2025,Volume 54, Issue 7

>2025 Nuclear Materials

• Mechanical Constitutive Model for Equivalent Solid of Fission Gas Bubbles in Irradiated U-10Mo Fuels

  Li Yong, Yan Feng, Zhang Jing, Zang Liye, Ding Shurong

  2025,54(7):1653-1660 DOI: 10.12442/j.issn.1002-185X.20240640

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  Abstract:The internal pressure within fission gas bubbles (FGBs) in irradiated nuclear fuels drives mechanical interactions with the surrounding fuel skeleton. To investigate the micromechanical stress fields in irradiated nuclear fuels containing pressurized FGBs, a mechanical constitutive model for the equivalent solid of FGBs was developed and validated. This model was based on the modified Van der Waals equation, incorporating the effects of surface tension. Using this model, the micromechanical fields in irradiated U-10Mo fuels with randomly distributed FGBs were calculated during uniaxial tensile testing via the finite element (FE) method. The macroscopic elastic constants of the irradiated U-10Mo fuels were then derived using homogenization theory, and the influences of bubble pressure, bubble size, and porosity on these constants were examined. Results show that adjacent FGBs exhibit mechanical interactions, which leads to distinct stress concentrations in the surrounding fuel skeleton. The macroscopic elastic constants of irradiated U-10Mo fuels decrease with increasing the macroscopic porosity, which can be quantitatively described by the Mori-Tanaka model. In contrast, bubble pressure and size have negligible effects on these constants.

• Microstructure and Properties of ZrC Nanoparticles- Strengthened WNiFe Alloys

  Yang Run, Wang Hui, Liu Rui, Wu Xuebang, Wang Xianping, Fang Qianfeng, Liu Changsong

  2025,54(7):1661-1670 DOI: 10.12442/j.issn.1002-185X.20240635

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  Abstract:93W-4.9Ni-2.1Fe alloys strengthened by nanoscale ZrC particles were prepared by spark-plasma-sintering (SPS) and hot rotary swaging, separately. Results show that the addition of a small number of ZrC nanoparticles can refine grains and increase the hardness of the WNiFe alloys, but hinder the formation of the γ-(Ni, Fe) phase during SPS. SPSed WNiFe and WNiFe-ZrC alloys are brittle at room temperature, while the swaged WNiFe and WNiFe-0.5ZrC (wt%) alloys are ductile. At 400 °C, the swaged WNiFe-0.5ZrC alloy exhibits both higher tensile strength and better ductility than the swaged WNiFe. The nanoscale particles distributed in the W grains and γ-(Ni, Fe) phase provide a good pinning effect, which enhances the strength. The thermal conductivity of swaged WNiFe-0.5ZrC is only 71 W·m^-1·K^-1 at room temperature, but it increases to about 100 W·m^-1·K^-1 at 800 °C, which is close to that of pure W (121 W·m^-1·K^-1). These results show the potential of WNiFe alloys as plasma-facing materials in fusion reactor.

• Hot Deformation Behavior and Processing Map of Zr-Sn-Nb-Fe-Cr Alloy

  Li Yuli, Li Hao, Chen Qiuyu, Zhou Xuan, Ma Tianyang, Sun Taotao

  2025,54(7):1671-1677 DOI: 10.12442/j.issn.1002-185X.20240519

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  Abstract:The hot deformation characteristics of induction quenched Zr-Sn-Nb-Fe-Cr alloy forged rod in the temperature range of 600–900 °C and strain rate range of 0.001–1 s^-1 were studied by Gleeble3800 uniaxial hot compression experiment. The results show that the flow stress decreases with the decrease in strain rate and the increase in deformation temperature in the true stress-true strain curve of Zr-Sn-Nb-Fe-Cr alloy forged rod. Moreover, the hot deformation characteristics of the material can be described by the hyperbolic sine constitutive equation. Under the experimental conditions, the average thermal activation energy (Q) of the alloy was 412.9105 kJ/mol. The microstructure analysis of the processing map and the sample after hot compression shows that the optimum hot working parameters of the alloy are 795–900 °C, 0.001–0.0068 s^-1, at the deformation temperature of 600–900 °C, and the strain rate of 0.001–1 s^-1.

• Effect of Ar⁺ Irradiation on the Microstructure and Corrosion Resistance of Zr-4 Alloy

  Xi Jintao, Xin Yong, Zhou Mingyang, Xu Shitong, Hu Lijuan, Xie Yaoping, Li Zhikang, Yao Meiyi, Zhou Bangxin

  2025,54(7):1741-1754 DOI: 10.12442/j.issn.1002-185X.20240771

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  Abstract:Zirconium alloys used as nuclear fuel cladding materials are subjected to neutron irradiation inside the reactor, which affects their corrosion resistance. Ion irradiation can be used to simulate neutron irradiation to study the effect of irradiation on corrosion behavior. In this study, the Zr-4 plate was irradiated with Ar⁺ at 360 ℃ with an electrostatic accelerator. The unirradiated and 5 dpa irradiated samples were corroded in 360 ℃/18.6 MPa/3.5 μL/L Li+1000 μL/L B aqueous solution and 400 ℃/10.3 MPa super-heated steam for 300 d. The microstructure of the samples was characterized by SEM and TEM. Results show that the Zr(Fe,Cr)₂ second-phase particles in the unirradiated samples have hexagonal close-packed structures, whose Fe/Cr atomic ratio is in the range of 1.8–2.0, and the second-phase particles are amorphized after irradiation. Under the two corrosion conditions, during the corrosion process of the irradiated damage zone in the alloy matrix, the oxide film thickness of the irradiated samples is smaller than that of the unirradiated samples, indicating that Ar⁺ irradiation can enhance the corrosion resistance of Zr-4 to a certain extent. However, once the irradiated damage zone is fully oxidized, as corrosion proceeds, the oxide film thickness of the irradiated samples becomes greater than that of the unirradiated samples, suggesting that the oxide film formed in the irradiated damage zone facilitates the diffusion of oxidative ions, accelerating the corrosion of Zr-4. The influence of irradiation on the corrosion resistance of Zr-4 at different stages is discussed from the perspectives of microstructure evolution and stress accumulation in the oxide film induced by irradiation-induced defects.

• Effect of Ar⁺ Irradiation on Microstructure and Corrosion Resistance of Zr-Sn-Nb Alloy

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

  2025,54(7):1755-1767 DOI: 10.12442/j.issn.1002-185X.20240737

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

• Transient High Heat Load Resistance Performance of Rolled Chemical Vapor Deposition Tungsten

  Zhao Tianyu, Wen Pan, Feng Fan, Wang Jianbao, Lian Youyun, Liu Xiang, Tan Chengwen, Tang Jun, Du Juan

  2025,54(7):1768-1776 DOI: 10.12442/j.issn.1002-185X.20240715

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  Abstract:The high heat load in nuclear fusion reactors constantly threatens the service safety of plasma-facing materials. Developing new tungsten materials resistant to transient thermal shock is crucial for advancing the application of fusion energy. This study breaks through the traditional commercial tungsten material preparation process of powder metallurgy billet and hot processing, and proposes an innovative process: first, billets are prepared via chemical vapor deposition (CVD), and then cross rolling is carried out. This process aims to prepare tungsten materials with superior performance. The microstructure, thermal conductivity, mechanical properties, and electron beam thermal shock of new and traditional tungsten materials with different rolling deformation rates were tested. The results indicate that tungsten with a low rolling deformation rate has <100>∥ND texture and exhibits high thermal conductivity. At the same time, the proportion of small angle grain boundaries between the grains of the material is as high as 78.8%, which lead to good comprehensive mechanical properties in the high temperature zone. Good thermal conductivity and mechanical properties result in a transient thermal shock cracking threshold of 0.44–0.55 GW/m², significantly exceeding that of traditional materials.

