2026,Volume 55, Issue 5

>2026 Phase Field Method-Integrated Computational Material Engineering

• Design and Phase-Field Simulation of Core-Shell Microstructure in TiNb Binary Alloy

  Chen Gongyu, Cheng Li, Liu Zihan, Zhang Gang, Zhu Jiaming

  2026,55(5):1129-1136 DOI: 10.12442/j.issn.1002-185X.20250225

  Abstract(16) HTML(51) PDF(1.92 M)( 37)

  Abstract:The core-shell structure in bulk TiNb binary alloy was designed and studied by phase-field simulations, where various core-shell structures were obtained by precise control of the initial and boundary conditions of the TiNb binary alloy system during spinodal decomposition, and then the formation mechanism of core-shell structure was revealed. In addition, the influences of initial temperature gradient, average temperature, and initial concentration distribution of the system on the core-shell structure were investigated. Results show that the initial concentration gradient is the key factor for forming the core-shell structure. Besides, larger initial temperature gradient and higher average temperature can promote the formation of core-shell structure, which can be stabilized by adjusting the initial concentration distribution of the Nb-rich region in TiNb binary alloy. As a theoretical basis, this research provides a novel and simple strategy for the preparation of TiNb-based alloys and other materials with peculiar core-shell structures and desirable mechanical and physical properties.

• Three-Dimensional Phase-Field Simulation of Grain Evolution in Physical Vapor Deposited Pure Ti Thin Film

  Zhang Tongdi, Ma Sa, Zhong Jing, Yang Shenglan, Zhang Lijun

  2026,55(5):1137-1145 DOI: 10.12442/j.issn.1002-185X.20250211

  Abstract(6) HTML(22) PDF(1.86 M)( 28)

  Abstract:Combining the phase-field method and the moving boundary method, a three-dimensional phase-field simulation was conducted for the growth and grain evolution of Ti films deposited by physical vapor deposition under different deposition rates and grain orientations. The evolution of grain morphology and grain orientation was also taken into consideration. Simulation results show that at lower deposition rates, the surface of the formed Ti film exhibits a distinct oriented texture structure. The surface roughness of the Ti film is positively correlated with the grain misorientation. Moreover, the surface roughness obtained from the simulation is in good agreement with the experiment results.

• Designing Optimal Temperature for Multi-directional Forging Process: A Phase-Field Crystal Study

  Song Zhuo, Li Huanqing, Tian Xiaolin, Kang Xiaolan, Hou Hua, Zhao Yuhong

  2026,55(5):1146-1156 DOI: 10.12442/j.issn.1002-185X.20250354

  Abstract(13) HTML(14) PDF(4.13 M)( 31)

  Abstract:Using multi-directional forging temperature as the independent variable and adopting the dual-mode phase field crystal model, the nucleation modes, reaction mechanisms, and interactions between grain boundaries and dislocations at different temperatures were investigated. Results show that a mapping relationship between process parameters and grain refinement/coarsening is established, and the optimal processing temperature coefficient is 0.23. Compared with the cases with processing temperature coefficient of 0.19, 0.20, 0.21, 0.25, and 0.27, the refinement effect increases by 256.0%, 146.0%, 113.0%, 6.7%, and 52.4%, respectively. Excessively high temperatures lead to grain coarsening due to dislocation annihilation, and the application of strain can reduce the actual melting point of materials. Even if the processing temperature does not exceed the theoretical melting point, remelting and crystallization may still occur, resulting in an overburning phenomenon that reduces internal defects and increases overall grain size. This research is of great significance for the actual forging process design.

• Multi-physics Study of Thermal History Effect on Non-equilibrium Solidification Microstructure of Ti-Nb Alloy During Dual-Track Selective Laser Melting

  Wu Dan, Wang Gang, Shi Rongpei

  2026,55(5):1157-1169 DOI: 10.12442/j.issn.1002-185X.20250053

  Abstract(11) HTML(17) PDF(3.81 M)( 33)

  Abstract:A multi-physics approach was used to quantify the effect of process parameters (laser power, scanning speed, hatch spacing, and scanning strategy) on the thermal history and corresponding microstructure evolution of Ti-25Nb (at%) alloy during the dual-track selective laser melting (SLM) process. Simulation results reveal that during the dual-track SLM process, increasing laser power results in greater thermal accumulation, leading to a molten pool of larger volume and coarser grains. Reducing scanning speed enhances remelting and promotes cellular growth at the top of molten pool, whereas faster scanning speed leads to rougher melt tracks and finer grains. Notably, hatch spacing significantly influences the molten pool dimensions and microstructures, and smaller hatch spacing promotes remelting. Furthermore, the orientations of grains in the second track during zigzag scanning differ markedly from those in the first track. More importantly, compared with those after the first track, both the temperature gradient and cooling rate at the boundaries of remelting molten pool are reduced after the second track scanning, resulting in slower interface velocity and significant change in solidification microstructure. This research provides a theoretical foundation for controlling non-equilibrium microstructure and offering novel insights into the optimization of SLM process parameters of titanium alloys.

