2026,Volume 55, Issue 6

>ARTICLE

• Enhanced Wear Resistance of ULDLC Duplex Stainless Steel Coating via Laser Remelting

  Li Congwei, Zhu Jialei, Zeng Caiyou, Deng Caiyan, Cong Baoqiang, Cui Lei, Jiao Xiangdong

  2026,55(6):1385-1392 DOI:

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  Abstract:Underwater local dry laser cladding (ULDLC) is a key technique for in-situ repair of nuclear power equipment. In this study, an underwater laser remelting technique was proposed to further enhance the wear resistance of duplex stainless steel (DSS) coatings prepared by ULDLC. The effects of laser remelting heat input on the microstructure and wear resistance of DSS coating prepared by ULDLC were investigated. Results indicate that the microstructure of DSS coatings consists of Widmanst?tten austenite (WA), intergranular austenite (IGA), grain boundary austenite, secondary austenite (γ₂), and ferrite. With the increase in laser remelting heat input, the content of IGA and WA gradually decreases, while the ferrite content increases. After laser remelting, γ₂ is eliminated and the grain morphology of ferrite is transformed from flaky to equiaxed. Under optimal laser remelting parameters (a laser power of 3 kW, a laser spot diameter of 6 mm, and a laser scanning speed of 10 mm/s), the microhardness of remelted zone is 318.7 HV, which is increased by 25.7 HV, the friction coefficient decreases by 32%, and the wear volume is reduced by 55%. The significantly improved wear resistance is attributed to the synergistic effects of surface oxide-layer formation and ferrite grain refinement.

• Effect of Dendrite Refinement on Microstructure and Stress Rupture Properties of Third-Generation Nickel-Based Single-Crystal Superalloys

  Zhao Yunxing, Wang Di, Ma Dexin, Wei Jianhui, Cheng Bowen, Sun Hongyuan, Xu Weitai, Huang Zaiwang

  2026,55(6):1393-1399 DOI:

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  Abstract:A third-generation single-crystal superalloy WZ30 was used to prepare single-crystal samples with varying dendrite spacings under different processing techniques. The microstructure and stress rupture properties were studied and compared. The results show that, by improving the thermal-insulation effect between heating zone and cooling zone of the directional solidification furnace, the average primary dendrite spacing of the as-cast sample is reduced from 415 μm to 251 μm, leading to a noticeable refinement of dendrite and eutectic structure. At the same time, dendrite refinement can simultaneously decrease the volume ratio of casting porosity from 2.29% to 0.21%. Additionally, the γ′ phase in both the dendritic and inter-dendritic regions undergoes refinement, with a more uniform size distribution and a more regular shape. After the subsequent solid solution and aging treatments, the smaller γ′ precipitates with higher cubic degree are obtained in samples after dendrite refinement, whose service life at 980 °C/ 280 MPa is improved by 13.8%.

• Constitutive Model and Application of 2060 Aluminum-Lithium Alloy in Hot Stamping Process

  Yang Xiaoming, Liu Shengqiang, Huang Xiaomin, Ji Hongchao, Wang Baoyu

  2026,55(6):1400-1408 DOI:

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  Abstract:2060 alloy, as the third generation aluminum-lithium (Al-Li) alloy, has lighter mass than traditional aluminum alloys and superior mechanical properties compared with previous generations of Al-Li alloy. The hot deformation behavior of 2060 Al-Li alloy sheets were investigated by hot tensile tests and model analysis. The fracture morphology was observed by scanning electron microscope. Then, the constitutive model coupled with the macroscopic mechanical behavior and the microstructure evolution was established. Finally, the established constitutive model was embedded in the finite element simulation software to analyze the deformation process of 2060 Al-Li alloy. The results show that the peak stress decreases with the increase in temperature and the decrease in strain rate. The deformation temperature has a significant impact on the anisotropy of the 2060 Al-Li alloy. It can be considered that the anisotropy can be eliminated at 400 °C or higher temperatures. It is found that the fracture process of 2060 Al-Li alloy conforms to typical ductile fracture laws. The presence of ridge improves the sheet deformation at elevated temperature. The constitutive model can predict the change of the true stress-true strain curves and the microstructure evolution accurately. The simulation results have good agreement with the experimental tests under hot stamping conditions.

• Effect of Heat Treatment Temperature on Microstructure and Corrosion Resistance of TA1/304 Composite Plates

  Li Xijie, Li Zhipeng, Liu Jianglin, Zhao Linchao, Tang Yuping, Liang Jianguo

  2026,55(6):1409-1418 DOI:

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  Abstract:The corrosion resistance and corrosion mechanism of TA1/304 composite plates after heat treatment at different temperatures were studied by simulating electrochemical experiments in artificial seawater (3.5wt% NaCl solution). The interfacial diffusion and microstructure evolution were studied. The results show that the diffusion range of interfacial elements and the thickness of the diffusion layer change with the heating temperatures. Because of its special structure and composition, the TA1/304 composite plate shows excellent corrosion resistance in Cl^--containing corrosive media, and its corrosion resistance is significantly better than that of ordinary steel plates. Meanwhile, it is found that the heat treatment process of the composite plate has a significant impact on its corrosion resistance. After annealing at 600 °C, the corrosion resistance of the composite plate is improved, and corrosion properties of rolled surface is much greater than that of the cross-section. This research achievement provides important theoretical basis and technical support for the further application of TA1/304 composite plates in fields with strict corrosion resistance requirements, such as chemical engineering and marine engineering.

• Effect of Solid Solution Treatment on Mechanical Proper-ties of Aero-Engine Turbine Cases

  Shi Wenxin, Xu Huanxiao, Xie Zhenqiang, Tang Lei, Yang Xi, Cao Yuhan, Cheng Taotao

  2026,55(6):1419-1428 DOI:

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  Abstract:Waspaloy alloy is widely used in aerospace applications, particularly in gas turbines operating under extreme service conditions. The effects of solid solution duration and temperature on the microstructure and mechanical properties of a Waspaloy low-pressure turbine (LPT) case in in-service aero-engines were investigated via on-site metallographic replication techniques and laboratory verification tests. The results show that excessive solid solution treatment (1010 °C/11 h) has no adverse impact on the microstructure or grain size of the LPT cases. The alloy exhibits low sensitivity to solid solution duration. As the solid solution duration is prolonged from 4 h to 20 h, the grain size remains unchanged, and the grain morphology remains essentially consistent. Only a gradual decrease in the number of twins in the microstructure and a gradual increase in proportion of fine strengthening phases are observed. In contrast, the alloy is highly sensitive to solid solution temperature. When the solid solution temperature increases from 1010 °C to 1040 and 1070 °C, the grain size increases from Grade 7.5 to Grade 6.5 and to grade 3.0, respectively. Simultaneously, the primary strengthening phases within austenite grains are fully replaced by secondary ones. Additionally, M₂₃C₆ carbides at γ phase grain boundaries transition from isolated island-like morphologies (at low temperature) to elongated strip-like morphologies (at high temperature). Simultaneously, both the quantity and size of the intragranular MC carbides significantly increase. The microhardness and mechanical properties of the alloy are predominantly governed by the scale of strengthening phases and grain size. With the prolongation of solid solution duration, the microhardness, tensile strength, and yield strength progressively increase. However, as the solid solution temperature rises, these properties increase first and then decrease.