• Modeling of Fission Gas Irradiation Swelling for UO₂ Fuel in Pressurized Water Reactor Based on Rate Theory

  Zhou Yi, Liu Zhenhai, Xiao Zhong, Liu Shichao, Wang Haoyu, Xin Yong, Sun Dan, Zeng Wei, Yu Junchong

  2025,54(7):1777-1784 DOI: 10.12442/j.issn.1002-185X.20240711

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  Abstract:The irradiation swelling caused by fission gas can promote UO₂ fuel-cladding contact and reduce fuel thermal conductivity, which is a key behavior affecting fuel element performance. A fission gas irradiation swelling model for different burn-up ranges was established based on rate theory. The model first proposed control equations for intragranular gas, intergranular gas, and point defects under low burn-up. Then the control equations for intragranular gas considering grain subdivision and non-equilibrium growth of grain boundary pores under high burn-up were given. Finally, a model for coalescence and coarsening of grain boundary pores was established. On this basis, COMSOL software was used to solve the control equations. The model was preliminarily validated by experimental data. Results show that the predicted bubble size and porosity are in good agreement with the experimental results.

• Effect of Si Content on Microstructure and Mechanical Properties of Niobium-Stabilized Austenitic Stainless Steel

  Liu Yongtao, Chen Shenghu, Jiang Haichang, Rong Lijian

  2025,54(7):1785-1795 DOI: 10.12442/j.issn.1002-185X.20240642

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  Abstract:The microstructure, tensile properties, and impact toughness of niobium-stabilized austenitic stainless steel with Si content of 0.076wt%–3.80wt% were characterized by OM, SEM, and TEM. The results show that variations in Si content exert minimal influence on grain size and primary NbC, and the formation of δ-ferrite is promoted as the Si content reaches 3.80wt%. The planar slip of dislocation is the dominant deformation mechanism of the three steels, and deformation-induced martensitic transformation is induced by the high local plastic strain in the slip band. The increase in Si content promotes the planar slip of dislocation, and the local plastic strain in the slip band is decreased, resulting in the suppression of the deformation-induced martensitic transformation. As a consequence, the transformation from massive martensite to fine lath martensite is promoted with the increase in Si content. The enhancement effect of Si addition on the tensile strength is due to the secondary strain hardening, which is caused by dislocation plane slip and deformation induced martensitic transformation. However, the increased probability of secondary crack formation at the NbC/austenite interface leads to the decrease in elongation. The increase in Si content reduces impact toughness. The decrease in slip band spacing can increase the nucleation sites of void, resulting in a decrease in crack initiation energy. At the same time, the increase in the number of martensite/austenite interfaces leads to a decrease in crack propagation energy.

• Interaction of Dislocations and Helium-Induced Defects in Ti-5331 Alloy

  Zhou Mei, Shi Yunmei, Wu Zhen, Yu Yao, Wang Qianqian, Zhu Te, Wan Mingpan, Cao Xingzhong, Chen Yu, Ma Rui

  2025,54(7):1796-1801 DOI: 10.12442/j.issn.1002-185X.20240641

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  Abstract:The interaction between dislocations and helium-induced defects in Ti-5331 alloy with different cold rolling deformations (0%, 10%, 25%), and the retention behavior of helium in the alloy were investigated by positron annihilation spectroscopy (PAS), transmission electron microscopy (TEM), and grazing incidence X-ray diffraction (GIXRD). The results show that the dislocations generated by deformation in Ti-5331 alloy hinder the diffusion of injected helium atoms into the alloy. Moreover, a large number of vacancy defects generated by irradiation in the alloy form helium vacancy complexes with helium atoms, which finally evolve into helium bubbles. The irradiation damage of the inner layer of Ti-5331 alloy after deformation is lower than that of the surface layer. Additionally, the helium desorption amounts of the alloy with deformations of 0%, 10%, and 25% are 1.576×10¹⁵, 1.894×10¹⁵, and 2.171×10¹⁵ ions/cm², respectively, indicating that the larger the deformation, the more the helium retention in the alloy.

• Experimental Research on High-Temperature Thermo-mechanical Behavior of Self-Developed New Type Zirconium Cladding Under Loss-of-Coolant Accident

  Guo Xiaoming, Qian Libo, Luo Yuejian

  2025,54(7):1802-1809 DOI: 10.12442/j.issn.1002-185X.20240727

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  Abstract:High-temperature thermo-mechanical experiments were conducted to investigate the behavior of self-developed new type zirconium cladding under loss-of-coolant accident (LOCA) conditions, including high-temperature oxidation, high-temperature creep, high-temperature burst, and embrittlement experiment. Results show that the high-temperature oxidation rate of self-developed new type zirconium cladding is comparable to that of ZIRLO, M5, and Zr-4 cladding when the oxidation temperature exceeds 1000 °C, which can be estimated by Cathcart-Pawel model. Notably, the self-developed new type zirconium cladding exhibits significantly lower high-temperature creep-burst strain than M5 and Zr-4 cladding, which can decrease fuel assembly blockage during LOCA, thus contributing to a more favorable outcome in LOCA analysis. Additionally, the embrittlement criteria of the self-developed new type zirconium cladding meet the requirements of a peak cladding temperature of ≤1204 ℃ and the maximum cladding oxidation rate of ≤17%.

• Multi-scale Simulation of Influence of Fission Fragments on Zr Elastic Modulus

  Sun Zhipeng, Peng Danmin, Zhang Zikang, Liu Guisen, Jiang Linfeng, Li Yuanming, Tang Chuanbao, Shen Yao

  2025,54(7):1810-1816 DOI: 10.12442/j.issn.1002-185X.20240229

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  Abstract:Based on first-principles, phase field method, and elastic self-consistent theory, the influence of fission fragments on the Zr elastic modulus was analyzed through the multi-scale simulation. This research revealed the influence of the fission fragment elements and irradiation voids on the Zr elastic modulus. Results show that the fission fragment Xe dissolves in Zr matrix can reduce the elastic modulus, while the effect of irradiation voids on the elastic modulus is relatively small. Meanwhile, the quantitative relationship model was established between the elastic modulus (E) and the changes in irradiation damage dose (D) and temperature (T), . This work lays a technical foundation for the refined analysis of the mechanical properties of Zr alloys after irradiation.

• Effect of Y on High Temperature Steam Oxidation Behavior of Fe13Cr5Al Alloy

  Zhang Wenhuai, Yao Meiyi, Wang Haoyu, Wang Shaohan, Hu Lijuan, Xu Shitong, Xie Yaoping

  2025,54(7):1817-1827 DOI: 10.12442/j.issn.1002-185X.20240278

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  Abstract:Two types of Fe13Cr5AlxY with x=0, 0.3 (wt%) alloys, denoted as 0Y and 0.3Y, respectively, were prepared in a vacuum non-consumable arc furnace and exposed in 1000 and 1200 ℃ steam for 2 h. The high temperature oxidation behavior of the alloys was studied by thermogravimetric analyzer with steam generator. The microstructure and composition of the oxide film before and after oxidation were analyzed by XRD, FIB/SEM, EDS, and TEM. Results show that the addition of Y can refine the grains of FeCrAl alloys and form the spherical or elliptical hcp-Al₃Fe₁₄Y₂ second phase. The oxidation kinetics of the Fe13Cr5AlxY (x=0, 0.3, wt%) alloys oxidized in 1000 and 1200 ℃ steam for 2 h follows a parabolic growth law. The addition of Y can decrease the oxidation mass gain rate of the alloys. The oxide film of the two alloys is mainly composed of α-Al₂O₃ and a small amount of Fe oxide exists on the outside of oxide film. The second phase in the oxide film of 0.3Y alloy is oxidized into YAlO₃, Fe₂O₃ and Fe(Cr, Al)₂O₄. The ridged oxide film is formed on the surface of 0Y alloy. The oxide film of the alloy peels off from the substrate under oxidation at 1200 ℃. The oxide film on 0.3Y alloy is smooth and has good adhesion to the matrix. Therefore, the formation of the ridged oxide film is inhibited by adding Y, which can reduce the oxidation mass gain rate and enhance the high-temperature steam oxidation resistance of the alloy.

• Current Status and Development Trends of Artificial Intelligence in the Field of Nuclear Fuel and Materials

  Zhang Tao, Jiao Yongjun, Liu Zhenhai, Qiu Xi, Xiang Yilong, Huang Haoyue, Lan Xun, Xin Yong, Li Yuanming

  2025,54(7):1882-1894 DOI: 10.12442/j.issn.1002-185X.20240695

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  Abstract:With the rapid development of artificial intelligence (AI), its application in the field of nuclear fuel and materials is gradually becoming a new driving force for the advancement of nuclear energy technology. This article comprehensively reviews the current state of AI research in the field of nuclear fuel and materials and conducts an in-depth analysis of future development trends. It first introduces AI methods applied to scientific research, discussing from two aspects: network architecture and learning paradigms. Next it systematically summarizes the current state of AI applications in performance prediction at the material and structure levels of nuclear fuel materials, design optimization of materials and structures, and computer vision in fuel production and operation. The review then looks forward to the future development trends of the combination of AI with nuclear fuel and materials. At the algorithm level, it discusses methods to enhance the interpretability of machine learning models, quantify uncertainty, and the importance of limited supervised learning technology in reducing data requirements. At the application level, it discusses key technologies such as acceleration of multi-scale multi-physics field simulations, topological optimization and generative design, universal pre-trained models for nuclear material properties, and automated laboratories. Finally, several suggestions are proposed to further promote the application of AI in the field of nuclear fuel and materials.