• Effect of Gradient Layer Thickness on Anti-penetration Properties of 2024 Al/TC4 Laminated Composites

  Wang Kangan, Li Muxi, Hou Hua, Zhao Yuhong

  2026,55(5):1170-1183 DOI: 10.12442/j.issn.1002-185X.20240842

  Abstract(15) HTML(18) PDF(3.76 M)( 26)

  Abstract:A gradient structure was introduced into a metal laminated target plate, and the anti-penetration simulation of the gradient structure was compared with that of a uniform-layer-thickness target plate by finite element simulation. The analysis was verified by an impact experiment. Results show that the high-level thickness and appropriate percentage of Ti alloy at the upper side of the gradient structure provide greater impact resistance against the bullet, which increases the warhead breakage and enhances the anti-penetration performance. In addition, during the impact process, the stress is transmitted and reflected in the form of waves in each layer of the target plate, and the interaction between the compression and tension waves causes non-synergistic deformation of the target plate and leads to delamination. The gradient target plate takes penetration resistance a step further through the higher energy absorption rate and more consumption of the bullet kinetic energy. This research provides a theoretical basis for the application of gradient structures in metallic laminated armor.

• Phase-Field Simulation of Helium Bubble Formation in Pu-Ga Alloy

  La Yongxiao, Zhu Lipan, Liu Wenbo

  2026,55(5):1209-1215 DOI: 10.12442/j.issn.1002-185X.20250197

  Abstract(37) HTML(24) PDF(1.56 M)( 38)

  Abstract:Pu-Ga alloys are vital nuclear materials. However, the nucleation and growth of helium bubbles significantly affect their microstructural evolution and mechanical properties. In this work, a phase-field model was developed to simulate the formation and evolution of helium bubbles in Pu-Ga alloys during room-temperature aging. The model analyzed the morphological evolution of helium bubbles under different aging time and temperatures. According to phase-field simulation results, the variation curves of average diameter and number density of bubbles were obtained. The results show that at room temperature, bubble size and spatial distribution remain nearly unchanged, while the number density increases linearly. These simulation results align well with published experimental data. Further analysis indicates that aging temperature primarily affects growth kinetics of bubbles by influencing point defect mobility rate. In contrast, the exceptionally low diffusion coefficient at room temperature is the key factor leading to the unique evolution trends observed in bubble size and number density. This study provides a mesoscale theoretical model for accurately predicting the growth behavior of helium bubble in Pu-Ga alloys.

• Phase-Field Simulation of Influence of Stored Energy on Grain Growth in Alloys

  Li Xuexiong, Zhang Jinhu, Xu Haisheng, Ma Yingjie, Wang Hao, Wang Qingjiang, Xu Dongsheng

  2026,55(5):1216-1222 DOI: 10.12442/j.issn.1002-185X.20250235

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  Abstract:The optimized accelerated multi-phase field model was used to investigate the influence of magnitude and distribution of stored energy on the grain growth of alloy microstructures. The results show that the model successfully simulates and accelerates the microstructure evolution of a system with multiple order parameters. An increase in stored energy of alloy accelerates grain growth, leading to an increase in average grain size. During the early-to-mid stages of microstructure evolution, grains with high stored energy reduce the uniformity of local grain sizes. An increase in the non-uniformity of stored energy distribution can expedite the release process of stored energy in the early-to-mid stages of microstructure evolution, leading to a larger grain size. In the later stage, smaller and more uniform grain size is obtained. This research develops a polycrystalline geometric model for integrated microscale simulation of alloys, providing a theoretical basis for analyzing fine-scale parameter changes in grain size after high-temperature deformation.

• Phase-Field Simulation of Grain Growth During Final Stage of Sintering in Two-Phase Composite Fuels

  Zhai Jingjie, La Yongxiao, Liao Yuxuan, Wu Xuezhi, Shen Wenlong, Liu Wenbo

  2026,55(5):1223-1232 DOI: 10.12442/j.issn.1002-185X.20250214

  Abstract(9) HTML(14) PDF(2.30 M)( 30)

  Abstract:A numerical model based on phase-field method to simulate the grain growth during the final sintering stage of a two-phase UO₂-UN composite fuel was established, systematically investigating the grain evolution within the composite fuel system. Firstly, a simplified model of a void held between two grains was established to elucidate the interaction mechanism between grain boundary (GB) and voids. The results show that voids near GBs exhibit shrinkage dynamics and evolve into a ellipsoidal shape. Additionally, voids in contact with grains of high interfacial energy show significantly accelerated shrinkage rate. The triple interface angle in the system is determined by the ratio of the two-phase GB energy to the interface energy. Furthermore, a quantitative analysis was conducted on the grain growth process within the two-phase polycrystalline system. The investigation into the effect of phase volume fraction reveals that grain migration is significantly constrained by phase interface. As the volume fraction of the secondary phase increases, the increased phase interface density reduces the grain growth rate. Finally, the grain growth model for the two-phase polycrystalline system containing voids was developed to investigate the pinning effect induced by voids and to elucidate the growth kinetics at the final sintering stage. The results show that voids induce GB pinning, with the pinning strength positively correlated with void density. Non-uniform local void distribution can trigger abnormal grain growth. A three-dimensional void pinning analysis further shows that complex grain topology enhances the void pinning effect, resulting in more distinctive morphological features of abnormal grain growth in three-dimensional systems.

• Phase-Field Simulation Study on Phase Decomposition Behavior of U-Nb Alloys

  Cui Shushan, Wang Qinguo, Yin Jiaqing, Zou Dongli

  2026,55(5):1233-1241 DOI: 10.12442/j.issn.1002-185X.20250215

  Abstract(10) HTML(17) PDF(2.08 M)( 37)

  Abstract:The phase decomposition of U-Nb alloys exhibits significant microstructure changes with composition, aging temperature, and holding time. To study the physical mechanism of complex phase decompositions behavior of U-Nb alloys, systematic phase-field simulations were conducted. The results show that continuous and discontinuous precipitations may have the same thermodynamic condition. When the volume diffusion is inhibited and the interface diffusion plays a leading role, the phase decomposition is more inclined to discontinuous precipitation. It is speculated that the obvious difference of continuous precipitates between U-5Nb alloy and U-13Nb alloy is caused by different phase transformation mechanisms. U-5Nb alloy exhibits typical continuous precipitation, while U-13Nb alloy first undergoes miscibility gap decomposition within the γ phase, followed by the precipitate of α phase. The free energy relationship of γ phase in the middle Nb content range has an important influence on the occurrence of miscibility gap decomposition and the composition of the Nb-rich phase in the discontinuous precipitation product.