• Effect of Laser Shock Peening on Creep Aging Behavior and Springback of 2195 Al-Li Alloy

  Zhang Liwen, Bian Tianjun, Gong Xiaotao, Cui Yingguo, Song Jiping

  2026,55(6):1429-1436 DOI:

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  Abstract:Hardness testing, microstructural characterization, and creep aging forming experiments were conducted to investigate the impact of laser shock peening (LSP) treatment on the creep aging behavior of 2195 Al-Li alloy and to evaluate its effect on the springback of single-curved components formed through creep aging. The results indicate that, compared to the creep-aged alloy without LSP treatment, the hardness of the creep-aged alloy with LSP treatment is increased by approximately 22%. Grain size is notably reduced from the surface to the middle layer of the plate, with the greatest decrement in surface layer (49 μm) and the least in the middle layer (4 μm). The T1 precipitate phase in the creep-aged alloy with LSP treatment exhibits a denser distribution, greater quantity, and finer grain size, compared with that without LSP treatment. Furthermore, the springback ratio of creep-aged sheets subjected to LSP treatment is significantly lower than that of untreated sheets, decreasing by about 37.6%. The enhancement in hardness is attributed to fine grain strengthening and substantial precipitation strengthening induced by LSP. The reduction in springback is ascribed to the increased creep deformation resulting from the combined effect of the compressive stress on the concave surface of the plate during bending and the residual compressive stress generated by LSP treatment.

• Study on Flow Stress Constitutive Relationship of GH738 Superalloy Based on Machine Learning

  Wang Shuangjian, Wang Kelu, Lu Cuiyuan, Luo Baile, Xu Bing, Zhou Shixin, Wang Panzhi

  2026,55(6):1437-1450 DOI:

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  Abstract:Hot compression experiments were conducted on GH738 superalloy using Gleeble 3500 thermal simulation machine at deformation temperature of 980–1100 °C and strain rate of 0.001–0.1 s^-1 to study the flow stress behavior of the alloy. Three machine learning algorithms, namely random forest (RF), support vector machine (SVM), and genetic algorithm-back propagation (GA-BP) neural networks, were employed to establish constitutive relationship models for the flow stress behavior of GH738 superalloy. Subsequently, these models were compared and analyzed in terms of their predictive accuracy. The results indicate that the flow stress of GH738 superalloy decreases with the increase in deformation temperature and the decrease in strain rate. The correlation coefficients for the RF, SVM, and GA-BP constitutive relationship models are determined as 0.921, 0.998, and 0.999, while the average absolute relative errors as 14.587%, 2.112%, and 0.901%, respectively. The results demonstrate that SVM and GA-BP constitutive relationship models have better prediction accuracy than RF model in predicting the flow stress behavior of GH738 superalloy. It can provide a theoretical basis for the calculation of deformation resistance and forging tonnage under different deformation conditions, and it can also provide reliable flow stress data for numerical simulation of forging process.

>REVIEW

• Design, Properties, and Multi-field Application Progress of Porous Structures of NiTi Shape-Memory Alloy Prepared by Selective Laser Melting

  Ma Xiaolu, Wang Siyu, Shen Boran, Wu Wenzheng, Li Guiwei

  2026,55(6):1451-1464 DOI:

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  Abstract:NiTi shape-memory alloys are extensively used across various fields due to their distinctive shape-memory effect and superelasticity. Additive manufacturing technique enables the precise fabrication of high-performance complex structures of NiTi shape-memory alloys, facilitating innovative structural designs. This paper reviewed the applications of NiTi porous structures prepared by selective laser melting (SLM) in the fields of biomedical and mechanical engineering. It summarized the characteristics of various novel porous structures of SLM-NiTi across various applications, explored innovative design methodologies for these structures, and discussed their corresponding advantageous properties, which include compressive performance, superelasticity, shape-memory effect, energy absorption capability, and biocompatibility. These design methodologies and structures can provide references for the design and application of high-performance NiTi structures prepared by additive manufacturing.

>Materials Science

• Multi-scale Analysis of Residual Stress in Thermomechanical Treatment Process of 7050 Aluminum Alloy Ring

  Yang Yanhui, Liang Zhengfei, Chen Guijiang, Zhang Zhihong, Huang Guan

  2026,55(6):1465-1472 DOI: 10.12442/j.issn.1002-185X.20250042

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  Abstract:In the process of preparing and processing aluminum alloy rings, micro residual stress is generated, while macro residual stress is also generated. The release and redistribution of macro residual stress cause the deformation of the workpiece during processing and service, which will affect its dimensional accuracy. The superposition of macro residual stress and external force reduces the strength and fatigue limit of the workpiece. Under the combined action of micro-residual stress and external force, it is easy to cause stress concentration in the micro-area, so that the workpiece produces micro-cracks under far less than the yield stress, and ultimately fractures. The most important process affecting the residual stress in aluminum alloy forgings is the quenching process after solution treatment. In this paper, the macro residual stress of 7050 aluminum alloy ring during solution-cold bulging process was detected by blind hole method, and the macro finite element simulation of 7050 aluminum alloy ring during solution-cold bulging process was carried out by ABAQUS software. The macro residual stress evolution law of 7050 aluminum alloy ring during solution-cold bulging process was analyzed. It is concluded that the introduction of appropriate cold bulging process after solution quenching can greatly reduce the macro residual stress of 7050 aluminum alloy. The cross-scale analysis of residual stress is realized by the combined application of multi-scale simulation methods: Based on the crystal plastic finite element simulation method, the micro-area of interest is determined according to the macro-finite element simulation results, and the strain history of the micro-area is extracted. The strain history is applied to the micro-polycrystal model at the corresponding position by ABAQUS software to study the distribution law of micro-residual stress and its relationship with the microstructure.