• Research Progress of High-Efficiency Solid-State Neutron Moderator Materials

  Guan Jingyu, Shen Teng, Liu Guoming, He Kai, Jiang Xiaochuan, Qi Anzhou, Dong Hao

  2025,54(7):1895-1905 DOI: 10.12442/j.issn.1002-185X.20240633

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  Abstract:High efficiency solid-state neutron moderator materials are crucial component in micro-nuclear reactor. The main function of neutron moderator is to reduce the energy of neutrons produced by fission to a range that sustains further fission. Meanwhile, moderator materials are also one of the core structural materials in reactors. The application of high-temperature-resistant and efficient neutron moderator can help promote the development of miniaturization and mobility of micro nuclear reactors. Starting from the principle of moderators, several promising high-temperature resistant and efficient neutron moderators were summarized. The development prospects for different moderators were discussed, providing valuable guidance for subsequent researches and applications.

>Special Issue：titanium alloy

• Preparation of Ti-Al Alloys by Aluminothermic Reduction with MgF₂ Addition

  Tian Zhenyun, Chen Liangbin, Song Jingjing, Kang Jialong, Mao Hongxia, Qiu Guibao

  2025,54(7):1678-1686 DOI: 10.12442/j.issn.1002-185X.20240346

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  Abstract:The Ti-Al alloy was synthesized using the aluminothermic reduction of TiO₂, with CaO and MgF₂ serving as flux components. Investigations were conducted to ascertain the effects of MgF₂ content on the alloy-slag separation, alloy microstructure, composition, phase constitution, overall alloy yield, and aluminothermic reduction of TiO₂. Results indicate that MgF₂ enhances the separation of the alloy from slag and promotes the formation of the TiAl phase within the alloy matrix. Nevertheless, an overabundance of MgF₂ reduces the interfacial tension between the Al reductant and the slag, leading to significant loss of Al. This adversely affects alloy-slag separation, escalates the incorporation of oxide inclusions in the alloy, and severely reduces the recovery rate of alloy. Concurrently, the alloy has a phase transition from TiAl to Ti₃Al. The optimum condition for alloy-slag separation and alloy integrity is realized at the MgF₂ content of 10wt%. Kinetic analysis at this flux ratio determines the activating energy for the Al-TiO₂-CaO-MgF₂ system, which is 409.729 kJ/mol, and the order of kinetics is n=0.38.

• Kinetics and Characteristics of Isothermal Constant Volume Hydrogen Desorption in TC21 Alloy

  Yuan Baoguo, Luan Haibo, Wan Wei, Tian Xiang, Chen Mu, Chen Shuai, Su Chunshen

  2025,54(7):1697-1705 DOI: 10.12442/j.issn.1002-185X.20240289

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  Abstract:Hydrogen desorption kinetics and characteristics, residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method. Results show that hydrogen desorption temperature and initial hydrogen pressure affect hydrogen desorption characteristics of TC21 alloy. The hydrogen desorption process is mainly dominated by nucleation and growth process (kt=[-ln(1-α)]^2/3), chemical reaction process (kt=(1-α)^-1/2) and three-dimensional diffusion process (kt=[1-(1-α)^1/3]^1/2) when the hydrogenated TC21 alloy is dehydrogenated at temperatures of 700–940 °C. When the hydrogenated TC21 alloy releases hydrogen, the following relationship exists among the rate constants of each process: k (chemical reaction process)>k (nucleation and growth process)>k (three-dimensional diffusion process). The residual hydrogen content of the hydrogenated TC21 alloy after hydrogen desorption decreases gradually with the increase in hydrogen desorption temperature, and increases gradually with the increase in the initial hydrogen pressure. The activation energy of TC21 alloy in the process of hydrogen desorption is about 26.663 kJ/mol.

• Effect of Hot Deformation on α-Phase Precipitation and Mechanical Properties of Metastable β Titanium Alloy

  Gao Huixian, Shao Shan, Li Qinqin, Li Yuze, Wang Xiyu, Lei Qiang, Wang Tao, Luo Wenzhong, Liu Xianghong, Feng Yong

  2025,54(7):1706-1716 DOI: 10.12442/j.issn.1002-185X.20240316

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  Abstract:The effect of hot deformation on α-phase precipitation during the subsequent heat treatment, as well as the mechanical properties of TB18 Ti-alloy, was investigated. Results show that the round bar obtained by the dual-phase field forging of the cast ingot exhibits uniform composition distribution on its cross-section. However, various degrees of deformation are detected at different positions on the cross-section, which is attributed to the characteristics of the forging process. Under the forging condition, the microstructure is mainly composed of β-phase matrix and coarsened discontinuous primary α-phases. After solution and following artificial aging treatment, the primary α-phases disappear, while needle-like secondary α-phases precipitate in the matrix. Additionally, dispersed white zones are observed in the samples after aging, which are analyzed to be the precipitation-free zones of secondary α-phase. Despite a uniform compositional distribution among various regions, these dispersed white zones exhibit higher content and larger size in the positions that have undergone lower forging deformation. It indicates that the insufficient forging deformation inhibits the precipitation of the secondary α-phase, ultimately resulting in the lower strengthening effect by heat treatment. Thus, consistent with the characteristics of the forging process, a periodic variation of sample in strength is detected along the circumferential direction of the forged round bar.

• Effect of Heat Treatment on Microstructure and Mechanical Properties of High-Temperature Titanium Alloy Formed by Laser Selective Melting

  Liu Yi, Cai Yusheng, Jiang Muchi, Yang Xingyuan, Ren Dechun, Ji Haibin, Lei Jiafeng

  2025,54(7):1828-1837 DOI: 10.12442/j.issn.1002-185X.20240099

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  Abstract:High temperature titanium alloy was prepared by selective laser melting (SLM). The effect of heat treatment on the microstructure and mechanical properties of the alloy was studied via OM, SEM, XRD and mechanical tensile. The results show that the metastable acicular martensite α′ is transformed into α phase and β phase after solid solution heat treatment. With the increase in solution temperature, the ratio of length to width of α phase decreases, and fracture occurs along the grain boundary and phase boundary, and some α phase breaks from strips to short rods or equiaxed grains. The tensile strength and yield strength of the formed alloy decrease gradually with the increase in heat treatment temperature, while the elongation increases. Different from the case of the solid solution state, the second phase appears in the microstructure of the alloy after aging heat treatment, which leads to a significant increase in tensile strength and yield strength at room temperature, accompanied by a decrease in elongation. The aging temperature has little effect on the tensile properties of the alloy at room temperature and high temperature. After the solution of 945 ℃/2 h/AC and aging heat treatment of 700 ℃/8 h/AC, the alloy demonstrates good comprehensive mechanical properties.

• Preparation and Study of High-Strength and Wear-Resistant Titanium Alloys with “Hard Core-Strong Interface” at Moderate Temperature

  Li Juan, Liu Chang, Wang Lu, Li Dongting, Zhou Liyu, Liu Ying

  2025,54(7):1838-1846 DOI: 10.12442/j.issn.1002-185X.20240108

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  Abstract:To improve the hardness and wear resistance of titanium (Ti), it is proposed to introduce TiB₂ hard phase into pure Ti to accurately control the reaction process of the two components based on the discharge plasma sintering (SPS) technique, and to construct a TiB₂-TiB-Ti "hard-core-strong-interface" structure in Ti matrix that inherits the diffusion path of B element. Finally, a high hardness of 863.5 HV₅ at room temperature and 720.9 HV₅ at 400 ℃ is obtained with the addition of 40% TiB₂, which makes its friction performance better than that of commercial TC4 high-temperature titanium alloys under the same friction conditions in the temperature range from room temperature to 400 ℃. At the same time, thanks to its excellent bonding interface, the alloy also exhibits unique high-temperature and high-toughness properties, maintaining a high compressive strength of 1120 MPa and strain of about 11.7% at 400 ℃. The design idea of this study is inspiring and universal, which is expected to provide a new method for the research and development of new medium-high-temperature and high-toughness wear-resistant titanium alloys, and to promote the application of related materials in aerospace field.