• Two-Sided Diffusion Quantitative Phase-Field Model for Isothermal Solidification of Multi-component Alloys

  Xu Haisheng, Zhang Jinhu, Li Xuexiong, Yang Liang, Liu Renci, Jia Qing, Liu Dong, Wang Hao, Xu Dongsheng, Wang Jincheng, Yang Rui

  2026,55(5):1242-1249 DOI: 10.12442/j.issn.1002-185X.20250233

  Abstract(9) HTML(14) PDF(1.81 M)( 33)

  Abstract:To achieve quantitative simulation of microstructure evolution during the solidification process of industrial alloys, this study extended one-sided diffusion quantitative phase-field model for isothermal solidification of multi-component alloys to two-sided diffusion one. The model was coupled with actual thermodynamic and kinetic data of the alloy, fully considering the interactions between different alloying elements. On the basis of eliminating the chemical potential jump at the interface, the anti-solute trapping coefficient A_i and phase-field mobility M in the two-sided diffusion quantitative phase-field model were redefined. Results show that taking Ti-45Al-8Nb (at%) ternary alloy as an example, 1D and 2D numerical simulations were conducted and compared with experimental results, validating the effectiveness of the established model in predicting the microstructure during solidification. The results provide theoretical support for further optimization of casting process and precise control of solidification microstructures.

• Simulation of α-Mg Dendrite Growth in AZ91 Magnesium Alloy Under Forced Convection Using Phase Field Method

  Feng Surui, Chen Weipeng, Pei Jiaqi, Sun Kaixin, Zhao Yuhong

  2026,55(5):1250-1258 DOI: 10.12442/j.issn.1002-185X.20250409

  Abstract(8) HTML(15) PDF(1.81 M)( 27)

  Abstract:During the solidification process of alloys, the flow of molten metal can significantly alter the thermodynamics of dendrite growth, thereby affecting the microstructure and mechanical properties of the components. This work established a phase field-lattice Boltzmann coupling model for the growth of α-Mg dendrites in Mg-9.0wt%Al-1.0wt%Zn alloy under forced convection, mainly studying the effect of melt convection on the growth of α-Mg dendrites. The results show that melt convection leads to asymmetric dendritic growth, with the upstream dendritic growth rate greater than the downstream one. This asymmetric morphology of dendrites becomes more pronounced with the increase in flow velocity. Through simulations of different flow velocity directions, it is found that the length of the dendrite arm is increased with the increase in angle between flow velocity direction and horizontal direction, while the thickness of the solute enrichment layer is decreased with the increase in angle. When the angle is 90°, the dendrite arm experiences the maximum shear force and deflection angle. In addition, the three-dimensional simulation results confirm that the asymmetric growth behavior of α-Mg dendrites under forced convection also exists in the three-dimensional simulation, manifested as a greater enrichment of solutes downstream and a concentration of solidification latent heat mainly upstream.

• Phase-Field Study of Al Addition Effects on Dendritic Growth and Solute Segregation During Non-Isothermal Solidification of Mg-3wt%Y-1wt%Zn Alloy

  Chen Yuanchao, Chen Weipeng, Pei Jiaqi, Feng Surui, Sun Kaixin, Zhao Yuhong

  2026,55(5):1259-1267 DOI: 10.12442/j.issn.1002-185X.20250408

  Abstract(9) HTML(16) PDF(2.25 M)( 25)

  Abstract:A multi-component quantitative phase-field model was developed to investigate the influence of the Al addition on the solidification behavior of Mg-3wt%Y-1wt%Zn alloy. The study focused on the growth kinetics, solute segregation, and controlling mechanism of secondary dendrite arm spacing (SDAS) of α-Mg dendrites. The results show that Al addition significantly suppresses the growth rate of α-Mg dendrites and reduces the growth rate of solid fraction. Moreover, Al effectively mitigates Zn microsegregation, substantially decreasing the segregation ratio, while having only a minor effect on Y segregation. Furthermore, Al promotes SDAS refinement by lowering the liquidus temperature, inhibiting solute diffusion, and reducing solid/liquid interfacial energy. Constitutional undercooling analysis indicates that higher Al content enhances solute accumulation, leading to increased undercooling, thereby altering dendritic nucleation and growth. This study provides valuable insights for optimizing the solidification microstructure and enhancing the mechanical properties and corrosion resistance of Mg-Y-Zn-Al alloys.

• Relationship Between Grain Orientation and Crack Propagation Revealed by Phase-Field Crystal Simulation

  Zhang Yunfan, Li Huanqing, Song Zhuo, Li Ning, Zhao Yuhong

  2026,55(5):1268-1278 DOI: 10.12442/j.issn.1002-185X.20250365

  Abstract(10) HTML(12) PDF(2.86 M)( 25)

  Abstract:The influence of different orientation angles on the microcrack propagation mechanism in nano twin crystal system under dynamic tensile conditions was investigated using the phase-field crystal method. The results show that under the same tensile conditions, the crack propagation mode, crack volume fraction, and crack propagation rate are related to the grain orientation. The difference in the crack propagation mechanism of the same orientation depends on the dislocation activity near the crack tip. A single dislocation located at the crack tip can easily lead to brittle expansion of the crack and accelerate the crack propagation rate. Dislocations in different directions at the crack tip may tangle together, which in turn hinders the crack propagation.

