo Wenzhong, Feng Yong, Lei Qiang, Liu Xianghong

  2026,55(4):841-855 DOI: 10.12442/j.issn.1002-185X.20250284

  Abstract(36) HTML(109) PDF(5.16 M)( 190)

  Abstract:To investigate the effect of solution treatment and aging process parameters on the microstructure and mechanical properties of TB18 titanium alloy, process optimization research was conducted based on the mixed-level orthogonal experiment design of factor levels. Results show that through range analysis, the significance order of process parameters is determined as follows: solution cooling method>solution temperature>aging time>aging temperature>solution time. Considering the strength-ductility matching and engineering application requirements, the benchmark parameters are selected as solution time of 1 h, solution cooling method of air cooling (AC), aging temperature of 525 °C, and aging time of 4 h. Furthermore, the effects of solution temperature in the range of 790–870 °C on the impact toughness and micro-fracture characteristics of the alloy were studied. The results reveal that the larger the area of shear lip and fibrous zone, and the smaller the area of radiation zone, the better the toughness of the alloy. With the increase in solution temperature, the length of secondary cracks on the fracture surface increases, the number of dimples increases, and the toughness is enhanced. Based on the collaborative optimization of strength and toughness, the optimal heat treatment process for TB18 alloy is determined as 870 °C/1 h, AC+525 °C/4 h, AC.

• Combustion Behavior and Microstructure of Ti-Al-Mo-Zr-Sn-W Alloy After Laser Ignition

  Wang Xinyu, Mi Guangbao, Chen Yisi, Sun Ruochen, Qiu Yuehai, Tan Yong

  2026,55(4):856-868 DOI: 10.12442/j.issn.1002-185X.20250204

  Abstract(24) HTML(55) PDF(3.39 M)( 141)

  Abstract:The combustion behavior of Ti-Al-Mo-Zr-Sn-W alloy (TC25G) was studied in a high-temperature and high-speed air flow environment using the laser ignition method combined with ultra-high temperature infrared thermometer, scanning electron microscope, X-ray diffractometer, and transmission electron microscope. The burn-resistant performance of TC25G and TC11 alloys was compared. Meanwhile, the microstructural characteristics, crystal structure, and formation mechanism of the combustion products of TC25G alloy were analyzed in detail. The results show that the high-temperature and high-speed air flow promotes combustion within the air flow temperature range of 200–400 °C and the air flow velocity range of 0–100 m/s. The combustion path advances along the direction of the air flow. The combustion of TC25G alloy mainly relies on the diffusion of the oxygen and the expansion of the combustion area caused by the movement of the melt. Based on the microstructure and composition of combustion product, it can be divided into the combustion zone, the melting zone, and the heat affected zone. During combustion, the formation of microstructures is closely correlated with the behavior of alloying elements and their selective combination with O. The major oxidation products of Ti are TiO and TiO₂. The oxides formed by Mo and W hinder the movement of the melt during the combustion. Al and Zr tend to undergo internal oxidation. Al₂O₃ precipitates on the surface of ZrO₂, forming a protective oxide layer that inhibits the inward diffusion of O. Moreover, the element enrichment at the interface between the melting zone and the heat affected zone increases the melting point on the solid side, hindering the migration of the solid-liquid interface.

• Effect of Channel Segregation on Microstructure and Mechanical Properties of Ti45Nb Alloy Wire

  Shang Jinjin, Yang Hui, Bai Huiwen, Wu Yulun, Zhao Xiaohua, Lei Qiang, He Tao, Liu Xianghong, Zeng Weidong

  2026,55(4):869-876 DOI: 10.12442/j.issn.1002-185X.20250443

  Abstract(22) HTML(54) PDF(2.60 M)( 142)

  Abstract:The effects of channel segregation on the macro- and micro-scale chemical composition, microstructure, hardness, and tensile deformation behavior of Ti45Nb wires were investigated. The results show that wires with severe channel segregation exhibit a macroscopic chemical composition identical to those without segregation, and 3D X-ray imaging result also reveals no abnormalities. After annealing, both types of wires exhibit an equiaxed single-phase microstructure with comparable grain sizes, suggesting that channel segregation has negligible influence on the macroscopic composition and grain size. Metallographic examination reveals that channel segregation manifests as spot-like features in the transverse section and band-like structures in the longitudinal section. EDS analysis identifies these regions as Ti-enriched segregations, with a Ti content higher than that of the surrounding matrix by approximately 4.42wt%. Compared to segregation-free wires, those containing extensive channel segregation demonstrate a 15.5% increase in ultimate tensile strength and a 12.3% increase in yield strength, but suffer a reduction in elongation and reduction of area by 19.8% and 18.9%, respectively. Furthermore, the mechanical properties of wires with segregation show significant fluctuations. Fractographic analysis reveals a larger fracture surface area in segregated wires. Severe dislocation pile-ups occur at the interfaces of these segregated regions, initiating microcrack nucleation. This promotes rapid crack propagation of the Ti45Nb wire, leading to a significant decrease in plasticity and reduction of area.

• Research on High-Precision Thermoplastic Phenomenological Constitutive Models of TC4 Titanium Alloy

  Qi Chang, Niu Yazhe, Chen Xiaolan, Wang Nan, Yang Shu, Pei Lianzheng

  2026,55(4):941-949 DOI: 10.12442/j.issn.1002-185X.20240787

  Abstract(23) HTML(38) PDF(1.83 M)( 142)

  Abstract:To accurately predict the thermoforming process of TC4 titanium alloy, the high-temperature rheological behavior of TC4 titanium alloy was investigated, and a high-precision thermoforming phenomenological constitutive model was developed. Firstly, high-temperature tensile tests of TC4 titanium alloy were conducted at 973-1123 K with strain rates of 0.01-1 s^-1. Based on the experimental data, two constitutive models were established: an Arrhenius constitutive model with strain compensation and a modified Johnson-Cook constitutive model. Sparrow search algorithm (SSA) was employed to optimize the model parameters. Finally, the predictive abilities of the phenomenological constitutive models for TC4 titanium alloy were assessed using statistical analysis. The results indicate that the Arrhenius constitutive model achieves relatively high predictive accuracy despite limited experimental data. However, it has a restricted parameter optimization space. In contrast, the modified Johnson-Cook constitutive with lower predictive accuracy, offers a larger parameter optimization space. The SSA-optimized modified Johnson-Cook constitutive model provides a good fit with experimental results, serving as a solid foundation for high-precision numerical simulations of TC4 titanium alloy thermoforming.

• Formation Mechanism of Bright-Band Defect of TC18 Alloy During Forging

  Liu Xianghong, Wang Tao, Ren Xiaolong, Fu Jie, Zhu Bin, Cheng Liang, Wang Kaixuan

  2026,55(4):950-958 DOI: 10.12442/j.issn.1002-185X.20240804

  Abstract(34) HTML(62) PDF(4.23 M)( 174)

  Abstract:A systematical analysis of the macrostructure, microstructure, composition, and crystal orientation of the bright-band defect was conducted by OM, SEM, and EBSD methods, as well as Gleeble tests, and the formation mechanism of bright-band defect of forged TC18 alloy was studied. The results show that the bright-band defects in the center of TC18 alloy forging stocks correspond to β cube-grains with the size of around 100 mm. During the forging process, an inhomogeneous distribution of temperature and equivalent strain in the forging stocks is caused by adiabatic heating, which is an important reason for the microstructural heterogeneity. The large β cube-grains are formed due to the repeated compression along the orthogonal direction, which results in continuous strengthening of the <100> texture in the center of the forging stocks, and the merging of <100> grains with similar orientations. Through annealing treatment and compression along diagonal direction, it is possible to effectively reduce and avoid bright-band defects in TC18 alloy.