>Materials Science

• Dynamic Behavior, Energetic Characteristics, and Failure Mechanism of High-Density W-Zr-Ti Reactive Alloy

  Qi Yuxuan, Mao Liang, Li Peiying, Liu Guitao, Tian Longnian, Jiang Chunlan

  2025,54(7):1687-1696 DOI: 10.12442/j.issn.1002-185X.20240338

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  Abstract:A high-density tungsten-zirconium-titanium (W-Zr-Ti) reactive alloy was prepared by powder metallurgy. This alloy exhibits high density, high strength, and violent energy release characteristics, resulting in outstanding penetration and ignition abilities. Dynamic impact experiment demonstrated its strain rate hardening effect, and the energetic characteristics were investigated by digital image processing technique and thermal analysis experiment. The results show that W-Zr-Ti reactive alloy performs compressive strength of 2.25 GPa at 5784 s^-1 strain rate, and its exothermic reaction occurs at about 961 K. Based on the explosion test and shock wave theory, thresholds of enhanced damage effect are less than 35.77 GPa and 5.18×10⁴ kJ/m² for shock pressure and energy, respectively. Furthermore, the transformation of fracture behavior and failure mechanism is revealed, which causes the increase in compressive strength and reaction intensity under dynamic loading.

• Effects of Ultrasonic Shot Peening on Surface Integrity and Corrosion Resistance of 6061-T6 Aluminum Alloy

  Li Kun, Wen Tengfei, Li Shaolong, Wang Cheng

  2025,54(7):1717-1726 DOI: 10.12442/j.issn.1002-185X.20240334

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  Abstract:According to surface morphology, microhardness, X-ray diffraction, and static contact angle experiments, the changes in the surface integrity and corrosion resistance of 6061-T6 aluminum alloy after ultrasonic shot peening (USP) were investigated. Results show that the grain size of the material surface is reduced by 43%, the residual compressive stress has an increasing trend, the roughness and hardness are increased by approximately 211.1% and 35%, respectively. And the static contact angle is increased at first, followed by a slight decrease. Weighing, scanning electron microscope, and energy dispersive spectrometer were used to study the samples after a cyclic corrosion test. Results show that USP reduces the corrosion rate by 41.2%. A model of surface corrosion mechanism of USP is developed, and the mechanism of USP to improve the corrosion resistance of materials is discussed. The introduction of compressive residual stresses, grain refinement, increased grain boundaries, increased hardness, and increased static contact angle are the main factors related to the improvement of corrosion resistance in most materials, while increased roughness tends to weaken surface corrosion resistance.

• Effect of GPLs on Grain Size of WC in WC-Co-GPLs Cemented Carbides: Refinement Mechanism

  Li Meng, Wei Dong, Hu Huixuan, Wu Weiguo, Zhong Sisi, Gong Manfeng, Zhang Chengyu

  2025,54(7):1727-1732 DOI: 10.12442/j.issn.1002-185X.20240318

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  Abstract:The influence of graphene platelets (GPLs) on the WC grain size of WC-Co-GPLs cemented carbide prepared by low-pressure sintering was investigated. The role of GPLs in refining WC grains was explored by characterizing grain size and phase distribution. Results show that the addition of GPLs leads to significant grain refinement of WC and the more uniform distribution of WC grain size. When the content of GPLs is 0.10wt%, the average WC grain size in the cemented carbide is 0.39 μm, which is 32% lower than that in WC-Co. However, the shape of WC grains is almost unaffected, while the mean free path of Co decreases. The grain refinement of WC is attributed to the homogeneous distribution of GPLs between WC/WC and WC/Co grain boundaries, which hinders the solution and precipitation process of WC in liquid phase Co, as well as the migration and growth of WC grains. Additionally, GPLs can serve as heat transfer plates in materials to improve cooling efficiency, thus inhibiting the growth of WC grain.

• Microstructure Evolution and Deformation Mechanism of DZ125 Ni-based Superalloy During High-Temperature Creep

  Li Yongxiang, Tian Ning, Zhang Ping, Zhang Shunke, Yan Huajin, Zhao Guoqi

  2025,54(7):1733-1740 DOI: 10.12442/j.issn.1002-185X.20240279

  Abstract(0) HTML(0) PDF(1.61 M)( 0)

  Abstract:The microstructure evolution and deformation mechanism of a DZ125 superalloy during high-temperature creep were studied by means of microstructure observation and creep-property tests. The results show that at the initial stage of high-temperature creep, two sets of dislocations with different Burgers vectors move and meet in γ matrix channels, and react to form a quadrilateral dislocation network. And γ′ phases with raft-like microstructure are generated after the formation of dislocation networks. As creep progresses, the quadrilateral dislocation network is gradually transformed into hexagonal and quadrilateral dislocation networks. During steady stage of creep, the superalloy undergoes deformation with the mechanism that a great number of dislocations slip and climb in the matrix across the raft-like γ′ phases. At the later stage of creep, the raft-like γ′ phases are sheared by dislocations at the breakage of dislocation networks, and then alternate slip occurs, which distorts and breaks the raft-like γ′/γ phases, resulting in the accumulation of micropores at the raft-like γ′/γ interfaces and the formation of microcracks. As creep continues, the microcracks continue to expand until creep fracture occurs, which is the damage and fracture mechanism of the alloy at the later stage of creep at high temperature.

• Solidification Structure and Quasicrystal Regulation of Mg-Zn-Gd Casting Alloys

  Wang Chunhui, Yang Guangyu, Qin He, Kan Zhiyong

  2025,54(7):1847-1856 DOI: 10.12442/j.issn.1002-185X.20240112

  Abstract(2) HTML(0) PDF(5.24 M)( 0)

  Abstract:The I phase (Mg₃Zn₆Gd, icosahedral quasicrystal phase) is widely considered as the strengthening phase in Mg-Zn-Gd system alloys, providing more significant improvements in the mechanical properties compared to the W phase (Mg₃Zn₃Gd₂, cubic phase). However, both the W phase and the I phase typically coexist in the as-cast Mg-Zn-Gd alloy, thereby weakening its mechanical properties. There has been limited systematic research dedicated to investigating the crystallization mechanism of these phases during solidification. In this study, the equilibrium solidification and Scheil solidification paths of Mg-xZn-2Gd (x=0–12, wt%) alloys were calculated by Thermo-Calc software. The effects of cooling rate and alloy composition on the fraction of the I phase were studied. The results show that the equilibrium solidification structure of the alloy with a Zn/Gd atomic ratio of 6.0 only contains the I phase. In contrast, limited solute diffusion in the solid phase hampers the transformation of the W phase into the I phase during non-equilibrium solidification, forming a mixed structure composed of both the W phase and the I phase. The variation of cooling rate and alloy composition affects the solute enrichment rate in the Liquid during the solidification process of the primary α-Mg phase and alters the solute content and temperature of the residual Liquid when the secondary phase begins to crystallize, and influences the type and fraction of the secondary phase as determined by the solidification driving force. The increased solidification cooling rates and Zn/Gd atomic ratio inhibit the W phase and promote the formation of the I phase during Mg-Zn-Gd alloy preparation, resulting a higher proportion of the I phase in the alloy.