• Low-Temperature Densification Mechanism and Mechanical Properties of W-Fe-C Composites

  Zhang Jian, Cheng Yu, Li Jiaqi, Wei Qinqin, Ouyang Di, Luo Guoqiang

  2026,55(6):1473-1479 DOI: 10.12442/j.issn.1002-185X.20240827

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  Abstract:The W-Fe-C composites were prepared using spark plasma sintering at various sintering temperatures, and their sintering behavior, phases, microstructure, and mechanical properties were characterized. The densification mechanism was also analyzed. The results show that as the temperature increases, the reinforcement phase in the composite transitions from Fe₆W₆C to Fe₃W₃C, and finally to Fe₂W₂C. After sintering at 1400 ℃, the sample achieves a relative density of 99.2%, with an ultimate compressive strength of 2455.15 MPa and a deformation rate of 25.42%. During the holding stage, the W-Fe-C composite exhibits a unique creep recovery stage, where the densification rate is nearly zero. When the effective stress exponent (n) is approximately 1 and 2, the estimated activation energies are 341.27 and 1005.73 kJ/mol, respectively, which are higher than those of pure tungsten. However, because the in-situ reaction promotes diffusion, the relative density of the W-Fe-C composites exceeds that of pure tungsten. This study provides a new approach for the low-temperature fabrication of tungsten-based composites.

• DOI:PreparationandLong-TermCorrosionResistanceofNovelAl2O3/BTESPT/rGOCompositeCoatings

  Shen Yonghua, Zhang Kailun, Liu Xiangyi, Yu Dazhao, Zhang Yuping

  2026,55(6):1480-1488 DOI: 10.12442/j.issn.1002-185X.20240839

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  Abstract:To improve the long-term corrosion resistance of 7075Al aluminum alloy, an alumina (Al₂O₃) coating was prepared first by cathodic liquid plasma electrolysis technology to achieve full coverage of the aluminum alloy substrate, and then a bis[3-(triethoxysilyl)propyl]tetrasulfide (BTESPT) silane coating and reduced graphene oxide (rGO) coating (BTESPT/rGO composite coating) was further prepared on the surface of the Al₂O₃ coating via dip coating and pulsed electrodeposition technology to fill the micro-cracks and micro-holes in the Al₂O₃ coating, further improving the long-term corrosion resistance of 7075Al alloy. The phase composition, surface morphology, electrochemical properties, impedance value and macroscopic surface morphology of the deposited coatings were analyzed. The results indicate that the impedance value of 7075Al coated with a single Al₂O₃ coating is still 4.6 Ω·cm² after immersion in seawater for 25 d, which is significantly higher than 3.2 Ω·cm2 of 7075Al alloy. However, several etch pits are formed on the Al₂O₃ coating because the oxygen and chloride ions in seawater enter the interior of 7075Al alloy through the micro-cracks and micro-pores in the Al₂O₃ coating. In contrast, the uniform and dense Al₂O₃/BTESPT/rGO composite coating, prepared by the pulsed electrodeposition technique at 0.8 V deposition voltage, fills the micro-cracks and micro-pores generated in the process of Al₂O₃ coating deposition. The 7075Al alloy coated with the composite coating exhibit the most positive corrosion potential and the lowest corrosion current density, indicating the lowest corrosion tendency and corrosion rate. Throughout the period of immersion in seawater for 105 d, the impedance value of 7075Al coated with Al₂O₃/BTESPT/rGO composite coating varies within the range between 5.44 Ω·cm² and 5.71 Ω·cm². Furthermore, the Al₂O₃/BTESPT/rGO composite coating exhibits only slight color change on its surface, demonstrating excellent long-term corrosion resistance in seawater.

• Preparation of Nano-tungsten Powder by Dynamic Carbothermal Reduction Method

  Zhang Bolin, Bao Kuokuo, Tang Jiayu, Ma Yunzhu

  2026,55(6):1489-1497 DOI: 10.12442/j.issn.1002-185X.20240843

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  Abstract:High-quality nano-tungsten powder is the prerequisite for the preparation of high-performance nanocrystalline tungsten alloys and cemented carbides. The tungsten powder prepared by hydrogen reduction produces WO₂(OH)₂, which leads to the growth of tungsten powder grains. The carbothermal reduction method can effectively avoid this problem. This study focused on the influence of carbothermal reduction temperature, atmosphere, time and dynamic/static process on the phase structure and particle size of the product. The results show that the purity of the product in vacuum atmosphere is higher than that in argon atmosphere. With the increase of reduction temperature, the product changes from high-valence tungsten oxide to low-valence tungsten oxide and finally to pure tungsten. When the holding time is 1 h, the average particle size of tungsten powder increases from 67 nm to 118 nm with the increase in reduction temperature from 1000 ℃ to 1100 ℃. When the reduction temperature is 1000 ℃, the average particle size of tungsten powder increases from 67 nm to 93 nm with the prolongation of holding time from 1 h to 3 h. Nano-tungsten powder with an average particle size of 67 nm can be prepared under the vacuum dynamic carbothermal reduction at 1000 ℃ for 1 h.

• Microstructure and Composition Uniformity of Triple-Melted Φ508 mm Ingot of GH4151 Superalloy

  Xu Wenliang, Zhou Haotian, Fu Baoquan, Liu Jin, Cao Guoxin, He Yongsheng, Shi Puying, Wang Kaixuan, Xie Xingfei, Lv Shaomin, Qu Jinglong

  2026,55(6):1498-1510 DOI: 10.12442/j.issn.1002-185X.20240844

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  Abstract:GH4151 is a new type of wrought superalloy used for aero-engine turbine discs. This superalloy has high-content strengthening elements, complex solidification behavior, and high cracking tendency, making it difficult to produce ingots with large size. In this study, the 2-ton GH4151 superalloy ingot with a diameter of 508 mm was prepared by the triple melting process. The solidification microstructure of the ingot was analyzed, and the composition uniformity of the ingot was evaluated. Industrial experiment show that a crack free ingot can be obtained, and the secondary dendrite arm spacings from the ingot edge to the center are 80 and 150 μm, respectively. The composition at the top and bottom of the ingot shows a good uniformity in transverse sections. The range of elements Co, Cr, W, and Mo is within 0.05wt%, and the range of the element Nb is lower than 0.07wt%. However, the variation for Al and Ti are relatively large, due to the melting loss in the axial direction. After homogenization, the segregation coefficients of the alloying elements can be controlled between 0.8 and 1.2. Superalloy bars with a diameter of 300 mm were prepared through free forging. The microstructure, properties, and flaw detection of the bars can meet the technical requirements, verifying that the prepared ingot has satisfactory metallurgical quality.