• Dynamic Recrystallization Behavior of Multi-modal α Phases in TC4 Alloy During Hot Deformation

  Zhang Xuehua, Zhang Lei, Li Yuluo, Yang Yiming, Zhao Yongqing

  2026,55(4):959-970 DOI: 10.12442/j.issn.1002-185X.20250330

  Abstract(22) HTML(29) PDF(13.74 M)( 132)

  Abstract:The hot deformation response and dynamic recrystallization behavior of two representative initial microstructures (a fully lamellar microstructure and an equiaxed-lamellar bi-modal microstructure) were systematically investigated in a wide-width hot-rolled bloom TC4 alloy using a Gleeble thermal simulation testing system at deformation temperature of 1173 K and strain rates of 10 and 0.01 s?1. Meanwhile, a coupled phase-field and crystal plasticity model was developed to simulate the stress-strain distribution and dislocation density evolution in the α/β phases under different initial microstructural conditions. This model was used to examine how initial microstructure configurations influence the dynamic recrystallization behavior of the α phase. The results indicate that under a high strain rate of 10 s?1 and the deformation of 60%, the fully lamellar microstructure undergoes significant dynamic recrystallization in the α phase, resulting in a uniform fine-grained structure with an average grain size of 0.58 μm. In contrast, in the bi-modal structure, only part of the lamellar α phase exhibits localized recrystallization, while the equiaxed α phase primarily undergoes dynamic recovery. Compared with the fully lamellar structure, the bi-modal microstructure requires greater deformation to activate dynamic recrystallization in both the equiaxed and lamellar α phases. This discontinuous recrystallization behavior is attributed to differences in stress-strain distribution between the equiaxed and lamellar α phases during concurrent deformation. These differences influence dislocation accumulation and subgrain formation, ultimately altering the driving force conditions for dynamic recrystallization.

• Effect of Microstructure on Hydride Transition of TC4 Titanium Alloy

  Zhang Tong, Wang Qian, Weng Hanbo, Yan Shiyu, Huang Sensen, Qi Min, Yan Feng, Ma Yingjie, Lei Jiafeng, Yang Rui

  2026,55(4):971-979 DOI: 10.12442/j.issn.1002-185X.20250308

  Abstract(29) HTML(40) PDF(7.32 M)( 137)

  Abstract:The diffusion behavior of hydrogen in lamellar and bi-modal TC4 alloys was investigated through electrochemical hydrogenation combined with multi-scale characterization techniques. The results show that after electrochemical hydrogen charging, the diffusion surfaces of lamellar and bi-modal samples present a gradient distribution of hydrogen concentration, and the thickness of the hydrogen diffusion layer of two samples is similar. The volume fraction of hydride in the diffusion surface of the lamellar sample is larger, hydrides preferentially form at the α/β interface and grow in the form of twin pairs into the α phase. In the case of the bi-modal sample, due to the relatively large equiaxed α grain size, hydrides cannot fill the entire α grain. Different hydride variants alternate in nucleation and growth near the α/β interface. TEM analysis results indicate that the hydrogenation nucleation in both microstructure samples presents a multi-level structural transformation mechanism regulated by stacking faults.

• Effect of Heat Treatment on the Microstructure and Mechanical Properties of Mn-Containing β-Type γ-TiAl Alloy

  Chen Chuanyi, Hao Junjie, Shu Lei, Chen Bo, Niu Hongzhi, Li Xiaobing, Liu Kui

  2026,55(4):980-993 DOI: 10.12442/j.issn.1002-185X.20240784

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  Abstract:Manganese, serving as a cost-effective and potent stabilizer of the β-phase, plays a pivotal role in the development of economically viable and easily deformable β-type γ-TiAl alloys. In this investigation, we focused on a low-cost and easily deformable Ti-44Al-3Mn-0.4Mo-0.4W-0.1B-0.1C alloy (at%), which was rolled into 12 mm-diameter bars by vacuum induction melting and conventional hot rolling techniques. The effects of high-temperature treatments at 1270, 1220, and 1170 °C on the microstructure and mechanical properties of the alloy bars were studied by EPMA, TEM, and EBSD. The results show that the microstructure of the alloy contains γ, α₂, and β_o phases after heat treatment. Decreasing the temperature of high-temperature treatment under identical aging conditions significantly reduces the α₂/γ lamellar content within the alloy. Moreover, both the size of the lamellar colonies and the spacing between lamellae exhibit pronounced reductions as the treatment temperature decreases. The tensile performance tests demonstrate that as the temperature of high-temperature treatment decreases, the tensile strength at room temperature and 800 °C of the alloys with different microstructures declines. At room temperature, the elongation of the heat-treated alloys shows a trend of first increasing and then decreasing, and the values are all within the range of 0.5%–1.0%. However, at 800 °C, significant variations in elongation are observed in the alloys. Specifically, an increase in equiaxed γ phase content correlates with enhanced alloy elongation. Compared to samples treated at 1270 °C, those treated at 1220 °C exhibit a 280% increase in elongation, while those treated at 1170 °C show a 480% increase. This enhancement is attributed to the improved deformability of the equiaxed γ phase at elevated temperatures. Additionally, greater activation of dislocations within the β_o phase occurs, while the γ/γ and α₂/γ interfaces impede the movement of twins and dislocations. This study provides a comprehensive discussion on the evolution behavior and patterns of different heat-treated alloys, emphasizing their correlation with mechanical properties.

• Influence of Electric-Assisted Forming Process on Microstructure and Tensile Properties of TC4 Titanium Alloy

  Peng Heli, Zu Qingming, Liu Le, Liu Haijian, Liu Baisong, Li Ping, Yan Siliang, Xue Kemin

  2026,55(4):994-1002 DOI: 10.12442/j.issn.1002-185X.20240785

  Abstract(22) HTML(30) PDF(6.02 M)( 136)

  Abstract:By applying different current frequencies during the tensile process of the aerospace TC4 titanium alloy, the flow stress of the material is increased and its maximum yield strength is reduced. The microstructural evolution of the material after electrification and the fracture morphology of the samples were observed. The influence of the electric-assisted forming process on the tensile process was analyzed in combination with the tensile test results. The experimental results show that with the increase in pulse current density, the content of the α phase decreases significantly, while the β phase content increases substantially, and the grain size begins to increase. A small amount of martensitic phase suffers transformation during cooling, resulting in fine acicular α′ phase. As the current density further increases, the primary α phase disappears completely, the β phase grows further, and the size of the transformed α′ phase increases. During tensile deformation, the sample temperature rises sharply at the moment when current is applied. It continues to increase during the tensile process, with rising increment until it reaches a peak value at the moment of fracture. The peak temperature increases with the rise in current density and pulse frequency. As the current density increases, the flow stress of TC4 titanium alloy gradually decreases, and its ductility improves. SEM and TEM results show that with the increase in current density, the dimples in the tensile fracture surface of TC4 titanium alloy sheets become significantly deeper, presenting a honeycomb-like appearance, with tear ridges around the dimples, indicating a typical ductile fracture feature. Compared with that after high-temperature and room-temperature tensile tests, the dislocation density inside the material after electric-assisted tensile tests is significantly reduced, with dislocations appearing more straight and some dislocations orderly aligned in a certain direction, indicating that pulse current promotes dislocation motion.

• Effect of Clad Rolling Process on Microstructure and Properties Evolution of Fine-Grain TC4 Alloy Sheet

  Zhu Wenguang, Ru Huixin, Wang Qinbo, Zhang Conghui, Wang Jian, Wang Xin, Pu Chaobo, Ma Qiang, Zhang Pinghui

  2026,55(4):1003-1012 DOI: 10.12442/j.issn.1002-185X.20250099

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  Abstract:The microstructure evolution of TC4 alloy plates with α martensitic as primary microstructure in dual-phase region during clad rolling and annealing were investigated. The relationship between microstructure evolution (grain size, texture) and strength of the alloy was discussed. The results show that β-quenched alloy exhibits fine lamellae α′ martensite which displays multi-scale and multi-variant distribution. The grain of β-quenched alloy is significantly refined with average grain size of 0.89 μm and <0001>//ND of Basal texture forms after two-phase cross rolling. However, a mixed structure, consisting of fine recrystallized grains and coarse deformed grains, is observed. During annealing process, the rolled samples undergo continuous static recrystallization, resulting in the formation of fine equiaxed grain (approximately 1.86 μm at 720 ℃). Meanwhile, annealing treatment do not change the texture type, while the intensity of Basal texture is slightly enhanced. The strong Basal texture makes the Schmidt factor of prismatic <a> slip close to each other along the direction of TD and RD, which results in the decrease in strength difference between transverse and longitudinal direction. The strength of the sheet decreases with the increase in annealing temperature, which is due to the synergistic effect of the increase in grain size and the decrease in dislocation density. The result shows that the fine grained TC4 alloy with Basal texture can be fabricated by using α+β phase cross rolling and annealing, which provides a theoretical basis and technical support for the preparation of fine-grain titanium alloy plates for aerospace applications.