• Effect of Granularity on Electrical Conductivity of Cold-Pressing Sintered Strontium Vanadate Bulks

  Chen Jianbo, Yang Xiaojiao, Yang Ningjia, Niu Yibo, Ouyang Linfeng, Liu Ying

  2025,54(7):1857-1863 DOI: 10.12442/j.issn.1002-185X.20240114

  Abstract(0) HTML(0) PDF(7.74 M)( 0)

  Abstract:Kilogram-scale micro-nano SrVO₃ powder was produced by the sol-gel method combined with hydrogen reduction and heat treatment. Then SrVO₃ bulks were prepared by cold pressing and sintering the sifted powders using different mesh sizes (unsifted powder, 100 mesh, 200 mesh, and 300 mesh). The thermal stability of SrVO₃ powder and bulks under air was investigated, and the effects of powder granularity sifting on granularity and distribution of their raw material, bulk grain size, and electrical conductivity were also evaluated. The results show that SrVO₃ bulk has better thermal stability in air than SrVO₃ powder; the temperature at which oxidative mass gain occurs is enhanced from 335 °C for the powder to 430 °C for the bulk. The mean particle size of the raw material powders decreases, the electrical conductivity of the related cold-pressing sintered bulks is significantly raised, and the conductivity of the powders rises with the increase in granularity sifting mesh. Granularity sifting can be used to acquire smaller and more uniform raw powder materials, which increases the density of the bulks produced by cold-pressing sintering. Furthermore, more effective routes for the conduction of electric charge are established and the conductivity of the prepared SrVO₃ bulk reaches 20 000 S/cm, which is 37% higher than that of the bulk produced by unsifted powder. Granularity sifting is essentially the optimization of the particle size of the raw material. More sifting of the particle size of the SrVO₃ powder is expected to yield improved performance of bulk material, providing the foundation for its use in transparent conductive films, semiconductor devices, sensors, and other areas.

• Thermal Deformation Characteristics of Diffusion-Bonded Interface Region of GH4169 Alloy

  Xu Qinsi, Zhang Mingchuan, Liu Yi, Cai Yusheng, Mu Yiqiang, Ren Dechun, Ji Haibin, Lei Jiafeng

  2025,54(7):1864-1872 DOI: 10.12442/j.issn.1002-185X.20240118

  Abstract(1) HTML(0) PDF(4.01 M)( 0)

  Abstract:The thermal deformation behavior of the GH4169 alloy diffusion-bonded region was investigated using a Gleeble 3800 thermal-mechanical simulation test machine at deformation temperatures of 1213–1333 K with strain rates of 0.01–10 s^-1. The results show that the "bond line" in the diffusion bonding region of GH4169 alloy can be effectively eliminated through thermal deformation. The evolution of the δ phase in the diffusion bonding interface region is affected by deformation conditions. When the deformation temperature is lower than the solution temperature of the δ phase, the residual spheroidized δ phase prevents the growth of recrystallization nucleation grains and affects the subsequent recrystallization process. The spheroidization degree of the δ phase can be enhanced by reducing the strain rate. When the deformation temperature exceeds the dissolution temperature of the δ phase, the dissolution of the δ phase creates an extra driving force for recrystallization, thereby significantly enhancing the extent of recrystallization. A hyperbolic sinusoidal Arrhenius constitutive equation with incorporating strain compensation was used to describe the correlation between flow stress and deformation conditions in the diffusion-bonded region of the GH4169 alloy. The calculated values of the constitutive equation agree with the experimental values. According to the dynamic model of the GH4169 alloy diffusion bonded region, the optimal processing parameters are determined as the deformation temperature between 1310–1333 K, and the strain rate between 0.01–0.05 s^-1.

• Effects of Hf Microalloying on Oxidation Behavior of K4800 Nickel-Based Superalloy

  Lu Jianqiang, Wang Linlin, Ou Meiqiong, Hou Kunlei, Wang Min, Wang Ping, Ma Yingche

  2025,54(7):1873-1881 DOI: 10.12442/j.issn.1002-185X.20240125

  Abstract(0) HTML(1) PDF(6.65 M)( 1)

  Abstract:The effect of Hf on high-temperature oxidation behavior of K4800 nickel-based superalloy was studied. The results show that the oxidation kinetics curves of K4800 and K4800+0.25Hf alloys obey parabolic law during thermostatical static oxidation at 800 and 850 ℃.However, the initial static oxidation rate of K4800+0.25Hf alloy (0.026 g/m²·h at 800 °C for 20 h and 0.061 g/m²·h at 850 °C for 20 h) is lower than that of K4800 alloy (0.041 g/m²·h at 800 °C for 20 h and 0.066 g/m²·h at 850 °C for 20 h). The oxide layer of the two experimental alloys consists of outer oxide layer and an inner oxide layer. The outer oxide layer primarily consists of dense Cr₂O₃, while the inner oxide layer mainly contains dendritic Al₂O₃. However, with the increase in Hf content from 0wt% to 0.25wt%, the thickness of the Cr₂O₃ outer oxide layer decreases from 2.71 μm to 2.17 μm after oxidation at 800 °C for 1000 h and from 5.83 μm to 4.09 μm after oxidation at 850 °C for 1000 h. The results of EPMA analysis indicate the formation of HfO₂ at the grain boundary of the oxide layer in the K4800+0.25Hf alloy, promoting the formation of Al₂O₃ around HfO₂ and accelerating the growth of Al₂O₃. The presence of Al₂O₃ and HfO₂ at the grain boundary contributes to the reduction of the outward diffusion rate of Cr³⁺ and the delaying of thickening of the Cr₂O₃ oxide layer. Consequently, the trace addition of Hf enhances the oxidation resistance of the K4800 alloy.

• Research Progress in Electrochemical Synthesis and Purification of Rare Metal Alkoxides

  Yang Shenghai, Li Yibo, Xia Xinbing, Chen Yongming, Lai Yanqing, Tian Zhongliang, Huang Liangcai, Wang Changhong

  2025,54(7):1906-1916 DOI: 10.12442/j.issn.1002-185X.20240129

  Abstract(0) HTML(1) PDF(7.20 M)( 0)

  Abstract:Rare metal alkoxides, as key precursors for gate dielectric materials in semiconductor chips, particularly involving the oxides of rare metals such as zirconium, hafnium, tantalum, and niobium, play a crucial role in high-tech fields. Although the traditional halide synthesis method for preparing alkoxides has been widely used, it has drawbacks such as complex processes and low yield. In contrast, electrochemical synthesis is gaining attention due to its simpler process and higher yield, offering significant cost advantages over traditional methods and enhancing the economic benefits for related enterprises. The review summaries our group, research over the past two decades on the electrochemical synthesis of zirconium, hafnium, tantalum, and niobium alkoxides was reviewed, including studies on the electrode reaction mechanisms, determination of process parameters, and physicochemical characterization of the products. The aim is to drive the optimization of the electro-synthesis technology for rare metal alkoxides, provide solid technical support to relevant enterprises, and accelerate the rapid development of integration of production, education, research, and application.

Online First

• Stability and effect of primary carbides in Inconel 718 superalloy service turbine disk

  Zhang Yan Lin, Chen Shuo, Jiang He, Dong Jian Xin

  Available online:June 19, 2025  DOI: 10.12442/j.issn.1002-185X.20250173

  Abstract(30) PDF(2.76 M)(33)

  Abstract:Taking an Inconel 718 (GH4169) turbine disk with an accumulated service time of approximately 60,000 hours from a specific model of aircraft as the research object, this study systematically investigates the microstructure of various regions of the service turbine disk. 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 undergone noticeable decomposition. The content decreased from 0.166 wt.% to 0.106 wt.%, and the morphology gradually changed from sharp and regular blocky shapes at the interface to irregular near-circular shapes. The nano-hardness decreased, and there was a significant redistribution of elements, with Nb, Ti, and C elements 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 the 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.

• 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

  Available online:June 19, 2025  DOI: 10.12442/j.issn.1002-185X.20250219

  Abstract(25) PDF(2.69 M)(19)

  Abstract:In the face of harsh and complex oil and gas resources exploitation environment, it is urgent to explore titanium alloy oil well pipes with high strength and toughness service performance. In this paper, 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 process. The tensile properties at room temperature and impact properties at -20 °C were tested. The effects of microstructure evolution on mechanical properties were analyzed by SEM, XRD and TEM. The results show that the size of αC and the average grain thickness of αL increase significantly, and the orientation and uniformity of the microstructure are also significantly enhanced after the deformed Widmanstatten structure of the RP sample is aged in the two-phase region (STA910). The tensile strength, yield strength and elongation of RP samples are 904 MPa, 793 MPa and 14.2 %, respectively. The impact energy and impact toughness at -20 °C are 66.2 J and 82.7 J/cm2, respectively. After solution and aging in the two-phase region, the tensile strength, yield strength and elongation of STA910 sample increased to 984 MPa, 904 MPa and 16.2 %. The impact energy and impact toughness at-20 °C decreased slightly, but still maintained at 52.8 J and 66.2 J/cm2. The α/β interface is increased by the precipitation of αS 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 of β phase stability and the precipitation of αS and ω phases in βt lead to the decrease of impact properties of the alloys.