• Influence of Shot Peening on the Elemental Diffusion and Properties of Wide-Gap Brazed Joints

  Ding Kunying, Du Yimeng, Sun Yubo

  2026,55(6):1511-1517 DOI: 10.12442/j.issn.1002-185X.20240845

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  Abstract:Based on the surface shot peening treatment of Hastelloy X, this study investigated the impact of shot peening on the interfacial element diffusion and properties of wide-gap brazing joints. The microstructure and mechanical properties of wide-gap brazing joints obtained from Hastelloy X surfaces without shot peening and those treated with shot peening using ball sizes of 0.180, 0.300, and 0.500 mm were compared. SEM and EDS were used to analyze the diffusion layer structure and element distribution characteristics. The results indicate that the grain refinement effect from shot peening strengthening treatment promotes the diffusion of the melting-reducing element Si in Hastelloy X. When the shot size is 0.300 mm, the diffusion coefficient of Si in the brazing joint structure is the highest of 1.83×10^-8 mm²·s^-1; at this time, the diffusion layer is the thickest of 224.97 μm in thickness; the interface shear strength of the wide-gap brazing joint is the greatest of 543.38 MPa, which shows a 19.39% increase compared to that of the non-shot-peened sample. Additionally, theoretical calculations were conducted to determine the impact of different grain sizes under three shot peening processes on the diffusion coefficient of Si element. Theoretical calculations are combined with experimental data to elucidate the diffusion mechanism of Si in the microstructure of wide-gap brazing joints.

• 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

  2026,55(6):1518-1526 DOI: 10.12442/j.issn.1002-185X.20240846

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  Abstract:Metallographic microscope, electron backscatter diffractometer, transmission electron microscope, scanning electron microscope, X-ray diffractometer, and room-temperature tensile, tearing, and fatigue crack extension experiments were used to investigate the effect of the four final cold-rolling reductions (13%、23%、46%、68%) after intermediate annealing on the grain morphology and damage resistance of the Al-3.9Cu-0.74Li-0.68Mg alloy sheets. The results indicate that with increase in cold-rolling reduction after intermediate annealing, complete recrystallization occurs in the sheets after solid solution treatment, leading to a significant reduction in the average grain size and aspect ratio. The grains tend to become more equiaxed. The primary precipitates in the aged alloy are T₁ phase, and the size, number density, and volume fraction of T₁ phase show little variation among the four reduction levels. Quantitative calculations of the contributions of different strengthening mechanisms to the yield strength reveal that the strengthening of the alloys with the four reduction levels is mainly attributed to the precipitation strengthening of T₁ phase, contributing 335.79?366.54 MPa to the yield strength. With the increase in cold-rolling reduction, the fatigue crack growth rate of the sheets increases, resulting in deteriorated fatigue performance, while the fracture toughness shows an upward trend. Fine grains are beneficial for improving fracture toughness but detrimental to fatigue performance.

• Influence of Variable Temperature Aging on the Microstructure of Nickel-Based Superalloys

  Fu Shengyang, Cao Tieshan, Wang Wei, Chi Qingxin, Cheng Congqian, Zhao Jie

  2026,55(6):1527-1533 DOI: 10.12442/j.issn.1002-185X.20240847

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  Abstract:Nickel-based alloys undergo complex temperature variations during actual service. Thermal fluctuations may alter elemental diffusion pathways and rates, thereby affecting microstructural homogeneity. Current long-term aging studies predominantly focus on isothermal conditions, while microstructural evolution and performance degradation under non-isothermal aging remain inadequately explored. This study aims to investigate the differences in γ′ phase evolution between isothermal and non-isothermal aging in nickel-based alloys, elucidate the influence of variable temperature sequences on microstructural characteristics, and establish quantitative relationships among microstructure, aging time, and temperature, including equivalent time calculations. The results reveal that the growth kinetics of γ′ phase size in DZ411 alloy under both non-isothermal and isothermal aging follows an identical time-temperature function: the cube of phase diameter exhibits a linear dependence on aging time and temperature, with Feret ratio (FR) fluctuating within comparable ranges. Furthermore, variable temperature sequences systematically govern γ′ phase dimensions. Microstructural observations demonstrate that sequential aging from 900 ℃ to 980 ℃ produces larger γ′ phases than the reverse sequence (980 ℃-900 ℃). Quantitative analysis confirms that the average equivalent diameter (D) for the 900 ℃-980 ℃ sequence is 719 nm, which is larger than that for the 980 ℃-900 ℃ sequence (665 nm). Additionally, variable temperature sequences regulate γ′ phase morphology: rounded rectangular particles dominate in the 900 ℃-980 ℃ sequence, while near-spherical shapes prevail in the 980 ℃-900 ℃ sequence, supported by distinct FR values (1.411 vs. 1.379).

• Influence Mechanism of Gradient Microstructure on the Properties of Ti₂AlNb-Based Alloy

  Li Ping, Liu Shaofeng, Ding Ruidong, Guo Shenghua, Xue Kemin

  2026,55(6):1534-1542 DOI: 10.12442/j.issn.1002-185X.20250004

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  Abstract:Ti₂AlNb-based alloy samples with gradient microstructures were obtained by gradient extrusion at 980 °C. The gradient microstructures of Ti₂AlNb-based alloy samples were characterized by XRD, SEM and TEM, and their properties were studied by nanoindentation and nano-scratch tests. The influence of gradient microstructures on the properties of Ti₂AlNb-based alloy was investigated. The results show that the microstructure in the core of the gradient extruded Ti₂AlNb-based alloy specimen is mainly composed of the coarser B2 phase and the near-equiaxed α₂ phase distributed at the grain boundaries, and the dislocation density is low, which is mainly distributed in the B2 phase and the B2/α₂ phase boundaries. The microstructure in the edge is composed of smaller B2 phases, a large number of rod/slat-like O phases and a small number of equiaxed α₂/O (rim O) phases, and the dislocation density is high, which is mainly distributed at the interface between the slat/equiaxed O phase and the B2 phase, and in the O phase and α₂ phase. The core of the gradient extruded specimen has the lower hardness and better plasticity. The edge has higher hardness under various effects such as O-phase strengthening, fine-grained strengthening and dislocation strengthening, and the wear resistance are significantly improved. The gradient microstructure can confer the good comprehensive service performance of the Ti₂AlNb-based alloy.