• Research on White Blocks of TB18 Ultra-High Strength and Toughness Titanium Alloys

  Xin Shewei, Liu Xianghong, Feng Jun, Zhou Wei, Zhang Xinquan, Li Bo, Li Shaoqiang, Wang Tao

  2026,55(4):1013-1018 DOI: 10.12442/j.issn.1002-185X.20250181

  Abstract(21) HTML(35) PDF(5.26 M)( 141)

  Abstract:The white blocks of TB18 high Mo equivalent metastable β ultra-high strength and toughness titanium alloy were studied. The alloy which was forged in the two-phase region and then solid solution and aging treatment in β region. The formation mechanism and elimination methods of white blocks were analyzed by mechanical property testing, microstructure observation, and further heat treatment experiments. The results indicate that the white blocks in TB18 titanium alloy are β matrix without any precipitation of α phase, with low hardness, high plasticity, and high impact toughness. The reason for the formation of white blocks is not related to the distribution of β-stable elements in the alloy, but mainly caused by the forging process. White blocks can be weakened or eliminated from the macroscopic structure by optimizing forging or heat treatment processes, such as increasing solubility, pre-aging, and extending aging time. However, from a more detailed microstructure analysis, the white blocks in TB18 titanium alloy cannot be completely eliminated but can only be reduced in size, which is determined by the characteristics of the TB18 alloy. The results of this study have a fundamental guiding role in improving the preparation process and optimizing the microstructure of TB18 alloy, and also produce important reference significance for the microstructure and performance analysis of similar alloys.

• Research Progress on Multi-scale Microstructure Design and Strengthening-Toughening Mechanisms of Discontinuously Reinforced Titanium Matrix Composites

  Cong Guanghui, Chen Zhibin, Cui Xiping, Huang Lujun, Wang Zhiqi, Zhang Yuanyuan, An Qi, Chen Xin, Wang Shuai, Geng Lin

  2026,55(4):1078-1089 DOI: 10.12442/j.issn.1002-185X.20250305

  Abstract(83) HTML(49) PDF(10.57 M)( 176)

  Abstract:Discontinuously reinforced titanium matrix composites (DRTMCs) exhibit advantages such as light weight, high strength, and heat resistance, demonstrating broad application prospects in aerospace, consumer electronics, and other fields. Inspired by the multi-scale architectures of natural materials, the design of DRTMCs has evolved from uniformly distributed single reinforcements to architecture reinforcement configurations, and further to the coordinated design and regulation of multi-scale reinforcement architectures coupled with hierarchical titanium matrix. This progression has enriched their microstructure, leading to the formation of multi-scale heterogeneous structures. Such structures fully leverage synergistic strengthening mechanisms to enhance strengthening efficiency. Moreover, these composites effectively avoid strain localization to ensure favorable plasticity while maintaining excellent damage resistance. This review summarizes typical configuration design strategies and their evolutionary pathways in DRTMCs, elucidates the underlying strengthening-toughening mechanisms, and proposes future research directions based on current advancements to advance the application of high-performance titanium matrix composites in critical fields.

• Research Progress on Variant Selection and Microstructural Characteristics of Martensitic Transformation of Titanium Alloys

  Chuan Kaiyang, Zhang Chongle, Zhang Jinyu, Liu Gang, Sun Jun

  2026,55(4):1090-1101 DOI: 10.12442/j.issn.1002-185X.20250135

  Abstract(28) HTML(44) PDF(10.76 M)( 157)

  Abstract:In the practical production and processing of titanium alloys, variant selection frequently occurs during martensitic transformation due to various influencing factors. This preferential behavior causes the crystallographic orientation distribution of α′/α″ phases to deviate from theoretical equiprobability, consequently affecting material anisotropy and mechanical properties. Studies reveal that quenching-induced β→α′ transformation exhibits weak variant selection characteristics. In contrast, stress-induced β→α″ transformation often demonstrates strong variant selection effects with a consistent preference for orientations accommodating maximum external stress. Simultaneously, characteristic self-accommodating morphologies are commonly observed in α′/α″ martensitic microstructures, including triangular, V-shaped, Z-shaped, trapezoidal, and parallel clusters formed by aggregated variants. The emergence of these self-accommodating clusters is one of the critical mechanisms underlying variant selection effects. This paper systematically elaborates on the characteristics and formation mechanisms of martensitic transformation and elucidates the intrinsic nature and influencing factors of variant selection. By integrating the phenomenological theory of martensite and statistical analysis of inter-variant interfaces, the formation mechanisms of self-accommodating microstructures and interface distribution associated with variant selection effects are analyzed comprehensively. Finally, current challenges and future research priorities in this field are identified.

• Research Progress on Equiaxed Microstructure Regulation of Additively Manufactured Ti-6Al-4V Alloy

  Wang Nan, Dai Guoqing, Chang Hui

  2026,55(4):1102-1114 DOI: 10.12442/j.issn.1002-185X.20250345

  Abstract(32) HTML(47) PDF(11.67 M)( 177)

  Abstract:Ti-6Al-4V alloy is widely used in aerospace, biomedical, and other fields due to its excellent specific strength, corrosion resistance, and biocompatibility. However, rapid solidification and complex thermal cycling during additive manufacturing often lead to the formation of coarse columnar β grains in titanium alloys, resulting in anisotropic mechanical properties and reduced fatigue performance. Achieving equiaxed microstructure control is crucial for improving the comprehensive properties of additively manufactured titanium alloys. This work reviewed recent advances in achieving equiaxed microstructures of Ti-6Al-4V (TC4) alloy through microalloying, composite fabrication, external field assistance, and heat treatment. The influence mechanisms of α-stabilizing elements, β-stabilizing elements, external field-assisted techniques, and heat treatment processes on the microstructure and mechanical properties of Ti-6Al-4V alloy were discussed. Furthermore, future research directions were outlined, focusing on precise microstructure control, process parameter optimization, and the development of high-performance titanium alloys. The aim of this work is to provide theoretical guidance and technical support for microstructure optimization and performance enhancement of additively manufactured titanium alloys.

• Heterostructures Titanium Matrix Composites： A Review

  Li Shufeng, Liu Huiying, Li Shaolong, Liu Lei, Zhao Yongqing

  2026,55(4):1115-1128 DOI: 10.12442/j.issn.1002-185X.20250217

  Abstract(32) HTML(57) PDF(16.13 M)( 172)

  Abstract:Titanium matrix composites (TMCs), owing to their high specific strength and high specific modulus, hold great promise for applications in load-bearing aerospace components. However, the strength-ductility trade-off at room temperature significantly restricts their widespread use. The hetero-deformation induced (HDI) hardening effect in heterogeneous structured materials offers a new approach to overcoming the strength-toughness trade-off bottleneck in TMCs. The recent advances in heterogeneous structured titanium and titanium alloys were outlined, then the current research status and compositing strategies of TMCs were summarized and discussed. The failure mechanisms of homogeneous TMCs were elucidated, and the latest developments in configuration and heterostructure design by the pinning effects of reinforcement phases were highlighted. Taking the "hard-in-soft" network structures and "soft-in-hard" granular structures as examples, this work reviewed the design concepts, fabrication methods, classification, and strengthening mechanisms of heterogeneous structured TMCs, providing insights and references for the development of TMCs with a well-balanced strength-ductility relationship.

>Materials Science

• Corrosion Behavior of FeCr_xMnAlCu High-Entropy Alloys in 3.5wt% NaCl Solution

  Feng Li, Zhang Xian, Ma Kai, Zhao Yanchun, Ling Yajun, Liu Ruilong, Fu Xuan

  2026,55(4):877-889 DOI: 10.12442/j.issn.1002-185X.20250060

  Abstract(25) HTML(23) PDF(8.17 M)( 120)

  Abstract:In this study, FeCr?MnAlCu (x=0, 0.5, 1.0, 1.5, 2.0) high-entropy alloys were fabricated using vacuum arc melting, and the corrosion behavior of these alloys in 3.5wt% NaCl solution at room temperature was investigated by electrochemical dynamic potential polarization curves and immersion experiments. The microstructure results show that the high-entropy alloy with x=0 has a body-centered cubic phase structure, whereas the high-entropy alloys with x=0.5–2.0 have a mixed face-centered cubic+body-centered cubic dual-phase structure. The corrosion results show that the corrosion resistance of the high-entropy alloy is increased with the increase in Cr content. Among them, the high-entropy alloy with x=2.0 exhibits the optimal corrosion resistance: the highest self-corrosion potential (E_corr=-0.354 V vs. Ag/AgCl), the smallest self-corrosion current density (I_corr=1.991×10^-6 A·cm^-2), and the smallest corrosion rate (0.0292 mm/a). The composite passivation film of oxides and hydroxides is formed on the surface of the corroded high-entropy alloys, and the Cr₂O₃ content is increased with the increase in Cr content, which effectively improves the stability and protective properties of the passivation film.