• Study on 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

  Available online:June 13, 2025  DOI: 10.12442/j.issn.1002-185X.20250166

  Abstract(34) PDF(1.18 M)(42)

  Abstract:Porous CoCrNi MEA with porosity of 60.6% -78.1% and pore size of 1.8 -2.4mm were prepared by powder sintering-dissolution method. 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 500s_-¹ strain rate. The yield strength increases by 52.8% (22.9 MPa to 35.0MPa) with the increase of strain rate from 200s_-¹ to 800s^_-1. The dynamic yield strength increases by 25% compared with the quasi-static yield strength. The energy absorption value reaches 35.4 ~14.5MJ/m^₃ (6.6% ~ 14.0% higher than the quasi-static), and the maximum ideal energy absorption efficiency is close to 0.9. At the same time, under the condition of low temperature (-100°C), the elastic modulus and platform stress are increased by 2.4% ~10.5% and 2.5% ~9.8%, respectively, compared with room temperature. The energy absorption value is 41.3 ~15.2MJ/m^₃, which is twice that of magnesium alloy foam, and the maximum ideal energy absorption efficiency remains 0.8. In summary, the porous CoCrNi MEA has both dynamic strengthening and low-temperature strengthening characteristics, and 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.

• 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

  Available online:June 13, 2025  DOI: 10.12442/j.issn.1002-185X.20250198

  Abstract(27) PDF(1.37 M)(54)

  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 focuses on the nickel-based superalloy FGH96 and the titanium alloy TC4, and investigates the effects of atomization pressure and gas temperature on the particle size, morphology, and hollow powder content of the alloys. The study combines atomization experiments with powder characterization. The results show that at a gas temperature of 25°C, increasing the atomization pressure from 2.5 MPa to 4.0 MPa, reduces the median particle size (D??) from 96.3μm to 75.5μm. The sphericity reaches its maximum value 0.9805 at an atomization pressure of 3.5MPa. The powder volume porosity also exhibits a trend of first increasing and then decreasing. At an atomization pressure of 4.0MPa, as increasing the gas temperature to 100°C the powders further refine, with the D?? values for FGH96 and TC4 powders decreasing to 63.8μm and 86.0μm, 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.

• Effect of cold rolling deformation on grain morphology and damage resistance of Al-Cu-Li alloy

  Hong Xin, Yan Lizhen, Zhang Yongan, Li Xiwu, Li Zhihui, Wen Kai, Geng Libo, Qi Bao, Li Ying, Xiong Baiqing

  Available online:May 09, 2025  DOI: 10.12442/j.issn.1002-185X.20240846

  Abstract(90) PDF(1.46 M)(159)

  Abstract:Metallographic microscopy (OM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and room-temperature tensile, tearing, and fatigue crack extension experimental methods were used to investigate the effect of the four final cold-rolling deformations （13%、23%、46%、68%） after intermediate annealing on the grain morphology and damage resistance properties of the Al-3.9Cu-0.74Li-0.68Mg alloy sheets. The results indicate that with increasing cold-rolling reduction after intermediate annealing, complete recrystallization occurred in the sheets after solution treatment, leading to a significant reduction in the average grain size and aspect ratio, with grains tending to become more equiaxed. The primary precipitates in the aged alloy were T1 phase, and the size, number density, and volume fraction of T1 phase showed little variation among the four reduction levels. Quantitative calculations of the contributions of different strengthening mechanisms to the yield strength revealed that the strengthening of the alloys with the four reduction levels was mainly attributed to the precipitation strengthening of T1 phase, contributing 336-367 MPa to the yield strength. With increasing cold-rolling reduction, the fatigue crack growth rate of the sheets increased, resulting in deteriorated fatigue performance, while the fracture toughness showed an upward trend. Fine grains were beneficial for improving fracture toughness but detrimental to fatigue property.

• The effect of TiC content on the microstructure and mechanical properties of Mo-based composites

  Yu Shan, WangYuqi, HuangYao, ZhangHexin, ZhaoChengzhi

  Available online:May 09, 2025  DOI: 10.12442/j.issn.1002-185X.20240848

  Abstract(42) PDF(1.70 M)(153)

  Abstract:This study investigates the influence of titanium carbide (TiC) content on the microstructure and mechanical properties of molybdenum (Mo)-based composites, aiming to provide a scientific basis for the development of high-performance, heat-resistant molybdenum materials for aerospace engines. TiC/Mo composites containing 10%, 20%, and 30% TiC were prepared using spark plasma sintering (SPS) technology. The results indicate that the strengthening mechanisms of TiC/Mo composites are primarily attributed to intragranular particle strengthening and grain boundary strengthening. At elevated temperatures, TiC diffuses into the Mo matrix, forming a transition zone of measurable width at the interface of the two phases. XRD analysis confirms that this transition zone comprises (Ti, Mo)C. The crystal lattices of the TiC and Mo phases exhibit strong bonding, which is further corroborated by atomic-scale observations. Tensile and hardness tests reveal that TiC/Mo composites with 10 wt% and 20 wt% TiC demonstrate superior mechanical properties. The fracture behavior of these composites is primarily governed by the propagation of intergranular microcracks, which is influenced by the competition between intergranular and intragranular crack development. This study provides critical insights into the coupling effects of intergranular and intragranular TiC particles on the mechanical performance of TiC/Mo composites.

• Corrosion resistance enhancement of GH3625 alloy tube in high-temperature KCl-MgCl₂ molten salt environment via Microstructure tailoring

  Gao Yubi, Wang Xin, Zhen Bing, Xu Jiayu, Ding Yutian

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240588

  Abstract(59) PDF(9.52 M)(237)

  Abstract:The influence of microstructure with different ratios of twin boundaries on the corrosion behavior of GH3625 alloy pipes in high-temperature (600 ℃~800 ℃) KCl-MgCl₂ molten salt was studied using EBSD, XRD, SEM, and EDS methods. The results showed that with the increase of annealing temperature, the proportion of annealing twin boundaries in the equiaxed grains of GH3625 alloy tube increased, and the higher the proportion of twin boundaries in the alloy at the same corrosion temperature, the better its high-temperature resistance to KCl-MgCl₂ molten salt corrosion. Meanwhile, as the corrosion temperature increases, the high-temperature resistance of the same group of samples to KCl-MgCl₂ molten salt corrosion decreases. In addition, under the same grain size conditions, the higher the proportion of annealing twin boundaries in GH3625 alloy tubes, the better their high-temperature resistance to KCl-MgCl₂ molten salt corrosion. This is mainly attributed to the high-density stable annealing twin boundaries themselves have excellent corrosion resistance, and the triple junction containing twin boundaries breaks the connectivity of the original high angle grain boundary network, suppressing the corrosion of the grain boundaries.

• Anisotropy Control of Titanium Alloy Porous Materials Based on the Modified Gibson-Ashby Model

  Ding Chao, Xie Tenglong, Xu Shenghang, Huang Minghao, Zhang Zhaoyang, Yang Xin, Tang Huiping, Zhao Yang

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240596

  Abstract(93) PDF(1.91 M)(254)

  Abstract:According to the varying load in different directions, the anisotropy control of porous materials can significantly enhance the load-bearing efficiency of materials, thus better addressing the need for lightweight designs. In this paper, a modified G-A model for srtut-based porous materials accounting for the geometric parameters was established by taking G7 and BCCZ types of TC4 porous materials as examples. This model could serve as a guide for the precise control of anisotropy for strut-based porous materials. By adjusting the geometric parameters of common unit cells, a range of anisotropic porous materials with similar configurations but distinct properties were created. The influence of cellular geometric parameters on the anisotropic mechanical properties and failure modes of these materials was investigated through both vertical and lateral compressive tests, which also validated the efficacy of our modified model. The research results indicated that the mechanical properties of strut-based porous materials were primarily determined by the aspect ratio and the inclination angle of their struts. By fine-tuning the inclination angle of these struts, the anisotropic mechanical properties of the porous materials can be effectively modulated. At identical density levels, it could result in a substantial increase in the vertical compressive strength of G7 and BCCZ types of TC4 porous materials by 105% and 45%, respectively, with only a minor reduction in lateral compressive strength of 16% and 13%, by increasing the inclination angle of the diagonal struts from 35° to 55°.