• Microstructure and Properties of Low-Temperature Hot-Melted ZrTiNi Energetic Structural Materials

  Wu Zechen, Zhao Kongxun, Liu Guitao, Liu Kai, Duan Lian, Yang Hongtai, Liu Yitong, Liang Dong

  2026,55(6):1543-1549 DOI: 10.12442/j.issn.1002-185X.20250014

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  Abstract:ZrTiNi system exhibits unique low-temperature hot-melting characteristics and high chemical reactivity potential, offering promising applications in energetic warhead casings. This research presents a preliminary exploration of the low-temperature liquid phase region of ZrTiNi based on ternary phase diagram calculations. ZrTiNi alloy bulk samples with varying Zr contents (70wt%, 80wt%, and 90wt%) were prepared using a vacuum sintering process, and the microstructure, phase composition, quasi-static mechanical properties, and impact-induced reaction characteristics were studied. Results show that according to the phase diagram calculations, the ZrTiNi system has a wide liquid phase region at 900, 950, and 1000 ℃, demonstrating significant low-temperature hot-melting characteristics. Relative density and metallographic analysis results show that the Zr₇₀Ti₁₅Ni₁₅ and Zr₈₀Ti₁₀Ni₁₀ alloy samples sintered at 950 ℃ achieved near-full densification, while the Zr₉₀Ti₅Ni₅ alloy sample has a relative density of only 81.7%, with numerous pore defects remaining in the cross-section. This indicates that as the Zr content increases, the overall melting point of the alloy rises. XRD and SEM analysis results show that the ZrTiNi alloys consist mainly of Zr(Ti) solid solution as the primary phase and Ni-Zr(Ti) intermetallic compounds. Additionally, increasing Zr content promotes the formation of Zr-rich solid solution phases, which inhibits the formation of intermetallic compounds to some extent. Quasi-static compression tests reveal that both the densified Zr₇₀Ti₁₅Ni₁₅ and Zr₈₀Ti₁₀Ni₁₀ alloy samples have compressive strengths exceeding 1200 MPa, providing a solid foundation for blast loading resistance and armor-piercing penetration. In ballistic gun tests, the Zr₈₀Ti₁₀Ni₁₀ alloy projectile successfully penetrated the front steel plate at a velocity of 1029 m/s and sustained the ignition of jet fuel, demonstrating excellent impact-induced ignition properties.

• Room Temperature Mechanical Properties of Mo14Re Alloys Obtained by SPS Sintering

  Wang Ying, Lai Chen, Zheng Zhenghui, Miao Guowei, Wang Jinshu

  2026,55(6):1550-1556 DOI: 10.12442/j.issn.1002-185X.20250023

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  Abstract:Mo14Re powders were prepared by high-energy ball milling (HEBM) and spray drying-hydrogen reduction (SPHR), separately. Then, the Mo14Re alloys were obtained by spark plasma sintering (SPS). The phase structure, microstructure, element distribution, and grain size were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The deformation mechanisms of Mo14Re alloy under room temperature tension and compression were discussed. The XRD results indicate that the (101)-spacing of the Mo14Re-SPHR is smaller than that of the Mo14Re-HEBM. The EDS results show that the segregation of Re is observed at the grain boundary of the Mo14Re-HEBM, while uniform elements distribution in the Mo14Re-SPHR alloy. The room temperature compression results show that the compressive yield strength of the Mo14Re-SPHR is 679.11 MPa, higher than that of the Mo14Re-HEBM (602.71 MPa). EBSD results show that when the compression deformation is larger than 5.0%, the proportion of grains with {123}<111> as the main slip system in Mo14Re-SPHR increases, while the proportion of grains with {110}<111>and {112}<111> as the main slip systems decreases. The change trend of the three slip systems in Mo14Re-HEBM is opposite to that in Mo14Re-SPHR, resulting in a strain hardening rate of Mo14Re-HEBM higher than that of Mo14Re-SPHR. Room temperature tensile results show that Mo14Re-SPHR exhibits better plasticity and toughness.

• Temperature Dependence of Tensile Deformation Mechanism of GH4975 Superalloy for Turbine Disk

  Tai Wenbin, Zhang Rui, Wu Jingjing, Zhou Zijian, Cui Chuanyong, Zhou Yizhou, Sun Xiaofeng

  2026,55(6):1557-1566 DOI: 10.12442/j.issn.1002-185X.20250040

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  Abstract:Tensile properties, deformation mechanism, and fracture behavior of the GH4975 superalloy were investigated using optical microscope, scanning electron microscope, electron backscatter diffractometer, transmission electron microscope, and other advanced characterization techniques. The results show that the deformation mechanism of the alloy transitions from strong coupling dislocation shear at low temperatures to stacking fault and microtwin formation at intermediate temperatures. At temperatures higher than 850 °C, the dislocation bypass mechanism is activated and gradually dominates the dislocation movement with the increase in temperature. Carbide cracking dominates the failure of the alloy at low temperatures. As the temperature increases, the grain boundary strength decreases. Therefore, grain boundary cracks become the primary crack sources. At temperatures above 800 °C, the reduction in grain boundary strength and the activation of the dislocation bypass mechanism are the primary reasons for the rapid decline in alloy strength.

• Failure Behavior of Layered Aluminum Matrix Composites Fabricated by SLM-Assisted Pressure Infiltration

  Zhu Hongfei, Zhu Dezhi, Jiao Ganqing, Li Xiaoqiang, Yang Chao

  2026,55(6):1567-1572 DOI: 10.12442/j.issn.1002-185X.20250046

  Abstract(0) HTML(0) PDF(1.88 M)( 1)

  Abstract:Inspired by the nacreous structure of shells, layered HEA_P/Al-Al composites with varying framework thicknesses (0.3, 0.4, and 0.5 mm) were fabricated using selective laser melting (SLM) combined with pressure infiltration. The results indicate that the layered composites exhibit an intact internal structure, and a well-bonded interface between the reinforcement phase (HEA_P/Al) and the aluminum matrix, without the formation of interfacial reaction products. With increasing framework thickness, the flexural strength of the composites significantly improves, while the compressive strength decreases first and then increases. Additionally, the compressibility is notably enhanced. Among them, the composite with a 0.5 mm framework shows the best overall performance, with a flexural strength of 228 MPa, a compressive strength of 385 MPa, and a compressibility of 20.8%. Three-point bending tests reveal that the layered HEA_P/Al-Al composites exhibit a mixed ductile-brittle fracture mode, primarily characterized by the debonding of high-entropy alloy particles and tearing of the aluminum matrix, with the main crack propagating perpendicular to the aluminum framework. An increase in framework thickness leads to longer crack deflection paths, while mechanisms such as multi-crack propagation and microcrack diffusion effectively suppress the propagation of the main crack, thereby enhancing the overall strength and toughness of the composite. Finite element simulation results are consistent with experimental observations, confirming the inhibitory effect of the framework structure on main crack propagation. This study provides theoretical support for the structural design and mechanical performance optimization of heterogeneous composite materials.