• Influence of SiC Content on Foaming Stability, Cell Structure, and Compression Performance of SiC/Al-Based Composite Foam Prepared by Two-Step Foaming Method

  Huang Wenzhan, Liu Tao, Chen Yao, Wang Lucai, Wu Jianguo, You Xiaohong

  2026,55(4):890-898 DOI: 10.12442/j.issn.1002-185X.20250062

  Abstract(20) HTML(21) PDF(4.28 M)( 123)

  Abstract:SiC/Al-based composite foams were prepared by a two-step foaming method. The influence of the SiC content and its distribution uniformity on the foaming stability, cell structure, and mechanical properties of the aluminum foams was investigated. The macro/micro-features of the aluminum foams were characterized and analyzed. Results demonstrate that an appropriate increase in SiC content and the uniform distribution of SiC can improve the foaming stability, optimize the cell diameter and cell wall thickness, ameliorate the cell distribution, and enhance the hardness and compressive strength of the aluminum foams. However, either insufficient or excessive SiC leads to uneven distribution of SiC particles, which is unfavorable to foaming stability and good cell structure formation. With 6wt% SiC, both the foaming stability and cell structure of the aluminum foam reach the optimal state, resulting in the highest compressive strength and optimal energy absorption capacity.

• Effects of Crystal Orientations and Grain Boundaries on Nanoindentation Behavior of γ-TiAl Alloys

  Niu Wenshuai, Li Haiyan, Zeng Linghao, Cao Hui, Chen Wenke, Han Chenyang, Feng Ruicheng, Chen Tao

  2026,55(4):899-913 DOI: 10.12442/j.issn.1002-185X.20250129

  Abstract(25) HTML(22) PDF(4.91 M)( 125)

  Abstract:To elucidate the deformation mechanisms of γ-TiAl, the nanoindentation experiments and crystal plasticity finite element (CPFE) simulation were employed to investigate the effects of crystal orientations and GBs on the mechanical properties of γ-TiAl alloys. A crystal plasticity constitutive model was developed, and load-displacement curves, hardness, and Young's modulus were obtained for both single grains and GBs in γ-TiAl alloys. Based on the aforementioned model, this study investigated the distribution patterns of surface morphology around the indentation sites of individual grain and GBs. It also analyzed the cumulative shear strain distribution, slip system activation, and the interaction between GBs and dislocation slip for various crystal orientations. The results indicate that the mechanical response and pileup behavior exhibit significant anisotropy due to the interplay among the indenter geometry, material slip systems, and cumulative shear strain distribution. Moreover, the interaction between GBs and dislocation slip substantially alters dislocation distribution, thereby influencing material flow and playing a critical role in the mechanical response and plastic deformation of the material.

• Micro-Nanostructured High-Strength and High-Conductivity Cu0.9Cr0.1Zr Alloy Prepared by C-ECAP, Cryogenic Rolling, and Aging

  Guo Tingbiao, Li Yingying, Qian Danchen, Deng Yang, Zhang Guoqing, Wang Yanfeng, Li Wenbing, Ling Dekui

  2026,55(4):914-925 DOI: 10.12442/j.issn.1002-185X.20250223

  Abstract(28) HTML(26) PDF(5.76 M)( 118)

  Abstract:The Cu0.9Cr0.1Zr alloy was deformed through continuous equal channel angular pressing (C-ECAP) through Route A, followed by liquid nitrogen cryogenic rolling (CR) and aging treated at 450 °C. The microstructure, mechanical properties, and conductivity of the alloy were detected by electron back-scattered diffractometer, energy dispersive spectroscope, X-ray diffractometer, scanning electron microscope, and transmission electron microscope. The evolution mechanism of the texture during the deformation process and its influence on mechanical properties were analyzed. The results show that directional shear bands form in the CuCrZr alloy during the C-ECAP process, and the preferred orientation of the microstructure is consistent with the rolling direction. After deformation, the number of precipitated phases (mainly Cr) increases with the prolongation of aging time, accompanied by the appearance of micro-nanostructured fibrous structure in the alloy. After C-ECAP for three passes, 75% CR deformation, and aging at 450 °C for 2 h, the tensile strength, microhardness, and conductivity reach 538 MPa, 168 HV, and 80%IACS, respectively. CR, aging heat treatment, and formation of recrystallization texture are all conducive to the improvement of conductivity.

• Hot Deformation Behavior of New Heat-Resistant Alloy SP2215

  Liang Kai, Yao Zhihao, Fu Yingying, Wang Hongying, Zhang Longyao, Cheng Jian, Dai Weixing, Dong Jianxin

  2026,55(4):1019-1036 DOI: 10.12442/j.issn.1002-185X.20240768

  Abstract(19) HTML(21) PDF(7.87 M)( 111)

  Abstract:A series of hot compression tests were conducted on the new heat-resistant alloy SP2215 for supercritical and ultra-supercritical power plant superheater/reheater tubes using a Gleeble 3500 thermal simulation testing machine at 1100–1250 ℃ and the deformation rate of 0.01–10 s^–1 with a deformation amount of 50%. The influence of deformation temperatures and deformation rates on the rheological curve and deformation structure of the alloy was investigated. Furthermore, by modifying the rheological curve based on friction and temperature effects, we established thermal deformation Arrhenius constitutive model, Avrami dynamic recrystallization model, and Yada dynamic recrystallization average grain size model for SP2215 alloy. Additionally, Prasad-Murty-Malas hot working maps were constructed for alloys based on various rheological instability criteria. The results indicate that as the deformation temperature increases, the degree of work hardening decreases while dynamic recrystallization becomes more obvious in SP2215 alloy. Moreover, higher strain rates result in increased flow stress and work hardening rate for this alloy. The recrystallization of the lowest degree occurs at a strain rate of 1 s^–1; however, without certain conditions, mixed crystal phenomenon may occur easily in this alloy. Under experimental conditions in this research, the optimal thermal deformation window for SP2215 alloy is the temperature of 1200–1250 ℃ and the strain rate of 5–10 s^–1.

• Performance of Diesel Particulate Filter Under Different Catalyst Loadings

  Zhang Yunhua, Xu Yaoxin, Lou Diming, Fang Liang

  2026,55(4):1037-1044 DOI: 10.12442/j.issn.1002-185X.20240778

  Abstract(17) HTML(16) PDF(2.94 M)( 112)

  Abstract:The diesel particulate filter is an effective technology to reduce diesel particulate emissions, and its performance is closely related to catalyst loading. Based on the platform test system of heavy diesel engine, the influence of catalyst amount on the pressure drop, gas state and particulate emission reduction performance of diesel CDPF regeneration was studied. The results show that the exhaust back pressure of catalyst increases linearly with the increase in catalyst loading. When catalyst loading increases from 0 g/ft³ to 5, 10 and 20 g/ft³(1 ft³=0.0283 m³), the average exhaust back pressure increases from 2.94 kPa to 3.44, 3.96 and 4.51 kPa, respectively. The larger the amount of catalyst, the better the emission reduction effect of the catalytic converter on CO and total hydrocarbon (THC). When catalyst loading increases from 0 g/ft³ to 5, 10 and 20 g/ft³, CO emission decreases from 78.94×10^–6 to 71.39×10^–6, 68.12×10^–6 and 63.30×10^–6, and THC emission concentration decreases from 57.34×10^–6 to 48.31×10^–6, 46.93×10^–6 and 44.51×10^–6, respectively. The amount of catalyst has a significant effect on NO oxidation, but not on NO_x emission concentration. Catalyzed diesel particulate filter (CDPF) can achieve a reduction rate of more than 95% for particulate matter and particulate number. Increasing catalyst loading improves the particulate emission reduction effect of CDPF, with a more significant improvement in the reduction effect of nucleation particles. The results of this study have important reference value for the design of high-performance CDPF.