• Application and Prospects of Mechanically-Coupled Phase-Field Models in Aeronautical Materials

  Zhang Jinhu, Xu Haisheng, Wu Jiaqi, Li Xuexiong, Yang Liang, Wang Hao, Dong Limin, Xu Dongsheng, Yang Rui

  2026,55(5):1308-1316 DOI: 10.12442/j.issn.1002-185X.20250232

  Abstract(14) HTML(10) PDF(4.01 M)( 35)

  Abstract:With the rapid development of the aviation industry, superalloys and titanium-based alloys serve as core materials for aerospace engines and structural components, whose microstructure control and performance optimization are key factors to ensure equipment reliability. The mechanically-coupled phase-field model, as an effective tool for simulating microstructure evolution, bridges the gap among microscale mechanical principles, mesoscale microstructure simulation and macroscopic performance predictions. The model reveals the intrinsic connection between microstructure evolution and mechanical properties of materials in thermomechanical coupled field, providing theoretical support for the microstructure control and performance evaluation of aerospace materials. This paper systematically reviewed the research progress on mechanically-coupled phase-field models in the fields of typical aerospace materials, such as superalloys and titanium-based alloys. It outlined typical application cases of the model in investigating the mechanisms of solid-state phase transformation. This review encompassed applications of phase-field models from elastic and elastoplastic to defect-coupled formulations, addressing both γ′ phase precipitation and rafting in superalloys, as well as the evolution of precipitate phases in titanium-based alloys. Furthermore, it discussed the challenges in current research and provided an outlook on the future prospects of the mechanically-coupled phase-field model in aerospace material research. Lastly, it highlighted the key issues of this type of phase-field model and its future development directions.

• Application of Phase Field Simulation in Reliability of Electronic Packaging

  Dong Shuhan, Wu Peng, Zhou Songchao, Li Haozhe, Sun Gehui, Lin Pengrong, Feng Jiayun, Wang Shang, Tian Yanhong

  2026,55(5):1317-1333 DOI: 10.12442/j.issn.1002-185X.20250226

  Abstract(10) HTML(10) PDF(3.21 M)( 31)

  Abstract:With the rapid advancement of electronic devices towards miniaturization, high integration, and multifunctionality, the complexity of chip packaging has increased significantly. As packaging density continues to rise and solder joint size decreases, the operating conditions of electronic components in service become increasingly demanding. Consequently, the reliability of micro-interconnect solder joints has become a critical concern, with solder joint failure emerging as one of the key bottlenecks hindering the further development of electronic packaging techniques. This paper focuses on the failure behavior of micro-interconnect solder joints and reviews several common reliability issues in electronic packaging. Based on the selection of different phase-field variables, several typical phase-field modeling approaches are summarized. Furthermore, the paper analyzes the application and current progress of phase-field methods in simulating several representative failure modes, such as electromigration, through-silicon vias (TSVs), and interfacial intermetallic compound (IMC) growth. Finally, the potential of phase-field modeling in studying micro-scale failure mechanisms is discussed, along with its future development trends in multi-physics coupling, data-driven modeling, and engineering applications. This work aims to provide systematic references and methodological support for both theoretical analysis and practical engineering studies on the failure behavior of micro-interconnect solder joints.

• Research Status and Prospects of Solidification Microstructure Selection Maps in Metal Additive Manufacturing Processes

  Lai Wenfu, Liu Jia, Zhang Lijun

  2026,55(5):1334-1347 DOI: 10.12442/j.issn.1002-185X.20250234

  Abstract(12) HTML(14) PDF(4.42 M)( 34)

  Abstract:Metal additive manufacturing, characterized by its point-by-point and layer-by-layer forming process, enables the efficient and precise fabrication of complex structural components that are difficult to produce with traditional manufacturing techniques. However, the metal additive manufacturing process involves large temperature gradients and rapid cooling rates, constituting a highly non-equilibrium process that may lead to crack formation within the solidified microstructure, thereby influencing the mechanical properties of the material. Consequently, the control of solidification microstructure during metal additive manufacturing is pivotal for designing materials with superior mechanical properties. The solidification microstructure selection map serves as a tool that establishes a mapping relationship between composition/process parameters (used as both horizontal and vertical axes) and solidification microstructure, enabling the prediction and regulation of solidification microstructures in metal additive manufacturing processes. This review provided a comprehensive summary of the current types of solidification microstructure selection maps, outlined their construction methodologies, and summarized the applications of various solidification microstructure selection maps in metal additive manufacturing processes for recent years. Lastly, this review offered insights into the prospects of solidification microstructure selection maps in terms of novel types, innovative construction approaches, and potential application values.

• Research Progress on Pre-treatment Techniques of Casting Process Simulation Software

  Cui Yuwei, Pan Yue, Duan Zhiqiang, Liu Bin, Pei Xiaolong, Chen Liwen, Hou Hua, Zhao Yuhong

  2026,55(5):1348-1362 DOI: 10.12442/j.issn.1002-185X.20240849

  Abstract(6) HTML(14) PDF(2.26 M)( 24)

  Abstract:The pre-processing module is a core component of casting numerical simulation software, directly influencing the accuracy and efficiency of simulations. This paper presented a comprehensive review of pre-processing techniques in casting simulation, with a specific focus on geometric modeling, parameter configuration, and the pivotal mesh generation techniques. The principles and evolutionary history of hexahedral, tetrahedral, and hybrid meshing methods were elaborated. Furthermore, the strengths and limitations of various algorithms in handling complex castings were analyzed. Finally, the paper identified key challenges currently facing pre-processing modules and outlined future development trends.