• Effect of Hole Geometric Structure on the Oxidation Behavior of DD6 Single-Crystal Superalloy

  Hu Chunyan, Liu Xinling, Chen Xing, Liu Changkui, Tao Chunhu

  2026,55(6):1573-1582 DOI: 10.12442/j.issn.1002-185X.20250363

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  Abstract:The isothermal oxidation behavior of DD6 single-crystal superalloy with different hole geometric structure at 1050 ℃ was studied using field emission scanning electron microscope, energy dispersive spectroscope, X-ray diffractometer, and ABAQUS finite element method. The results show that at two angles of 45° and 90°, the average oxidation rate varies with the film-hole spacing, both being 0.75 mm>0.95 mm>0.55 mm>0.39 mm. The effect of film-hole spacing on the oxidation mass gain of single-crystal superalloys is more significant than that of hole angle. At the same film-hole spacing, the degree of oxidation at 45° is relatively more severe than that at 90°. Finite element analysis shows that the growth of the oxide layer on the inner wall of the hole is mainly affected by the temperature field, while the growth of the oxide layer on the surface of the hole is mainly affected by the detachment stress. As the film-hole spacing increases, the stress cancellation area gradually decreases, and the detachment stress continues to increase, reaching its peak at 0.75 mm. At this time, the oxide film detachment is most severe, and after the peak point, it shows a downward trend.

• Effect of Heat Treatment on Microstructure and Mechanical Properties of Rolled GWZ932 Alloy

  Wang Yili, Liu Jiliang, Wang Liying, Yuan Man, Wang Jianli, Yang Zhong

  2026,55(6):1583-1596 DOI: 10.12442/j.issn.1002-185X.20240836

  Abstract(1) HTML(0) PDF(4.58 M)( 1)

  Abstract:The effects of solid solution and aging treatments on the microstructural evolution and hardness of the GWZ932 alloy in the rolled state were investigated by means of optical microscope, X-ray diffractometer, Vickers hardness tester, scanning electron microscope, transmission electron microscope, and high-angle annular dark-field scanning transmission electron microscope. The results show that the alloy microstructure in the rolled state mainly consists of α-Mg, massive 18R-LPSO phase, lamellar 14H-LPSO phase, rare-earth-rich phase and Zn-Zr phase. The lamellar 14H-LPSO is almost completely dissolved into the matrix by solid solution treatment at 500 ℃ for 2 h; the elongated acicular 14H-LPSO is precipitated from the α-Mg matrix after 4 h of solid solution, and its volume fraction gradually increases with the extension of time; the volume fraction of acicular 14H-LPSO reaches 16% after 6 h of solid solution; the acicular 14H-LPSO phase dissolves and re-precipitates the lamellar 14H-LPSO (about 14.9 μm in length and 8.2 μm in width), and a small amount of undissolved acicular 14H-LPSO phase grows to form rod-like 14H-LPSO (23.4 μm in length and 1.98 μm in width). Increasing the solid solution temperature to 520 ℃, the solute atom diffusion rate is accelerated, thus the complete dissolution and re-precipitation time of lamellar 14H-LPSO is advanced to 1 and 2 h, respectively, and the size of the re-precipitated lamellar 14H-LPSO phase (12.6 μm in length, 5.1 μm in width) is smaller than that of the re-precipitated one after solid solution at 500 ℃ for 8 h. Precipitation and transformation do not occur during solid solution treatment at 520 ℃, indicating that the precipitation and dissolution of the acicular 14H-LPSO phase and its content are affected by the solid solution temperature and time. The age-hardening curves reach peak hardness under conditions of 520 ℃, 4 h+225 ℃, 64 h. On this basis, the age-hardening behaviour of the alloy after solution treatment at 520 ℃ for 4 h was investigated and the results show that the alloy reaches peak hardness after age treatment at 225 ℃ for 64 h. The room-temperature tensile strength (UTS), yield strength (YS) and elongation (EL) of the alloy under peak aging conditions are 396.3 MPa, 274 MPa, and 12.7% increase by 23.8%, 7.4%, and 69.3%, compared to those of the rolled state, respectively. The excellent strength and plasticity of the alloys arise from the precipitation of a columnar β'' phase (about 28.9 nm in length and 8.9 nm in width with an average area fraction of about 11.7%) and a basal 18R-LPSO/γ'' phase in the α-Mg matrix.

• Effect of TiC Content on Microstructure and Mechanical Properties of Mo-based Composites

  Yu Shan, Wang Yuqi, Huang Yao, Zhang Hexin, Zhao Chengzhi

  2026,55(6):1597-1604 DOI: 10.12442/j.issn.1002-185X.20240848

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  Abstract:The influence of titanium carbide (TiC) content on the microstructure and mechanical properties of molybdenum (Mo)-based composites was investigated, aiming to provide a scientific basis for the development of high-performance and heat-resistant molybdenum materials for aerospace engines. TiC/Mo composites containing 10wt%, 20wt%, and 30wt% TiC were prepared using spark plasma sintering (SPS) technique. 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 10wt% and 20wt% 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.

• Effect of Cu and Its Coated Diamond Particles on the Microstructure and Properties of Ni-based Composite Coatings

  Sun Huawei, Wu Qilong, Li Yujia, Sun Zhipeng, Liu Jianbo, Zhang Lei

  2026,55(6):1605-1611 DOI: 10.12442/j.issn.1002-185X.20250047

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  Abstract:Ni-based composite coatings with directly added Cu and Cu-coated diamond were prepared by induction heating technology. The effects of Cu addition on the microstructure, phase evolution, microhardness and wear properties of Ni-based composite coatings were investigated. The results show that the direct addition of Cu and the introduction of Cu in the form of Cu-coated diamond in the diamond-nickel-based composite coatings inhibit the generation of carbides in the nickel alloy matrix, and in the form of Cu-coated diamond, almost no carbides are observed in the nickel alloy matrix. The average microhardness of the coating with Cu-coated diamond is decreased by 76.7 HV compared to that of the direct addition of Cu; moreover, the coating shows more excellent wear resistance in the 15?45 min wear stage of the abrasive wear test.