• Hot Deformation Behavior and Microstructure Evolution of a Novel Hot Extruded Nickel-Based Superalloy FGH4113A

  Yang Jinlong, Yin Chao, Xiong Jiangying, Guo Jianzheng, Feng Ganjiang

  2026,55(4):1045-1057 DOI: 10.12442/j.issn.1002-185X.20240790

  Abstract(13) HTML(24) PDF(18.98 M)( 114)

  Abstract:To investigate hot working properties and to control microstructure of the extruded novel nickel-based superalloy FGH4113A, the thermal deformation behavior and microstructure characteristics were studied using Gleeble thermal compressing machine, OM, SEM, and EBSD. Hot deformation experiments were conducted within the temperature of 1050–1150 ℃ and strain rate of 0.001–0.1 s^–1. The results indicate that the grain size of extruded FGH4113A superalloy increases after holding at 1150 ℃. Deformation temperature and strain rate have a significant impact on the deformation flow stress and microstructure evolution. It is recommended for the extruded superalloy to undergo thermal deformation at temperature of 1080–1100 ℃ and strain rate of 0.001–0.01 s^–1 within the γ+γ′ microduplex region. After deformation under these conditions, grains are fully recrystallized and size distribution is uniform, with average size controlled within 5 μm. The residual dislocation density within the grain is small, and the misorientation differences are not significant. Recrystallized grain and deformed original grain can be distinguished from multiple dimensions such as LAM, GOS, and IPF.

• Preparation and Magnetic Properties of Ce_xY_3-xFe₅O₁₂ Polycrystal with High Magneto-Optical Properties

  Luan Lijun, Xu Changyan, Zhang Ziqiao, Xie Haichen

  2026,55(4):1058-1067 DOI: 10.12442/j.issn.1002-185X.20240113

  Abstract(23) HTML(25) PDF(3.48 M)( 121)

  Abstract:The garnet type polycrystal Ce_xY_3-xFe₅O₁₂ doped with Ce³⁺ was prepared by an optimized sol-gel method (x=0, 0.1, 0.2, 0.3; Ce:YIG). Crystals with no derived impurities and high magneto-optical properties prepared by pre-sintering and sintering in a wide temperature range of 900–1400 ℃ were obtained. Thermogravimetric analysis was used to determine the the crystal synthesis temperature of 890 ℃. XRD results show that the crystal lattice constant varies from 1.237 241 nm to 1.241 210 nm, and the impurity phase CeO₂ appears when x>0.2. SEM analysis shows that the grain size of Ce:YIG increases with the increase in sintering temperature and Ce³⁺ content, and its size distribution ranges from 0.257 to 6.52 μm, which is the maximum size of YIG crystal obtained at present. All Ce:YIG samples were ferromagnetic at room temperature, with saturation magnetization varying from 23.47 to 28.10 (A·m²)·kg^–1. The permeability of Ce_0.1Y_2.9Fe₅O₁₂ crystal sintered at 1200–1300 ℃ is as high as 3.68–3.90. According to the relationship between Faraday rotation angle and permeability, the polycrystal sintered in this temperature range is likely to obtain the best Faraday rotation performance.

• High-Temperature Steam Oxidation Behavior of Zr-xSn-0.35Fe-0.15Cr Alloys Under Simulated Loss of Coolant Accident Conditions

  Ma Qingchao, Yao Meiyi, Wang Jinxin, Hu Lijuan, Xu Shitong, Xie Yaoping, Zhou Bangxin

  2026,55(4):1068-1077 DOI: 10.12442/j.issn.1002-185X.20240792

  Abstract(18) HTML(24) PDF(7.44 M)( 112)

  Abstract:Zirconium alloy cladding will undergo high-temperature steam oxidation in a loss of coolant accident to make it be brittle, thereby leading to rupture due to absorbing oxygen, which will affect the safe operation of nuclear reactors. The high-temperature steam oxidation behavior of Zr-xSn-0.35Fe-0.15Cr (x=0.5, 0.75, 1.0, 1.2 and 1.5, wt%) alloys at 800–1200 ℃ was studied by a synchronous thermal analyzer equipped with a steam generator. The cross-sectional microstructures of the samples after high-temperature steam oxidation were observed by OM, and the O content was tested by EPMA. Results show that the high-temperature steam oxidation resistance and oxidation kinetics of zirconium alloys show a certain regularity with Sn content at different temperatures, which is mainly related to the action mechanism of α-Zr? β-Zr and m-ZrO₂?t-ZrO₂ phase transformation behavior of zirconium alloys. As the oxidation temperature increases, the oxidized alloy samples present a double-layer structure of ZrO₂ and α-Zr(O), accompanied by the appearance and disappearance of the mixed layer structure of β-Zr+α-Zr(O), which is caused by the effect of O on the α?β phase transformation. The increase in Sn content inhibits the diffusion of O from α-Zr to β-Zr. From the perspective that the increase in Sn content affects the α-Zr?β-Zr phase transformation and inhibits the diffusion of O from α-Zr to β-Zr, the mechanism of the effect of Sn content on the high-temperature steam oxidation behavior of zirconium alloys at different temperatures was discussed.

>Reviews

• Research Progress of Ta-Nb-Hf-Zr-Ti High Entropy Alloy Superconductors

  Cao Likun, Yang Fang, Hao Qingbin, Zhang Shengnan, Yan Guo, Zhang Pingxiang

  2026,55(4):926-940 DOI: 10.12442/j.issn.1002-185X.20250130

  Abstract(26) HTML(37) PDF(4.48 M)( 128)

  Abstract:High-entropy alloys, a novel class of materials characterized by the statistical distribution of multiple principal elements on simple crystalline lattices, have emerged as a research hotspot in materials science and condensed matter physics due to their exceptional mechanical properties and unique high-entropy characteristic. Since the discovery of the first high-entropy superconductor in 2014, exploring their superconducting performance and advantages has progressively become a frontier in scientific research. The Ta-Nb-Hf-Zr-Ti system, in particular, exhibits remarkable mechanical robustness, outstanding radiation tolerance, and superconducting performance comparable to the binary NbTi alloy, positioning it as a promising candidate for advanced applications, such as high-field superconducting magnets, superconducting electric motors, and next-generation nuclear fusion reactors. This review systematically summarized global research progress on Ta-Nb-Hf-Zr-Ti-based superconductors, aiming to provide a comprehensive reference for advancing this burgeoning field.

Online First

• Research Progress on Room Temperature Discontinuous Yielding Behavior of Metal Materials

  Fan Yurong, Xue Xiangyi, Lai Minjie, Li Jinshan, Luo Ting

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250297

  Abstract(100) PDF(1.26 M)(33)

  Abstract:Discontinuous yielding of metal materials during room temperature deformation is a critical scientific issue that significantly affects their mechanical properties and application safety. This review systematically summarizes recent research advancements in this field, with a focus on the characteristics, influencing factors and underlying mechanisms of discontinuous yielding. The discontinuous yielding phenomenon is mainly characterized by a yield drop and a stress plateau on the stress-strain curve. Studies have shown that microstructural characteristics such as alloy composition, recrystallization degree, grain size and morphology, as well as phase composition and stability, server as primary factors influencing discontinuous yielding. These factors affect the yielding behavior by regulating dislocation movement and deformation mechanisms. Furthermore, this work explores the intrinsic relationship between discontinuous yielding, room temperature deformation mechanism and the work hardening behavior in metallic materials. Based on current research, future studies should focus on the microstructure regulation, alloy design, deformation mechanisms and the development of constitutive models to deepen the understanding of discontinuous yielding and provide a foundation for optimizing material properties.

• Simulation and Control of Forming Defects in Gel Casting of Yttria-Stabilized Ceramic Molds for Titanium Alloy

  LI Shuai, NING Shuai, JI Zhijun, LIU Yan, ZHANG Weitao, DING Xianfei, NAN Hai, HUANG Kuidong, FAN Xueling, LU Zhongliang, LIDichen

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250299

  Abstract(19) PDF(1.30 M)(29)

  Abstract:To address nodular protrusions on titanium-alloy closed impellers caused by gas entrapment during gelcasting of integrated Y?O? (yttria) ceramic molds, this work establishes a predictive and control framework that couples a Carreau non-Newtonian viscosity model with a transient two-phase VOF filling solver. Rheological experiments are fitted to obtain the Carreau parameters for the yttria slurry (relative error < 5%), enabling time–space reconstruction of bubble generation–migration–entrapment throughout filling. The simulated entrapment locations exhibit strong spatial correspondence with computed-tomography (CT) voids in ceramic molds and nodular defects on Ti-alloy castings at both the impeller and bottom regions. Parametric studies indicate that a moderate filling velocity of 0.05 m·s?1 markedly reduces trapped-gas volume; a bottom-fill configuration essentially eliminates entrapment in the impeller region; and, on this basis, applying horizontal vibration (50 Hz, 1 mm) during and after filling removes the remaining bubbles. Ceramic molds fabricated with the optimized parameters were verified by scanning, confirming the disappearance of gas entrapment within the impeller. The study provides a reusable framework for defect prediction and active process control in gelcasting of complex Ti-alloy components.