>Materials Science

• Effect of Element Ti on Microstructure, Properties, and Thermal Stability of NbTaMoWTi_x Refractory High-Entropy Alloys

  Ou Pengcheng, Wan Qiang, Jiang Hui, Sha Minghong, Sun Jiabin, Ai Xingang, Li Shengli, Huang Tiandang

  2026,55(5):1184-1190 DOI: 10.12442/j.issn.1002-185X.20250034

  Abstract(10) HTML(20) PDF(2.44 M)( 34)

  Abstract:The effect of element Ti on the microstructures and mechanical properties of as-cast and annealed NbTaMoWTi_x (x=0, 1, 1.5, 2) refractory high-entropy alloys (RHEAs) was investigated. Results show that after Ti addition, the as-cast alloys maintain their original single body-centered cubic (bcc) structure. As for the mechanical properties, compared with those without Ti addition, the strength and ductility of NbTaMoWTi_x alloys increase by 93% and 215%, respectively. Furthermore, the NbTaMoWTi_x alloys exhibit outstanding thermal stability. After annealing at 1400 °C, they still maintain the single bcc structure, and their mechanical properties are even slightly improved. However, annealing leads to a significant deterioration in the mechanical properties of high-Ti-content alloys (NbTaMoWTi_1.5 and NbTaMoWTi₂), owing to the formation of Ti-rich acicular phases.

• Low-Cycle Fatigue Behavior of Ultrafine-Grained Pure Titanium

  Liu Xiaoyan, Wang Zixuan, Yang Xirong, Luo Lei, Wang Jingzhong

  2026,55(5):1191-1198 DOI: 10.12442/j.issn.1002-185X.20250036

  Abstract(12) HTML(13) PDF(4.86 M)( 25)

  Abstract:Ultrafine-grained (UFG) pure titanium was produced by equal channel angular pressing for 4 passes, followed by rotatory swaging at room temperature. The strain-controlled low-cycle fatigue tests of UFG and coarse-grained (CG) pure titanium were conducted by Instron electro-hydraulic servo fatigue testing machine in the strain amplitude range of 0.5%–1.1% at room temperature. Transmission electron microscope (TEM) and scanning electron microscope were used to investigate the microstructure and fracture surface of UFG pure titanium after fatigue tests. Results show that UFG pure titanium exhibits a longer low-cycle fatigue life, compared with the CG pure titanium. For example, at a total strain amplitude of 0.5%, UFG and CG pure titanium has fatigue life of 10 850 and 4820 cycles, respectively. Significant cyclic softening occurs in UFG pure titanium, except in the case of a total strain amplitude of 0.5%. Hysteresis loop area is increased rapidly with the increase in strain amplitude. The fracture surface shows that the fatigue crack is initiated from the specimen surface. A series of fatigue striations and many microcracks exist in the propagation region. With the increase in strain amplitude, the predominant failure mode is transformed from ductile failure into quasi-cleavage failure. Dislocation slip is the main plastic deformation mechanism of UFG pure titanium during low-cycle fatigue deformation.

• Real-Time Tracking of Tensile Deformation Behavior in GH4169 Under Tensile Stress Based on DIC and EBSD

  Zhang Limin, Zhang Hongju, Xia Wen, Yu Limin, Cao Dongdong, Jia Rongguang

  2026,55(5):1199-1208 DOI: 10.12442/j.issn.1002-185X.20250350

  Abstract(12) HTML(13) PDF(4.01 M)( 24)

  Abstract:The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation (DIC) and electron backscatter diffraction (EBSD) in-situ characterization techniques. Results show that in the field of grain deflection dynamics, through quantitative analysis using the independently developed M-DIC software, during uniaxial tension with significant bidirectional rotation along the tensile axis and the stress level of 1100 MPa, oscillatory rotation of ±0.6° can be obtained, and microvoids are generated at the grain boundaries with 45° to the stress axis. EBSD crystallographic analysis demonstrates the load-dependent slip system evolution: in the initial stage, the soft-oriented systems with high Schmid factor (>0.4) is activated and then transformed into hard-oriented systems during cross-slip, generating parallel slip bands and dislocation pile-ups at grain boundaries. During the uniaxial tensile process, the characteristic of strain energy accumulation is observed, which follows a two-stage accumulation pattern: initial grain boundary localization (Stage I) and intragranular propagation (Stage II). Ultimately, the intergranular cracks are initiated at triple junctions, and the twin boundaries exhibit superior mechanical stability compared with the large-angle grain boundaries. Deformation texture characteristics indicate the copper-type components, including C{112}<11>, S{123}<63>, and B{110}<10>. The complete deformation sequence is as follows: cross-slip of soft-oriented slip systems→initiation of dislocation slip→strain partitioning through grain rotation→intergranular stress concentration→damage dominated by boundary cracking. The cross-scale deformation mechanism revealed in this study provides critical guidance for the crystal boundary engineering to optimize nickel-based superalloys.