• Morphology Regulation Path and Development Trend in Preparation Techniques of High-Purity Molybdenum Powder

  Shao Zhimeng, Jiang Honglin, Gao Bowen, Zhang Qidong, Hu Zhifang, Dou Zhihe, Yin Yanxi

  2026,55(6):1612-1624 DOI: 10.12442/j.issn.1002-185X.20250103

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  Abstract:High-purity molybdenum powder, owing to its excellent high-temperature mechanical properties, electrical and thermal conductivity, and corrosion resistance, has been widely applied in aerospace, electronic devices, nuclear energy, and powder metallurgy. This paper systematically reviewed the preparation methods of high-purity molybdenum powder, including hydrogen reduction, carbothermal reduction, spray pyrolysis, and low-temperature molten salt-assisted reduction. The effects of different preparation techniques on the purity, particle size distribution, morphological evolution, and sintering performance of molybdenum powder were analyzed. Among existing methods, hydrogen reduction is extensively applied, and research suggests that tuning reduction conditions can significantly influence impurity removal and morphological consistency. Additionally, emerging techniques, such as spray pyrolysis and low-temperature molten salt-assisted reduction, exhibit promising potential in particle size control, spheroidization, and nanostructuring, thereby enhancing powder flowability and sintering densification. Future research should further optimize precursor selection and process parameters to enhance the purity, particle size uniformity, and morphological control of molybdenum powder, meeting the growing demand for high-performance molybdenum materials in advanced manufacturing.

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• 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(65) PDF(1.64 M)(79)

  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.

• 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(56) PDF(1.04 M)(80)

  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(87) PDF(1.11 M)(52)

  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(42) PDF(1.92 M)(47)

  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(52) PDF(1.28 M)(44)

  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(54) PDF(1.42 M)(43)

  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.

• Research Status, Application and Prospect of Key Technologies in Inertial Friction Welding for Aero-engines

  WU Yanquan, ZHOU Jun

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250421

  Abstract(84) PDF(1.52 M)(27)

  Abstract:Inertial friction welding (IFW), as an advanced solid-state welding process, has been widely applied in the manufacturing of aero-engine rotor components due to its green, efficient, and superior welding quality. This paper systematically summarizes the research achievements of scholars in recent years regarding the microstructure, mechanical properties, and numerical simulation of IFW joints of aviation titanium alloys and superalloys. It also summarizes the application of large-tonnage, high-precision IFW equipment in various types of advanced aero-engine rotor components. Future research should focus on addressing key technical challenges in the engineering application of new materials and new structures. The paper also presents prospects for future development, highlighting that continuous innovation of IFW technology will provide critical technical support for achieving the high performance, lightweight design, and enhanced reliability of the new generation of aero-engines.

• Effect of different brazing temperatures on Ni-based tungsten carbide coatings prepared by vacuum brazing using flexible metal cloth as brazing filler metal

  Pu Juan, Li Xinzhu, Long fei, Shi Xiaohui, Xu Xiangping, Shiqingqing, Xu Jiuxie

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250424

  Abstract(52) PDF(1.44 M)(25)

  Abstract:A flexible Ni-based tungsten carbide metal cloth, which prepared by mixing WC powder, NiCrBSi powder and the binder, was coated on the surface of Q235 steel by vacuum brazing. It enables the repair of internal and curved surfaces of components. The effect of different brazing temperatures on the microstructure, shear strength, microhardness and wear resistance of coatings were explored. The results showed that the increasing brazing temperature did not change the microstructure composition of the coating. The interface of Ni-based tungsten carbide coating and steel substrate was mainly composed of Fe solid solution, Ni₃B, Ni₃Si compounds while the brazing seam zone was mainly composed of Ni solid solution, WC, W₂C, CrB and Cr₇C₃ compounds. With the increasing of the brazing temperature, the porosity rate and its average area of the coating gradually decreased, finally the microhardness and wear resistance of the coating enhanced. It was mainly attributed to the fact that after the flexible Ni-based tungsten carbide metal cloth melting, the NiCrBSi molten liquid improved the wetting of WC particles and filled the gap among WC particles with the increase of brazing temperature, and the coating had quite high microhardness and wear resistance. The bonding strength between Ni-based tungsten carbide coating and steel substrate increased first and then decreased with the increase of brazing temperature. When the brazing temperature was 1080 ℃, the bonding strength of the coating was the maximum of 336.5MPa. It was because the thickness of the coating/steel substrate interface compounds layer increased from 4.7 μm to 9.2 μm when the brazing temperature increased 1080℃, and the compound layer with appropriate thickness increased the bonding strength between the coating and the substrate. However, the thickness of the interface compounds layer increased to 13.9 μm when the brazing temperature increased to 1140℃, and the compounds layer with the excessive thickness led to a decrease in the bonding strength of the coating.

• Influence of Material Characteristics and Process Parameters on the Quality of 93W-4.9Ni-2.1Fe Alloy Billet Produced by Binder Jetting

  Xiao Peng, Yang Kai, Li Tengfei, Zhang Qingxia, Liu Anjin

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250425

  Abstract(33) PDF(706.02 K)(21)

  Abstract:Binder jetting is a potential low-cost method to near-net-shape fabricate large-scale complex-shaped W-Ni-Fe alloy components. Nonetheless, it faces challenges such as billets cracking during curing and debinding. Developing the manufacturing process for high-strength W-Ni-Fe alloy billets is an inevitable requirement for ensuring the large-scale application of binder jetting. In this study, a series of W-Ni-Fe alloy billets were fabricated with variables including powder particle size, binder material, binder saturation, and single-layer printing thickness. The compressive strength of the billets was tested, as well as the influence of material characteristics and process parameters on the quality of W-Ni-Fe billets was analyzed. The results indicate that the compressive strength of binder-jetted W-Ni-Fe alloy billets exhibits a negative correlation with powder particle size and single-layer printing thickness, while increasing continuously with higher binder saturation. By employing a water-based alcohol binder, the W-Ni-Fe powders with a D50 particle size of 7.62 μm, a binder saturation of 70%, and a single-layer printing thickness of 60 μm, the binder-jetted W-Ni-Fe alloy billets achieve a balance between good strength and dimensional accuracy.

• Study on the stress rupture properties of a silicon enhanced 9Cr ferritic / martensitic steel

  Yang Ning, Hu Xiaofeng, Zheng Yongfeng, Yang Zhirong, Jiang Haichang, Rong Lijian

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250429

  Abstract(25) PDF(2.44 M)(26)

  Abstract:In this work, the stress rupture properties of a silicon-enhanced 9Cr ferritic/martensitic steel (denoted as H-Si steel) at 550℃, the microstructure and hardness of the grip and gauge sections from ruptured specimens were investigated by SEM, TEM, EBSD and Vickers hardness tester. A comprehensive investigation was conducted into the microstructure evolution of H-Si steel under the coupling effect of temperature and stress and its influence on the creep behavior. The results indicate that H-Si steel exhibits good stress rupture property and the stress rupture life is 2252 h under the conditions of 550 ℃ and 167 MPa. The fracture modes under experimental stress conditions are all ductile fractures. The grip section of H-Si steel exhibits relatively stable microstructure under different stresses, with a lath width ranging from 380 to 440 nm and the hardness being approximately 230 HV. However, the microstructure of the gauge section undergoes obvious degradation due to the stress, with rapid decrease in dislocation density and significant widening lath. Correspondingly, the hardness drops obviously due to significantly decreasing dislocation strengthening and grain boundary strengthening. For instance, the hardness of the 167MPa@2252h sample decreased to 193 HV, which induces a lower high-temperature stress rupture property compared to P91 steel.