• Overview of Laser-Based Repair and Directed Energy Deposition of Nickel-Based Superalloys

  Qingzheng Wang, Junfeng Xiao, Xin Lin, Wenshu Tang, Song Gao, Quanming Liu, Haozhi Chai

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250302

  Abstract(17) PDF(1.45 M)(27)

  Abstract:Nickel-based superalloys are widely used in critical hot-section components of high-end equipment such as aero-engines and gas turbines due to their excellent mechanical properties and oxidation resistance at elevated temperatures. As an advanced manufacturing method, laser directed energy deposition (L-DED) has demonstrated great potential in the repair of complex components, owing to its advantages such as mold-free near-net shaping, controllable energy input, small heat-affected zone, and dense microstructure in the deposited layer. However, during the L-DED repair process, nickel-based superalloys undergo complex rapid melting and solidification as well as repeated thermal cycling, resulting in unique microstructural features and a high tendency to develop typical metallurgical defects such as pores, cracks, stray grains, and microstructure degradation, which can significantly degrade their mechanical performance. This paper systematically reviews the typical defects and their control methods, microstructural evolution characteristics, and compares the key mechanical properties, including room-temperature tensile strength, high-temperature creep resistance, and fatigue performance, between directly deposited and repaired nickel-based superalloys. Furthermore, based on existing theoretical models, the mechanisms of defect formation and microstructural evolution are analyzed, highlighting the current technical challenges and limitations in this field. This review provides a theoretical foundation and direction for the process optimization, microstructural control, and performance enhancement of laser-repaired or -formed nickel-based superalloys.

• Electrically-induced dynamic globularization behavior and related kinetics model of TA15 alloy with initial lamellar structure

  Yan Siliang, Liu Zilong, Li Junhui, Meng Miao, Huang Liang

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250314

  Abstract(77) PDF(1.23 M)(29)

  Abstract:The dynamic globularization rules, underlying mechanisms and globularization kinetics model of TA15 alloy with initial lamellar structure were studied by pulsed electric current assisted compression tests and quantitative analysis of metallographic structure. The results indicate that the increased current density further promotes the flow softening phenomenon. The globularization rate increases with the increase of current density and pre-deformation. Based on the Avrami equation, a kinetics model of electrically-induced dynamic globularization for TA15 alloy is established. The model predicts that the ranges of the critical strain εc for dynamic globularization and the strain εf for completing dynamic globularization are between 0.090 - 0.187 and 5.02 - 6.31, respectively. And these two critical strains both decrease with the increase of current density. The globularization kinetics rate first increases and then decreases with the increase of pre-strain and current density. In addition, the higher the current density, the greater the peak globularization kinetics rate and the smaller the critical strain for this peak value.

• The Effect of Surface Nanogradient on the Microstructure and Properties of hot-rolled Ti-6.5Al-2Zr-1Mo-1V Alloy

  Available online:February 13, 2026  DOI:

  Abstract(26) PDF(2.15 M)(23)

  Abstract:To address the failure caused by surface corrosion fatigue of titanium alloy structural components and to extend the service life of titanium alloys used in aircraft structures, Supersonic fine particle bombardment (SFPB) technology was applied to the hot-rolled Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy with varying impact times. This process created a gradient nanostructure on the surface of the samples, and various instruments and equipment were used to study the effects on the microstructure, microscopic morphology, and mechanical properties after different treatment times. At an SFPB treatment time of 60 s, the surface average nanocrystal grain size of the hot-rolled structure was minimized, measuring 30.4 nm. The surface roughness of the treated samples increased compared to the original ones, with the minimum surface roughness occurring at 60 s. However, longer impact times led to the formation of microcracks on the sample surface. The SFPB treatment introduced high compressive residual stress on the sample surface, resulting in a significant increase in microhardness. After the SFPB treatment, the sample"s strength increased, with a slight decrease in elongation before stabilizing. At a treatment time of 60 s, the best combination of strength and plasticity was achieved. The corrosion fatigue life of the SFPB-treated samples was improved by 12.7 times compared to the untreated samples. The SFPB treatment was able to generate a gradient nanolayer near the surface of the TA15 titanium alloy, significantly enhancing its tensile properties and corrosion fatigue life.

• Compressive properties and deformation behavior of bionic honeycomb nested lattice structures formed by laser selective melting

  Liu Zheng, Zha Zhengshu, Peng Cong, Zhang Wenwei, Chen Meng, Luo Le, Zhang Qi

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250336

  Abstract(24) PDF(1.64 M)(27)

  Abstract:Honeycomb structures are widely used in lightweight material design due to their characteristics of being lightweight, high strength, and energy-absorbing. However, conventional honeycomb structures have poor lateral performance and structural stability. To address these issues, this study nests three types of truss rod unit lattice structures within the honeycomb cavities to obtain a new honeycomb nested lattice structure. Using AlSi10Mg powder as the material, the selective laser melting (SLM) technique was employed to fabricate samples with different relative densities, including the new BCC honeycomb nested lattice structure (HC-N-BCC), honeycomb nested symmetric rod lattice structure (HC-SP), new fluorite-type honeycomb nested lattice structure (HC-N-F), and hollow honeycomb structure (HC-E). These samples were then tested for lateral compression mechanical properties, macro- and micro-scale deformation mechanisms, and energy absorption. The results show that the lateral compression performance of the honeycomb nested lattice structures is significantly superior to that of the hollow honeycomb structure. At 46% relative density, the HC-SP structure exhibits a compression modulus and peak stress that are 43% and 44.7% higher than those of HC-E, respectively, and at 50% strain, its energy absorption (EA) and crushing force efficiency (CFE) are 7.7 and 5.3 times higher than those of HC-E. When truss unit lattices are embedded in the honeycomb cavities, the honeycomb shell deforms gradually and uniformly instead of fracturing instantly, greatly improving the compressive stability of the honeycomb structure. Furthermore, the larger the proportion of the truss volume in the overall structure, the greater the performance improvement of the honeycomb nested lattice structure.

• Microstructural Evolution and Mechanical Properties of Heat-Treated MoNbVTa Refractory High Entropy Alloys

  Guo Wei, Zhu Mengyuan, Zheng Weijie, Zhao Shiyang, Zhao Mi, Wu Shusen

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250333

  Abstract(22) PDF(1.05 M)(24)

  Abstract:The present study systematically investigated the microstructural evolution and mechanical properties of MoNbVTa?.5 refractory high-entropy alloys (RHEAs) under varying annealing temperatures and holding times. It reveals that microstructural homogenization improves with increasing annealing temperature at a fixed 24 h of holding time. However, annealing above 1500 °C induces the precipitation of (Nb,Ta)-rich phases, which deteriorates ductility. At 1400 °C, prolonged holding time enhances yield strength, while plastic strain initially increases and then decreases due to the pinning effect of precipitated phases. Notably, homogenization annealing at 1300 °C for 24 h achieves a synergistic improvement in strength and plasticity: the yield strength increases to 1530 MPa, and plastic deformation reaches 9.2%, representing a 58.6% enhancement compared to the as-cast state.

• Research Progress on Wear Resistance of Laser Welded WC-Co Coatings

  Qu Kepeng, Zhao Mingyue, Wang Nan, Zhai Qixun, Chen Yongnan, Zhao Yongqing

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250348

  Abstract(51) PDF(1.52 M)(43)

  Abstract:Laser cladding is widely employed for surface strengthening of titanium alloys and other metals owing to its advantageous metallurgical bonding and narrow heat-affected zones. Among various strengthening materials, WC is utilized as a superhard ceramic phase. Through its synergistic effect with Co, the hardness and wear resistance of the clad layer can be effectively enhanced. However, research has demonstrated that laser power exerts a significant influence on clad layer quality. When excessive power is applied, excessive dissolution of WC particles occurs, facilitating crack initiation and pore formation. Conversely, insufficient power commonly leads to defects such as unmelted particles and porosity.This review focuses on the influence of laser power on WC grain size and growth mechanisms within the coating, summarizing the coating"s wear resistance mechanisms. Furthermore, the main limitations currently encountered in the preparation of WC-Co coatings are analyzed, along with corresponding improvement strategies. Finally, existing challenges and future development trends are discussed.