• Kinetic Behavior of Supercooled Liquid of Zr₆₁Ti₂Cu₂₅Al₁₂ Amorphous Alloy: by Flash Differential Scanning Calorimetry

  Li Xiaocheng, Kou Shengzhong, Chen Yongxuan, Li Lin, Na Huikang, Li Chunling

  2026,55(5):1279-1285 DOI: 10.12442/j.issn.1002-185X.20230404

  Abstract(10) HTML(7) PDF(1.79 M)( 37)

  Abstract:Based on the classical nucleation theory, a time-temperature-transformation (TTT) curve of Zr₆₁Ti₂Cu₂₅Al₁₂ alloy was constructed, and its critical cooling rate R_c was estimated and modified as about 63 K/s. The reliability of this estimation was evaluated using the glass-forming ability criteria, and the dominant roles of nucleation rate I and growth rate U on the crystallization mechanism in different supercooled liquid regions were explained. Combining flash differential scanning calorimetry with conventional thermal analysis, a heating rate range spanning six orders of magnitude (10^-2–10⁴ K/s) was achieved for the Zr₆₁Ti₂Cu₂₅Al₁₂ amorphous alloy, demonstrating the heating-rate dependence of kinetic behavior of supercooled liquid over an ultra-wide range. Results show that firstly, the dependence of heating rate on characteristic temperatures follows the Vogel-Fulcher-Tammann equation. Secondly, the small change in fragility coefficient (m=30–41) means that its supercooled liquid structure changes relatively smoothly with temperature, exhibiting “strong” liquid behavior to a certain extent, making the alloy have a certain glass-forming ability. This study provides technical guidance and theoretical basis for the preparation of Zr₆₁Ti₂Cu₂₅Al₁₂ amorphous alloy, especially for the plastic forming in the supercooled liquid region and the formulation of heat treatment process.

• Research on Creep Fracture Behavior of DZ411 Alloy at 950 °C/190 MPa

  Li Yan, Huang Yao, Yu Shan, Wang Yuqi, Shang Jiaxin, Zhao Chengzhi, Zhang Hexin

  2026,55(5):1286-1291 DOI: 10.12442/j.issn.1002-185X.20240797

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  Abstract:The creep behavior of the DZ411 alloy at 950 ℃ and 190 MPa was investigated using high-resolution transmission electron microscopy and scanning electron microscopy. The relationship between the deformation mechanism of the γ′ phase and the strain rate during creep was elucidated. With various creep durations, the alloy forms a raft structure due to the directional diffusion of elements. Because the length of the rafted γ′ phase is significantly extended, the impeding effect on dislocations is greatly increased. Consequently, in the early stage of creep and before the rafting of the γ′ phase, the alloy exhibits a higher strain rate, with a total strain variation of 0.31% and a strain rate of 2.78×10^–7 s^–1. As the rafting process of the γ′ phase progresses, the impeding effect on dislocations also increases, causing the alloy to enter a steady-state creep phase. In this phase, the strain rate significantly decreases, with a total strain variation of 2.35% and a strain rate of 2.17×10^–8 s^–1. However, when the stress in the alloy accumulates to a certain extent, dislocations will enter the γ′ phase through a climbing mechanism. A large number of dislocations cutting into the γ′ phase adversely affect the continuity of the raft structure, reducing the effective length of the γ′ phase, significantly weakening the impeding effect of the dislocations, and causing the alloy to enter an unstable state. This accelerates the creep process and ultimately leads to the fracture of the alloy. The total strain variation in this stage is 17.05%, with a strain rate of 2.22×10^–7 s^–1.

• Nanocrystallization on Surface Layer of Tungsten Using Pressure-Assisted Heat Treatment Process

  Zhang Pengfei, He Huanju, Zhang Zhansheng, Wang Biao, Qu Jingjing, Lin Tiesong, Yang Zhihua

  2026,55(5):1292-1298 DOI: 10.12442/j.issn.1002-185X.20240713

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  Abstract:To further improve the service life of tungsten (W) workpieces under harsh working conditions such as high-energy irradiation and arc erosion, it is necessary to carry out nanocrystallization treatment on the W surface to further improve the fatigue resistance and radiation resistance of surface materials. However, due to the high melting point and high hardness of W, it is very difficult for the surface material of W to undergo plastic deformation or local melting. This research used pure W plate as raw material. The W plate was applied with a pressure of 10 MPa, and then it was heated to 900 ℃ in a vacuum environment and kept at this target temperature for 3 h. The surface of W plate was treated by the pressure-assisted heat treatment process. The results show that for the treated W plate, a nanocrystalline layer with a thickness of 2–4 μm is formed on its surface, and the nanocrystal layer exhibits a uniform thickness. The nanocrystals are equiaxed in shape, with an average grain size generally less than 300 nm. However, the microstructure inside W plate still keeps coarse grains. The nanocrystalline layer is firmly bonded to the internal coarse grains, without any obvious interfaces. This work is potentially to explore a more efficient and convenient technical path for the surface nanocrystallization of refractory metals such as W, which has important theoretical significance and practical application value.

• Laser Welding Process of Titanium/Steel Dissimilar Metals Assisted by Laser Cladding V Transition Layer and Their Properties

  Li Yang, Lu Lili, Xu Muzhong, Gai Xin, Du Hang, Ding Tao, Le Wangyun, Xing Li, Yan Chengwen, Ou Lena, Gong Ya, Li Quan

  2026,55(5):1299-1307 DOI: 10.12442/j.issn.1002-185X.20250128

  Abstract(18) HTML(19) PDF(1.83 M)( 29)