• Ammonium tungstate evaporation crystallization purification based on single factor combined with Box-Behnken method

  Xiao Lairong, Li Shaohao, Zhao Xiaojun, Wang Xinyue, Wang Zihao, Cai Zhenyang, Lu ekang, Liu Sainan, Li Qingkui

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240615

  Abstract(130) PDF(1.31 M)(230)

  Abstract:The single factor + Box-Behnken response surface method was used to optimize the impurity removal process of ammonium tungstate solution evaporation crystallization method to prepare higher purity ammonium paratungstate (APT). Firstly, in order to reduce the total content of four impurities (Na, K, S, Mo elements) in APT, the preferred range of crystallization temperature, stirring speed and initial concentration of ammonium tungstate solution was preliminarily determined by single factor method. Secondly, the evaporation crystallization impurity removal process of APT was further optimized by Box-Behnken response surface method, and the mutual influence of three factors on the total amount of four impurities in APT was studied. The results show that the order of influence of three factors on the total amount of four impurities is : initial concentration of ammonium tungstate solution > evaporation temperature > stirring speed ; the optimum process conditions were as follows : evaporation temperature 94 °C, stirring speed 1.25 m/s, initial concentration of ammonium tungstate solution 73 g/L. Under the experimental conditions, the total content of the four impurities in the prepared APT was reduced to 39.351 ppm, and the relative error with the optimal prediction value of the response surface method model was only 4.110 %, and the purity of APT reached 4N. The generated APT crystal is a columnar cuboid morphology with a small amount of broken crystals. The layered structure is obvious, the particle size distribution is uniform, and the grain refinement is obvious.

• New opportunities in refractory niobium alloys via additive manufacturing：A review

  Lan Hang, Lu Kaiju, Tong Yonggang, Wang Jie, Qiao jinjin, Chen Yongxiong, Hu Zhenfeng, Liang Xiubing

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240617

  Abstract(110) PDF(2.96 M)(257)

  Abstract:Due to their low density, good room-temperature plasticity, and excellent high-temperature toughness, refractory niobium alloys have been used in hot-end components in the aerospace field. However, niobium alloys prepared by traditional casting methods are difficult to process parts with complex geometries, and met problems like long processing period, expensive price and high buy-to-fly ratio. The rapid development of additive manufacturing technology in recent years not only reduces the production period and cost, but also obtains superior mechanical properties, which brings new opportunities for the further application of niobium alloys. To this end, this paper reviews the current state-of-art research on additively manufactured niobium alloys, focusing on the laser and electron-beam additive manufacturing of two generations of typical niobium alloys, namely C-103 and Nb521, in particular with regard to the modulation of their mechanical properties and microstructure. In addition, common types of niobium alloys and additive manufacturing methods are briefly introduced. Finally, the future direction of additively manufactured niobium alloys and the problems that still need to be solved are proposed. By reviewing the field of additively manufactured niobium alloys, this paper provides a reference for the further application of niobium alloys in the aerospace field for hot-end components of complex structures.

• Research on BJ3DP and sintering densification of AlTiCrNiCu low-density high entropy alloy prepared by mechanical alloying

  Zhu Dezhi, Chen Haipeng, Cai Liangfu

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240636

  Abstract(108) PDF(2.11 M)(220)

  Abstract:The binder jetting 3D printing (BJ3DP) process is currently a research hotspot. Generally, the powder bed printing process requires spherical powders, which limits the preparation and printing of some HEA powders with large melting point differences. This study mainly focuses on the BJ3DP printing-sintering behavior of non-spherical particles. The results showed that the near-spherical AlTiCrNiCu low-density HEA powder with BCC structure was prepared by mechanical alloying, with a particle size ranged from 6.72 to 67.52 μm and an average particle size of 21.17 μm, which met the requirements of the BJ3DP printing process. The results of the orthogonal experiment indicate that when the binder saturation is 60%, the layer thickness is 120 μm, and the powder feeding speed is 15 pps, the green density of BJ3DP printing is the highest (about 44.7%). After sintering at 1190℃ for 4 hours, the density of the green body reaches 91.6%. The AlTiCrNiCu low-density HEA has a multiphase structure, with the B2 phase as the matrix, including BCC, FCC, and a small amount of L2₁ phase. The AlTiCrNiCu low-density HEA has high compressive properties, with a yield strength and compressive strength of approximately 840 MPa and 960 MPa, respectively. The research results provide ideas and reference for the BJ3DP printing and sintering of non-spherical metal powders, further expanding the application scope of metal powder BJ3DP printing and forming.

• Non-uniform Microstructure and High Temperature Coordinated Deformation Behavior of 2A97 / 5A06 Dissimilar Aluminum Alloy Friction Stir Butt Welded Plate

  Qin Zhonghuan, Wu Aiping, Yin Hongliang, Li Baoyong, Liu Qi, Wu Yong

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240637

  Abstract(96) PDF(2.83 M)(239)

  Abstract:In this paper, the non-uniform microstructure and high temperature coordinated deformation behavior of 2A97 / 5A06 dissimilar aluminum alloy friction stir welded plate were studied. The microstructure of each area of the welded joint was observed, and the high temperature mechanical properties of each area and the whole joint was studied. It was found that the grains in the weld nugget zone of 2A97 and 5A06 were fine. The grain size of each region on the 2A97 side was small and basically close, and the grain size of each region on the 5A06 side was slightly larger and the difference was obvious. Under the process parameter of 430 °C and 10_-3 s_-1^{, the} high temperature properties of 2A97 and 5A06 base metals are better, and the elongations are 278.8 % and 118.6 %, respectively. The strength and elongation of the nugget zone of the joint are 18.4 MPa and 176.1 %, respectively, which are between 2A97 and 5A06. The strength is about 2 times that of the 2A97 base metal, and the elongation is about 1.5 times that of the 5A06 base metal. The overall performance shows an obvious superposition principle. The deformation resistance of each region is different. The vertical weld specimen fractured after concentrated deformation in the 2A97 thermo-mechanically affected zone. After correction, the flow stress was slightly higher than that of the base metal and the elongation was close to that of the base metal. The grain size and flow stress of each region after welding meet the creep equation. The smaller the grain size, the lower the flow stress.

• Research Progress on the Cathodic Arc Ablation Mechanisms and Ablation-resistant Cathodes

  Guan Weimian, Liang Xinzeng, Liu Lingling, Zhao Liang, Jin Yinling, Xu Jiwen, Jia Dawei, Liu Jiabin

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240643

  Abstract(293) PDF(2.66 M)(224)

  Abstract:Cathode arc ablation limits the maximum operating time of arc plasma applications. Developing cathodes with extended service life is essential for improving the operating capability of current facilities, such as arc heaters and plasma welding. Understanding cathodic arc ablation behaviors and failure mechanisms is key to developing high-performance cathodes. This article first analyses the intricate arc ablation process of metallic cathodes and introduces failure mechanisms of sputtering, oxidation, and inhomogeneous ablation resulting from cathode spots. Furthermore, it reviews the recent advancements in improving cathode ablation resistance, including grain refinement, low work function addition, and gradient functionalization. In the final section, the future development of metallic cathodes is prospectively discussed based on in-situ observation of cathode spots, the construction of multi-field cathodic arc ablation model, and the establishment of a comprehensive cathode developing regime encompassing design, manufacturing, and testing processes.

• The Microstructure and Room Temperature Mechanical Properties of K4750 Superalloy Prepared by Gravity Casting and Centrifugal Casting

  Yang Yiyan, Yang Guangyu, Zhang Zhao Zhong, Wu Hao, Zhang Jun, Jie Wan Qi

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240648

  Abstract(96) PDF(3.72 M)(184)

  Abstract:The microstructure and room temperature mechanical properties of K4750 superalloy prepared by gravity casting and centrifugal casting were investigated, which included the second phase distribution, grain size, element segregation, distribution of shrinkage defects, room temperature mechanical properties and fracture morphology. It was found that the as-cast K4750 superalloy had similar microstructures prepared by two casting methods, namely γ matrix phase, MC-type carbide within grains, fine and dispersed γ" phase, as well as MC-type and M23C6 type carbides at grain boundary. However, these precipitates size were found to be more refined in the centrifugal casting methods. The average grain size of as-cast K4750 superalloy also decreased from 4.52 mm in the gravity casting to 2.22 mm in the centrifugal casting. Meanwhile, the area fraction of shrinkage defects was reduced from 1.75% in the gravity casting to 0.27% in the centrifugal casting. The dendrites of the gravity casting superalloy arranged neatly, whereas the dendrites of centrifugal casting superalloy were broken, and the segregation of elements was reduced. The K4750 superalloy samples prepared by centrifugal casting exhibited excellent room temperature mechanical properties, with yield strength, ultimate tensile strength and elongation of 632 MPa, 938 MPa and 11.2%, respectively. Compared with the K4750 superalloy prepared by gravity casting, its ultimate tensile strength increased by 20.6%, which may attributed to the combination of grain refinement, γ" phase refinement and casting defects reduction.