• The Effect ofY2O3 Content on the Microstructure and Properties of Stellite 6 +Y2O3 Laser Cladding Layers on the Surface of 17-4PH Steel

  Shang Xiaofeng, Zhu Qingyong, Jia Ye, He Chen, Zhao Yuhui, Zhao Jibin

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250356

  Abstract(49) PDF(1.79 M)(24)

  Abstract:In this study, wear-resistant and corrosion-resistant cobalt-based Stellite 6 alloys were prepared by varying the Y2O3 content (0, 0.3, 0.6, and 0.9 wt%). The effects of Y2O3 addition on the microstructure, microhardness, wear resistance, and corrosion resistance of the laser-cladded Stellite 6 samples were investigated. The results indicate that the addition of Y2O3changes the grain structure from coarse columnar grains to fine, uniform equiaxed grains. The sample with 0.6 wt%of Y2O3exhibits an average grain size of 160.8 μm, representing a maximum grain refinement of 66.3% compared to the sample without of Y2O3 addition.Furthermore,of Y2O3particles are mainly dispersed in the interdendritic regions of the Stellite 6 alloy samples, forming a particle layer in front of the dendrite grains, which inhibits grain movement and solute atom diffusion.The sample with 0.6 wt% of Y2O3addition shows the highest microhardness, with an average value of 532 HV0.2. Due to the smallest grain size and spacing between of Y2O3 particles, it also demonstrates the best wear and corrosion resistance performance. Compared to the sample without of Y2O3addition, the maximum microhardness increases by 22.6%, the wear rate decreases by up to 72.2%, the corrosion potential increases by up to 25.6%, and the corrosion current density decreases by up to 39.8%.

• Dynamic tensile deformation mechanisms of Fe40Mn20Cr20Ni20 high-entropy alloys at cryogenic temperatures

  Qiao Junwei, Wang Zeming, Zhang Yong, Peter K. Liaw

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250358

  Abstract(24) PDF(2.91 M)(26)

  Abstract:As an emerging structural material, high-entropy alloys (HEAs) have significant application potential in high-strain-rate environments and across a range of temperatures, including both high and low temperatures. Previous studies mainly focused on the mechanical behavior of HEAs under high-speed loading or low temperature, which is limited to a single extreme environment. This paper primarily discusses the mechanical behavior and microscopic mechanism of the Fe40Mn20Cr20Ni20 high-entropy alloy (HEA) at high and low temperatures and high strain rates (Split Hopkinson bar) and utilizes relevant theoretical models to fit the yield strength and flow stress of the HEA. The tensile test results show that the HEA exhibits excellent strength-plastic synergy and excellent work-hardening ability under the condition of reducing temperature or increasing strain rates. During the dynamic tensile process, the interaction of different forms of dislocations and deformation twins together improves the strength and work-hardening ability of the HEA. The Zerilli-Armstrong (Z-A) constitutive model was used to predict the temperature sensitivity and strain-rate sensitivity of the yield strength of the HEA. At the same time, the Taylor model was used to predict the change of the HEA flow stress with the strain rate under dynamic tension, and the model was applied to low-temperature dynamics. The fitting results were consistent with the experimental results, which provided a theoretical basis for the subsequent prediction of HEAs strengths.

• Research on the Segmentation Algorithm for GH4169 Alloy Grains Based on a Joint Attention Mechanism

  Deng Bowen, Li Ke, Zhang Xinyuan, Zhao Yanru, Shi Puying, Wang Hu, Gao Huixian, Yang Chao

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250360

  Abstract(30) PDF(1.73 M)(23)

  Abstract:To tackle the segmentation challenges arising from the complex morphology, significant size variations, blurred boundaries, and tight interconnections of superalloy grains, this paper presents a grain segmentation network integrated with a joint suppression attention mechanism that fuses channel and spatial information. The network combines the global modeling capacity of Swin Transformer and the local detail restoration capability of CNN, and embeds the aforementioned joint suppression attention mechanism, which integrates channel and spatial information, into the decoder. This mechanism effectively suppresses noise and texture interference, enhances the abilities of feature screening and generalization, and reinforces the fusion of shallow and deep features, thereby markedly improving the continuity of grain boundaries. Experimental results demonstrate that the proposed algorithm achieves 67.34% and 78.62% in terms of IoU and F1-score, respectively, on the self-constructed metallographic dataset, with all metrics outperforming those of mainstream grain segmentation algorithms for superalloys.

• Study of the Crystallization Morphology of Ti-1023 Alloy Ingot

  Wang Yangyang, Liu Xianghong, Wang Qing, Wu Jiangtao, Xia Yong, Zhao Xiaohua, Fu Jie

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250361

  Abstract(20) PDF(1.22 M)(33)

  Abstract:In this paper, a numerical model was established using the finite volume method to establish a corresponding relationship between the simulated temperature and flow fields and the actual solidification structure of the ingot. The grain growth direction and grain morphology transformation of the industrial-scale Ti-1023 alloy ingot were investigated. The results indicated that the predicted grain growth direction (angle) of columnar grain at the bottom and edges of the ingot coincides with the actual by more than 90% through temperature gradient components and ; The G-R (temperature gradient-solidification rate) diagram was plotted. There is an obvious boundary between equiaxed and columnar grains, and the critical parameters G* for columnar-equiaxed crystal transformation varies under different melting processes.

• Study on Degradation Mechanisms and Rejuvenation Processes for Microstructure and Properties of Gas Turbine Blades

  Sun Haohua, Zhang Jianting, Cui Jinyan, Xiao Lei, Guo Jianzheng

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250376

  Abstract(55) PDF(1.65 M)(38)

  Abstract:The degradation behavior of the microstructure and mechanical properties of a long time serviced GTD111 DS superalloy turbine blade was investigated. Rejuvenation heat treatment was subsequently applied by using a treatment of hot isostatic pressing (HIP) followed by solution and double-aging treatments. The results demonstrated that during service: pore density increased significantly from blade tip to root; MC carbides degenerated into M??C? carbides and η phase; secondary γ′ precipitates underwent severe spheroidization and rafting, accompanied by the dissolution of tertiary γ′ precipitates. The overall microstructural degradation pattern along the blade longitudinal axis follows the order: tip > central region > root > tenon, and along the transverse axis follows the order: trailing edge > leading edge > suction side > pressure side. The microstructure degradation directly led to a progressive reduction in Ultimate tensile strength at both room temperature and 980 °C and stress rupture life at 980 °C/220 MPa from the tenon to the blade tip. After rejuvenation heat treatment, the microstructure and mechanical properties were markedly improved: the area fraction of microporosity at the blade tip was reduced, MC carbides were partially restored, and the sizes of secondary and tertiary γ′ precipitates decreased to approximately 0.5 μm and 59 nm, respectively. Ultimate tensile strength of the blade tip increased from 810 MPa to 1122 MPa at room temperature and from 388 MPa to 468 MPa at 980 °C; and the stress rupture life (980 °C/220 MPa) increased from 1.95 h to 11.31 h. After rejuvenation, all mechanical properties at the blade tip exceeded those of the tenon region.

• The influence of rare earth Y on the high-temperature oxidation behavior of Mn-containing β-solidified γ-TiAl alloys

  Zuo Huichao, Hao Junjie, Xue Peng, Chen Bo, Wang Jianjun, Li Xiaobing, Liu Kui

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250377

  Abstract(54) PDF(1.00 M)(28)

  Abstract:This study investigates the influence of trace amounts of rare earth element Y on the high-temperature oxidation resistance of a low-cost and easily deformable TMMW (Ti44Al3Mn-0.8(W,Mo)-(B,C)) alloy at 800°C. The microstructure and oxide scale formation of the alloy were systematically analyzed using EPMA, XRD, and TEM techniques, and the underlying mechanisms by which Y affects the oxidation resistance were explored in detail. Experimental results indicate that the addition of trace Y exerts a notable effect on the alloy"s microstructure. After identical heat treatment, the Y-free alloy primarily consists of γ, α₂, and β_o phases, whereas the Y-containing alloy not only retains these phases but also exhibits precipitation of the YAl₂ phase at lamellar boundaries and within the matrix, with minimal formation of Y₂O₃. Cyclic oxidation kinetics tests reveal that the oxide scale formed on both alloys comprises a three-layer composite structure: TiO₂/Al₂O₃/TiO₂ + Al₂O₃, with the transition layer mainly composed of TiMn₂-Laves phase and a small quantity of Mo- and W-rich β_o phase. The addition of 0.3 at.% Y effectively reduces oxidation weight gain, enhances spallation resistance of the oxide scale, and significantly decreases the βo phase content in the transition layer.