  Abstract:Titanium/steel dissimilar metal structural components have great application prospects in multiple fields. In this work, the method of laser cladding vanadium (V) transition layer was adopted to assist the laser butt welding of Ti-4Al-2V titanium alloy and 06Cr18Ni11Ti stainless steel, and titanium/steel dissimilar metal joints with excellent microstructure and properties were obtained. Using high-purity vanadium (V) powder as the transition metal material, a certain thickness of V transition layer was prepared on the 4 mm-thick end face of Ti-4Al-2V titanium alloy by laser cladding equipment through a multi-layer and multi-pass cladding process, and the chemical composition, microstructure morphology and residual stress in the transition layer were analyzed. Subsequently, the V cladding sample was subjected to laser butt welding with 06Cr18Ni11Ti stainless steel to characterize the macroscopic morphology, microstructure, mechanical properties (tensile strength and impact toughness at high and room temperatures), fracture morphology and joint hardness of the titanium alloy+V transition layer+laser weld seam+stainless steel welded joint. The results show that during the laser cladding of V transition layer on titanium alloy, when the thickness of V layer reaches≥6.8 mm, the V content near the surface of the cladding metal is approximately 98wt%, and the Ti content decreases to 0.18wt%–0.22wt%. The average tensile strength at room temperature of the above-mentioned titanium/steel welded joints is 537.3 MPa, and the average tensile strength at high temperature (350 ℃) is 426.3 MPa. Moreover, the tensile specimen at room temperature fractures on the V cladding layer. The average impact toughness is 38.2 J/cm² (at the center of the weld seam), 102.6 J/cm² (in the heat affected zone, on the side adjacent to the V cladding layer), and 167.6 J/cm² (in the heat affected zone, on the side adjacent to the stainless steel). SEM analysis was conducted on the fracture surfaces of the tensile specimens. The fracture morphology shows that dimples account for the main part, and in some local areas, there are mixed fracture characteristics of dimples+cleavage or quasi-cleavage, indicating that both ductile and brittle fractures exist simultaneously, with ductile fracture being the main type.

>Reviews

• Research Progress on Radial Forging for Superalloy

  Li Shu, Zhong Jia, Yao Kaijun, Jiang He, Yao Zhihao, Dong Jianxin

  2026,55(5):1363-1373 DOI: 10.12442/j.issn.1002-185X.20240791

  Abstract(5) HTML(15) PDF(1.64 M)( 26)

  Abstract:Superalloys, serving as the critical materials for hot-end components like turbine blades, combustion chambers, and turbine disks, are widely used in aviation, aerospace, and energy sectors due to their excellent performance in high-temperature environments. However, controlling the microstructure of superalloys remains a significant challenge in actual production. Radial forging, with its high efficiency, high material utilization, and significant improvement of the microstructure of forgings, shows great potential in the production of superalloy materials. Through multiple hammers and high-frequency forging, radial forging achieves uniform deformation of the billets, enhancing the mechanical properties and internal density of the forgings. This paper systematically elaborates on the driving principles of radial forging equipment and the influence of key process parameters on the production process. It analyzes the microstructure evolution mechanism and grain growth behavior of superalloys under multi-pass high-frequency forging, compares the applicability of different forging penetration models, and summarizes the current research status of stress-strain constitutive models and microstructure evolution models in finite element simulation. This review also points out that high-precision multi-physics coupled simulation and intelligent process design are the core directions for future development.

• Research Progress on Irradiation Damage Behavior of Molybdenum-Rhenium Alloys for Nuclear Reactors

  Chang Tian, Lin Xiaohui, Zhang Weiwei, Xin Tian, Xue Jianrong, Liang Jing, Gao Xuanqiao, Zhang Wen

  2026,55(5):1374-1384 DOI: 10.12442/j.issn.1002-185X.20250279

  Abstract(18) HTML(24) PDF(1.66 M)( 39)

  Abstract:The structural materials of space nuclear reactors need to withstand extreme service environments such as high temperature and high-flux neutron irradiation, and their performance greatly affects the safety and economy of reactor operation. This paper focuses on the irradiation damage behavior of Mo-Re alloys used in space nuclear reactors, reviews irradiation damage effects, microstructure evolution caused by irradiation, and degradation of service performance. It provides a theoretical basis for the microstructure optimization, performance prediction, and service life evaluation of Mo-Re alloys as reactor materials.

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(135) PDF(1.26 M)(90)

  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(33) PDF(1.30 M)(62)

  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(46) PDF(1.45 M)(60)

  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(96) PDF(1.23 M)(62)

  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(45) PDF(2.15 M)(57)

  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(45) PDF(1.64 M)(67)

  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.

• 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(79) PDF(1.52 M)(98)

  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(70) PDF(1.79 M)(64)

  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%.

• 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(53) PDF(1.73 M)(61)

  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(41) PDF(1.22 M)(66)

  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(71) PDF(1.65 M)(75)

  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(74) PDF(1.00 M)(62)

  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(65) PDF(1.67 M)(88)

  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.

• 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(55) PDF(1.18 M)(65)

  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(57) PDF(2.77 M)(74)

  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.

• 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(44) PDF(1.04 M)(68)

  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.

• Study on Microstructure and Friction and Wear Properties of Pre-formed Films of Zr-2.5Nb Alloy Prepared by Different Processes

  Luoqinwen, zhangpeng, yuqiang, zhaoguannan, hulijuan, xushitong, yaomeiyi, zhoubangxin

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250407

  Abstract(73) PDF(1.11 M)(34)