• Microstructure and Properties of Dental Implant Zr-30Ti-xCu Alloys

  Chen Zhebin, Cui Yue, Hu Lijuan, Ma Runze, Xu Shitong, Yao Meiyi

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240651

  Abstract(103) PDF(3.00 M)(142)

  Abstract:Zirconium and its alloys have recently received considerable attention as candidate materials for dental implants due to its low modulus of elasticity, good corrosion resistance, and excellent biocompatibility. In this work, Zr-30Ti-xCu (x=0, 3, 7, mass fraction, %) alloys were designed by the valence electron concentration (VEC) theory. The microstructures of the alloys were characterized using SEM/EDS and TEM/EDS. The mechanical properties, corrosion behaviors, biocompatibility and antibacterial activities of the alloys were characterized through microhardness testing, room temperature tensile testing, electrochemical testing, contact angle testing, and antibacterial performance experiments. Results showed that after quenching at 650 ℃/15 min, the three alloy matrices were mainly composed of β phase. In the Cu-containing alloys, Zr2Cu second phase precipitated and the number of Zr2Cu particles increased with the increase of Cu content. With the increase of Cu content, the Vickers microhardness increased by 37 %, the contact angle decreased from 98.49° to 74.21° to improve the surface wettability. Meanwhile, it showed a significant inhibitory effect on Escherichia coli and Staphylococcus aureus, and enhanced the corrosion resistance of the alloy in physiological saline solution. The three alloys had low elastic modulus (67.8-78.9 GPa) and cytotoxicity, but their relationship with Cu content was not obvious. It can be seen that Zr-30Ti-xCu alloy exhibits excellent comprehensive properties, which can provide theoretical basis and guidance for the selection of new dental metal implants.

• Microstructure and Tribological Properties of Laser Cladding AlCoCrFeNi/WC High Entropy Alloy Gradient Composite Coatings

  Li Wenyu, Yang Weiming, Ma Yan, Liu Lichen, Zhang Xiang, Zhang Ping, Zhao Yuchen, Liu Haishun, 1

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240652

  Abstract(89) PDF(2.06 M)(228)

  Abstract:In order to improve the surface wear resistance of metal parts, this study quantitatively analyzed the effect of ceramic particle content on the microstructure evolution and mechanical properties enhancement mechanism of high-entropy alloy gradient coating, and prepared dense and uniform high-entropy alloy gradient composite coating with different WC content on 45# steel substrate by laser cladding technology. The results show that with the increase of WC content, the grain size of the coating decreases from 20.16μm to 7.71μm, and the grain shape changes from cellular to dendrite and equiaxed. In addition, the microhardness of the gradient composite coating is significantly increased, which is 3 times that of the substrate, and 1.4 times higher than that of the high-entropy coating without adding WC. The coating mainly consists of body-centered cubic phase and metal carbide, and the corresponding diffraction peak intensity increases gradually with the increase of WC content. The wear performance test results show that the coating exhibits the best wear resistance when the WC content is 20 %, and the friction coefficient and wear amount are 0.4680 and 0.16 mg, respectively, which are lower than the WC40 coating with the highest average hardness, indicating that maintaining appropriate toughness while improving the hardness of the coating is the key to achieve the optimization of the coating performance. This study provides a certain reference value for the study of the optimization of high entropy alloy coatings prepared by laser cladding.

• Progress and Prospects of High-Performance Cu-Ta Composites

  XingBo, HaoZiyan, WangPengfei, ZhangShengnan, LiangMing, LiChengshan, LiJianfeng, ZhangPingxiang

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240661

  Abstract(63) PDF(4.76 M)(292)

  Abstract:Cu-Ta composite with high strength, high electrical and thermal conductivity along with excellent thermal stability, is a promising candidate for applications in many fields, such as electrical devices, defense, rail transport, ultra-high field pulsed magnets and biomedical engineering. Extensive studies have been carried out to meet the application requirements, and significant results were achieved. This work provides a comprehensive review of recent developments in the fabrication methods, performance, and applications of Cu-Ta composites. Besides, the problems of present researches have been pointed out and development trends in future are prospected.

• Microstructure and Properties of Laser Additive Manufacturing TC4 Alloy regulated by Mo content

  Chen Zubin, Wang Xuhong, Tang Huaguo, Pan Kunming, Zhu Lilong

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240669

  Abstract(180) PDF(3.89 M)(78)

  Abstract:Due to the excellent mechanical properties and excellent biocompatibility, TC4 titanium alloy has been widely used in the aerospace and medical devices field. Laser additive manufacturing (LAM) is an important means of forming and manufacturing titanium alloys. Large numbers of columnar crystals and acicular martensite existed in additive manufacturing TC4 titanium alloy should be addressed, which lead to anisotropy and plasticity reduction of material properties. In this work, molybdenum (Mo) was selected to regulate the microstructure and improve the properties of additive manufacturing TC4 titanium alloy, and the effect of Mo content on the microstructure and properties of laser additive manufacturing TC4 titanium alloy was explored. With the addition of Mo element, TiAl3 phase is gradually precipitated from the alloy matrix, and its content increases with the increase of Mo content. When the Mo content reaches 8wt.%, fine and dispersed lamellar structure is distributed in the alloy, and the β phase content increases sharply, and both the maximum grain refinement degree and dislocation density obtained. With the Mo content increasing from 0 to 10wt.%, the tensile strength, hardness and corrosion resistance of the alloy increase first and then decrease while the elongation follows the opposite trend, the Young"s modulus decreases gradually. When Mo content is 8wt.%, the alloy obtains the best mechanical strength and plasticity, the tensile strength, elongation and Young"s modulus are 1065.6MPa, 11.5% and 55.4GPa, respectively, and the corrosion resistance of the alloy is improved. Overall, TC4-8Mo sample has excellent mechanical properties and good corrosion resistance, and has the potential to be used as human medical implant materials.

• Study on the Formation Mechanism of Bright Band during Forging of TC18 Alloy

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

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240804

  Abstract(96) PDF(4.07 M)(262)

  Abstract:A systematical analysis of the macro/microstructure, composition, and crystal orientation of the bright band were conducted using OM, SEM and EBSD methods, as well as Gleeble tests, to study the formation mechanism of bright band in forged TC18 alloy. The results show that: the bright bands in the center of TC18 alloy forgings correspond to β cube-grains in size of around 100mm; 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.

• Intelligent parameter decision-making and multi-objective prediction in multi-layer and multi-pass LDED process

  Yaguan Li, Zhenguo Nie, Huilin Li, Tao Wang, Qingxue Huang

  Available online:April 08, 2025  DOI: 10.12442/j.issn.1002-185X.20250065

  Abstract(106) PDF(1.27 M)(115)

  Abstract:The main parameters that characterize the morphology quality of multi-layer and multi-pass laser metal printed parts are the surface roughness and the error between the actual printing height and the theoretical model height. This study employed the Taguchi method to establish the correlation between process parameter combinations and multi-objective characterization of metal print morphology quality (height error and roughness). The signal-to-noise ratio (SNR) and grey correlation analysis method were used to predict the optimal parameter combination for multi-layer and multi-pass printing: laser power 800 W, powder feeding rate 0.3 r/min, step distance 1.6 mm, scanning speed 20 mm/s. Subsequently, we constructed the Genetic Bayesian-back propagation network (GB-BP) to predict multi-objective responses. Compared with the traditional BP network, the GB-BP network improved the accuracy of predicting height error and surface roughness by 43.14% and 71.43%, respectively. The network can accurately predict the multi-objective characterization of the morphology and quality of multi-layer and multi-pass LDED metal printed parts.

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