• Effects of Co and C on the Microstructure and Aging Stability of a New Type of Hot-Corrosion-Resistant Nickel-Based Single-Crystal Superalloy

  Wang Jiayu, Liu Enze, Tan Zheng, Tong Jian, Liu Weihua, Li Haiying, Xin xin, Jia Dan, Liu Yichuan, Tu Ganfeng, Xiao Faxin, Sun Shuchen, Mao Chengrong, Ning Likui

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250379

  Abstract(43) PDF(1.67 M)(45)

  Abstract:This study investigates the effects of Co and C on the microstructural characteristics and the stability during long-term aging at 1000°C in a novel hot-corrosion resistant Ni-based single-crystal superalloy. Four single-crystal alloys with varying Co and C contents were prepared via directional solidification and characterized by SEM, EDS, EPMA, and TEM. The results show that C suppresses solidification micropores and reduces γ/γ′ eutectic fraction by promoting the precipitation of MC-type carbides, such as TaC. Co enhances the solid solubility of the γ-matrix, effectively inhibiting the segregation of Re, W, Ta, and Al, although carbides reduce the homogenization efficiency. Co lowers the γ′ solvus temperature and refines the size of γ′ precipitates, while C increases the solvus temperature and promotes γ′ coarsening due to the release of γ′-forming elements during carbide dissolution. During long-term aging, γ′ coarsening follows Lifshitz-Slyozov-Wagner (LSW) kinetics. Both Co and C reduce the absolute value of the γ/γ′ lattice misfit (|δ|) and increase the effective diffusion coefficient (Deff). Co reduces the γ′ coarsening rates, while C accelerates it. The misfit (|δ|) dominates coarsening at fixed C content, whereas Deff governs it at fixed Co content. Predictions from three models for topologically close-packed (TCP) phase precipitation show discrepancies with experimental data: Co promotes TCP formation, while C inhibits it through sequestration of Mo and W in primary MC carbides.

• Research Progress on the Anti-cavitation and Erosion Performance of Laser Cladding Alloy Coatings

  Zhang Zhe, Zhang Shuyan, Wang Tuo

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250384

  Abstract(21) PDF(756.88 K)(32)

  Abstract:Hydraulic machinery serves as the core equipment in hydropower stations and pumping stations, primarily encompassing turbines and pumps. Cavitation and erosion occurring on turbines stand out as the main causes of failure in flow-passing components, and they have remained a critical challenge hindering the development of hydraulic machinery for over six decades. Numerous researchers have consistently found that applying a dense coating on the surface of the base material can effectively mitigate the damage to hydraulic machinery caused by cavitation and erosion. As an advanced surface modification technology, laser cladding has opened up new avenues for the industrial application of such coatings. By summarizing existing studies, this paper comprehensively analyzes the mechanism, influencing factors, and prediction methods of cavitation and erosion. It specifically examines the impact of factors like powder composition and operating conditions on the cavitation and erosion resistance of laser-cladded alloy coatings. Based on the above analysis, the paper addresses the current drawbacks of materials in terms of cavitation and erosion resistance, summarizes the existing problems to date, and outlines the future development directions and trends of laser-cladded alloy coating materials. This work aims to provide valuable references for the development of high-performance laser-cladded coating materials.

• Machine Learning-Assisted Design of Interpretable Models for TiZr-Based High-Entropy Alloys Used in Armor-Piercing Applications

  Luo Hao, Liu Tianyu, Wei Huanan, Gao Xingyong, Fan Feigao, Zhai Anqi, Liu Zhuo

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250385

  Abstract(36) PDF(1.18 M)(33)

  Abstract:Modern military technology demands continuous improvement in the damage efficiency of armor-piercing projectile core materials, driving innovation in high-performance alloy systems. TiZr-based refractory high-entropy alloys (RHEAs, Refractory High-Entropy Alloys), known for their high hardness, compressive strength, and thermal phase stability, have garnered attention due to their potential application in armor-piercing warheads. This study introduces a machine learning (ML)-assisted approach to alloy design, aiming to uncover the complex relationship between composition and performance while improving design efficiency. To address the critical requirement for hardness in armor-piercing applications, a 15-dimensional feature dataset was constructed, incorporating component molar fractions and five key descriptors, based on 157 experimental hardness data points. Eight ML models—including random forest, K-nearest neighbors, and support vector machines—were trained, and XGBoost was identified as the most accurate through hyperparameter tuning via grid search and cross-validation. The SHAP (SHAP，Shapley Additive Explanations) framework was applied to interpret feature contributions. Results indicate that the XGBoost model achieves the highest predictive performance (R2 = 0.73, and the average absolute percentage error is 14.0%). The most influential factors affecting alloy hardness are mixing enthalpy (ΔH_mix), niobium (Nb) content, and atomic size mismatch (δ). Effective hardness control necessitates the synergistic regulation of thermodynamic stability, electronic structure, and geometric dimensions, where inter-feature compensation plays a critical role in optimizing overall performance. This work establishes a novel compositional design paradigm for TiZr-based RHEAs, demonstrating the engineering value of ML in enhancing material development for high-efficiency damage applications.

• Ming-song Hao_{^{1, 2}}, Lin Zhou_², Guan Wang_², Kai Wang_^1*, Jing-jing Liang_^2,3, Jin-guo Li_^2,3*

  Haomingsong, Zhoulin, wangguan, Wangkai, Liangjingjing, Lijinguo

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250386

  Abstract(36) PDF(2.77 M)(35)

  Abstract:Laser additive manufacturing, as an advanced digital forming technology, is widely used in the research of high temperature alloy preparation.GH3536, as a solid solution strengthened nickel-based high temperature alloy, is suitable for the preparation of components for combustion chambers of aero-engines due to its excellent mechanical properties. The control of metallurgical defects, microstructure modulation and mechanical property strengthening mechanism of laser additive manufacturing of GH3536 alloy are reviewed. The current research status and progress of laser additive manufacturing of GH3536 alloy are analyzed, and the research on the influence mechanism of its tensile and creep properties and other research is expected. It is hoped to provide reference for the research and development of laser additive manufacturing of GH3536 alloy.

• The influence of thermomechanical processing on the microstructure and mechanical properties of NiCo-based superalloys

  Gao Ming, Zhang Qian, Qiao Junwei, Gan Bin

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250402

  Abstract(19) PDF(2.18 M)(32)

  Abstract:Achieving an optimal strength-ductility synergy efficiently is a critical objective for advanced structural materials. This study developed a novel grain structure in a NiCo-based superalloy, consisting of residual deformed grains, fine recrystallized grains, and multi-scale L12-γ′ precipitates, using a short-term annealing and aging treatment. Compared to the conventional heat-treated condition (yield strength: 1,106 MPa; elongation: 18.8%), the alloy with a partially recrystallized microstructure exhibited a significantly higher yield strength of 1,371 MPa, while maintaining a ductility of 13.3%. This high strength is attributed to synergistic effects from dislocation strengthening (induced by prior cold rolling), fine grain strengthening, and precipitation reinforcement by γ′ phases. In contrast, the fully recrystallized variant demonstrated a yield strength of 1,390 MPa with an elongation of 14.3%, primarily due to a uniform fine-grained structure and homogeneous γ′ precipitation. The underlying deformation mechanisms were thoroughly investigated, re-vealing that dislocation activity, nano-twins, and L-C locks, in addition to the precipitates, are critical for the outstanding mechanical properties. This work provides a practical and cost-effective processing strategy for developing high-performance NiCo-based superalloys for demanding engineering applications.

• Dong Chengli1,2, Hong Jianfeng1,2, Sha Aixue1,2, Peng Zichao2, Wang Xuqing2, Li Xingwu1,2

  Dong chengli, Hong Jianfeng, Sha Aixue, Peng Zichao, Wang Xuqing, Li Xingwu

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250405

  Abstract(25) PDF(1.04 M)(30)

  Abstract:In view of the lack of key issues on the service performance evaluation of the extruded and forged FGH95 alloy under the service conditions of the aero-engine powder disc components, the present study first designed a feature-base specimen based on the maximum principal strain gradient on the retaining groove of the powder disc component according to certain design criteria, and verified the design method. Then, the fatigue life method based on the Theory of Critical Distances (TCD) was employed to predict the service life. Finally, the fatigue life method and failure mechanisms were validated. The results show that the three - dimensional spatial domain automatic search method proposed in the present study can obtain the maximum principal strain gradient on the retaining groove. Compared with the Morrow - modified total strain life method commonly used in engineering, the TCD-base life method considering the strain gradient can more accurately predict the fatigue life of the retaining groove. The important reason why the notched standard round bar specimen cannot accurately predict the fatigue life of the retaining groove is reasonably explained. The differences in the fatigue failure mechanisms of the notched standard round bar specimen, retaining groove and its feature-base specimen are verified by fracture analysis techniques.

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