  Abstract:Micro-motion wear is one of the primary factors limiting the service life of pressure tubes used in heavy-water reactors. To enhance the operational reliability of Zr-2.5Nb pressure tubes for heavy-water reactors, this study prepared a pre-formed film approximately 1 μm thick on the surface of Zr-2.5Nb alloy using three different processes and investigated the relationship between its mechanical properties and microstructure. The three pre-oxidation treatment processes were carried out for 24 hours at 400 °C: one in deoxidized superheated steam at 10.3 MPa; one in superheated steam with 300 μg/kg of dissolved oxygen; and one in low-pressure steam at 2 MPa.The results indicate that the Zr-2.5Nb alloy consists of α-Zr and β-Zr phases, with both α-Zr and β-Zr exhibiting elongated morphologies, and β-Zr continuously distributed at the α-Zr grain boundaries.The microstructures of the films formed under different pre-oxidation conditions exhibit differences: the pre-formed film under deoxidized conditions contains relatively more microcracks, with shorter and more randomly arranged columnar grains; the pre-formed film under dissolved oxygen conditions is the most dense with the fewest defects, while the pre-formed film under low-pressure conditions has the greatest thickness but relatively more pores and cracks.Compared with the original alloy, the pre-formed film increased the nano-hardness of the alloy by 50%–180%, improved the hardness-to-modulus ratio (H/E) by approximately 56%–81%, and reduced the wear rate by 31%–44%. The pre-formed film significantly enhanced the surface hardness and wear resistance of the alloy, transforming the wear mechanism from severe abrasive wear to mild adhesive wear.Among these, the pre-formed film produced under dissolved oxygen conditions is the most dense and exhibits the most pronounced hardness enhancement. This is because the strengthening effect of the pre-formed film is closely related to its microstructure. A dense and intact oxide film not only has higher hardness but also adheres more firmly to the metal substrate, making it less prone to peeling or cracking under localized stress.

• High-Temperature Wear Behavior of GNP/SiC/Al Composites and its Comparison with Gray Cast Iron

  Bi Sheng, Hu Kaiqi, Zhou Bo, Xie Longfei, Zhu Jie, Zhang Haihong, An Zhen

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250410

  Abstract(33) PDF(1.92 M)(35)

  Abstract:SiC and graphene nano-platelet (GNP) hybrid reinforced aluminum matrix (GNP/SiC/Al) composites were fabricated via high-energy ball milling combined with powder metallurgy. The microstructure, mechanical properties, and wear performance of the composites were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), universal tensile testing machines, and tribometers, with comparative analysis against gray cast iron (HT250). Results indicate uniform dispersion of SiC and GNP within the matrix. The composites exhibited the tensile strengths of 287 MPa and 101 MPa at room-temperature and 350°C, respectively. During room-temperature wear tests, the composites demonstrated inferior wear resistance to HT250, with both materials exhibiting adhesive and abrasive wear mechanisms. Under high-temperature wear conditions, the composites showed significantly superior wear resistance to HT250. While HT250 exhibited adhesive and abrasive wear mechanisms, the composites primarily underwent adhesive wear. The exceptional high-temperature wear resistance of GNP/SiC/Al composites is attributed to three primary mechanisms: (1) the high-temperature pinning effect of SiC and GNP, (2) the self-lubricating properties of GNP, and (3) the formation of mechanically mixed layers during wear.

• Research Progress of additive manufacturing technologies for metallic porous materials applications

  Yang Kun, Shen Lei, Zhao Shaoyang, Xu Chenyang, Xu Zhongguo

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250417

  Abstract(35) PDF(1.28 M)(29)

  Abstract:Porous metallic materials are a class of materials characterized by their structurally and functionally integrated features, with a well-defined pore structure being their most notable attribute. This porous structure enables them to exhibit dual characteristics of both metallic and porous materials, making them widely applicable in fields such as nuclear industry, petrochemical engineering, and aerospace. Additive manufacturing technology allows for the integrated fabrication of complex porous metallic structures, offering advantages such as high material utilization and precise control over pore structure. This paper reviews the current development of additive manufacturing technologies for porous metallic materials, with a focus on analyzing the pore formation mechanisms and performance characteristics of additively manufactured porous metallic materials. It also summarizes their application progress in industries such as healthcare and tooling, discusses the integration of artificial intelligence in metallic additive manufacturing, and provides an outlook on the future development of this technology.

• Microstructure and Mechanical Properties of High-speed Extruded Mg-8Al-0.4Zn-0.9Ca-0.2Gd-0.2Mn Alloy

  Meng Shuaiju, Wang Menglu, Chen Jianfei, Zhang Jianjun, Yang Guirong, Bi Guangli

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250420

  Abstract(36) PDF(1.42 M)(31)

  Abstract:Improving the extrusion speed of Mg alloys is crucial for expanding their applications. Here we show a novel heavily alloyed Mg-8Al-0.4Zn-0.9Ca-0.2Gd-0.2Mn (AZXVM80100, wt.%) alloy having outstanding extrudability and good mechanical performance. It can be extruded at a die exit speed of 32.4 m/min without any hot cracks. The excellent extrudability is mainly attributed to the dominant presence of Al2Ca, Al2Gd and Al8Mn5 phases with high thermal stability, which did not melt despite the substantial amount of deformation heat generated during the high-speed (32.4 m/min) extrusion, avoidiing hot cracking. Meanwhile, these thermally stable Al2Ca, Al2Gd, and Al8Mn5 phases exerted a remarkable refining effect on the recrystallized grains. Besides, the as-extruded AZXVM80100 alloy displays a fully dynamic recrystallized microstructure. It has a typical basal texture and fine grains with an average grain size of 8.6±1.7 μm. Owing to the significant grain boundary strengthening, the as-extruded AZXVM80100 alloy demonstrates a high tensile yield strength of 257.4±4.1 MPa. Furthermore, the as-extruded AZXVM80100 alloy also exhibits a high elongation of 14.9±0.8%, which is dominantly coordinated by dislocation slip. The newly developed high speed extrudable AZXVM80100 alloy, containing large amounts of cheap elements (Al, Zn, Ca, Mn) and trace amounts of rare earth (Gd), has great potential in manufacturing extrusion profiles because of its good strength-ductility synergy.

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