• The Effect of Precision Controlled Cooling Heat Treatment on the High-Temperature Ductility of Third-Generation Powder Metallurgy Superalloys for Turbine Disks

  Cheng Junyi, Zhao Chunling, Liu Zhaofeng, Ma Xiangdong, Xiao Lei, Guo Jianzheng, Feng Ganjiang

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250430

  Abstract(26) PDF(3.20 M)(24)

  Abstract:This study investigates the powder metallurgy superalloy FGH4113A, focusing on the design and implementation of precisely controlled cooling during the solid solution state. It examines the influence of different cooling paths on microstructural evolution and tensile properties at 800℃. The results demonstrate that the cooling path significantly affects the strength-ductility synergy. Employing a conventional continuous cooling rate of 150℃/min resulted in yield strength of 920 ± 7 MPa, an ultimate tensile strength of 1079 ± 9 MPa, and an elongation of 13 ± 3%. In contrast, a two-stage cooling process (CP2), combining an initial slow cooling (44~75℃/min) with a subsequent fast cooling (459~594℃/min), enhanced the yield and ultimate tensile strengths to 978 ± 7 MPa and 1112 ± 5 MPa, respectively, while also improving the elongation to 15 ± 1%. Further optimization of the process parameters to an initial cooling rate of 48~65℃/min followed by a second-stage rate of 275~326℃/min (CP3) achieved an elongation of 18.5 ± 1% while maintaining high strength levels (yield strength:975 ± 10 MPa, ultimate tensile strength: 1108 ± 6 MPa). Microstructural characterization reveled that the staged cooling strategy, which promotes dislocation recovery through high-temperature slow cooling and subsequently freezes the low-defect structure through medium-temperature fast cooling, effectively produces grain structures with low orientation spread and low dislocation density. Furthermore, analysis of γ" precipitation behavior indicated that the primary cooling rate governs the size of secondary γ" precipitates, while the cooling transition temperature regulates the volume fraction of tertiary γ" precipitates. The secondary cooling rate influences the size of the tertiary γ" precipitates. Through this multiscale cooperative distribution of γ" precipitates, moderately sized secondary γ" precipitates enhance strain hardening capacity by promoting the Orowan bypass mechanism, while the finely dispersed tertiary γ" precipitates compensate for the strength loss associated with coarsened secondary γ" precipitates through shearing mechanism. This work demonstrates that precisely controlled staged cooling is an effective pathway for synergistically optimizing the 800℃ strength and ductility of FGH4113A superalloy without altering its chemical composition, providing both a theoretical basis and practical guidance for the heat treatment design of this alloy.

• Crack Propagation Properties of FGH4113A Powder High-Temperature Alloy

  Zhang Gaoxiang, Long Anping, Yin Chao, Xiong Jiangying, Xiao Lei, Liu Yong

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250432

  Abstract(32) PDF(1.85 M)(23)

  Abstract:The crack propagation performance of the independently developed 3rd generation powder high-temperature alloy FGH4113A was studied, including the effects of preparation process, temperature, and frequency on crack propagation performance, and a comparison was made with similar high-temperature alloys internationally. The preparation process involved a combination of Hot Isostatic Pressing (HIP), Hot Extrusion (HEX), Isothermal Forging (ITF), and Heat Treatment (HT). Test temperatures included room temperature, 650°C, and 700°C, with test frequencies of 0.33Hz and 20Hz, analyzing the impact of frequency on the alloy"s high-temperature crack propagation performance. The comparison included similar alloy grades such as FGH95, FGH96, FGH97, FGH98, ME3, and LSHR. The results show that ppb and coarse primary γ′ phase around the grain boundary are unfavorable factors for the crack growth performance of the alloy, and increasing the grain size of the alloy is beneficial to reducing the crack growth rate. Extrusion and forging process can effectively eliminate PPB, thereby enhancing the alloy"s crack propagation resistance. The crack growth rate at room temperature is much lower than that at 650 ℃ and 750 ℃, and the crack growth rate at 0.33hz test frequency is significantly higher than that at 20Hz. Increasing the temperature and decreasing the test frequency will increase the crack growth rate of the alloy. In the stable crack propagation stage, the ITF state FGH4113A alloy exceed FGH98, LSHR and ME3 alloys, and reach the advanced level of the 3rd Powder Superalloy.

• Applications of Nanoporous Metals in Energy and Energy Storage

  Wang Ying, Zhou Zhilan, Han Gaofeng, Lang Xingyou, Jiang Qing, Han Liping, Shi Hang

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250434

  Abstract(58) PDF(2.26 M)(26)

  Abstract:Nanoporous metals, with their unique pore structure and excellent electrochemical properties, demonstrate significant application potential in the fields of energy and energy storage. Their structural characteristics confer a large specific surface area and superior conductivity, while their composition and structure are tunable. As a result, nano-porous metals play a crucial role in energy conversion applications. This paper reviews the synthesis methods and structural regulation of nanoporous metals, with a focus on their applications in electrocatalytic reactions (such as oxygen evolution reaction and hydrogen evolution reaction) and energy storage devices (such as lithium-ion batteries, potassium-ion batteries, and supercapacitors). Research indicates that nanoporous metals not only enhance catalytic efficiency but also improve battery cycle stability and energy density. However, issues such as the reproducibility of synthesis methods, long-term stability, cost, and technical challenges in practical applications require further investigation. Future research will focus on optimizing the microstructure and surface properties of nanoporous metals to achieve efficient and sustainable energy solutions.

• Effect of Trace Element Zr Addition on Microstructure and Mechanical Properties of K492M Superalloy

  xuzhiheng, yangguangyu

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250437

  Abstract(56) PDF(2.73 M)(17)

  Abstract:The influence of trace Zr element addition on the microstructure, room temperature and high-temperature mechanical properties of K492M superalloy was studied. The Zr content in the experimental alloys ranged from 60 ppm to 580 ppm. The results indicate that the addition of Zr element did not change the main phase constitution of the as-cast and heat-treated K492M alloys. The microstructure of the as-cast K492M alloy mainly consists of γ matrix phase, γ" precipitated phase, MC carbides and (γ+γ") eutectic phase. After heat treatment, the (γ+γ") eutectic phase is nearly eliminated, accompanied by the precipitation of M??C? carbides. The addition of Zr element significantly refines the grain structure of the as-cast and heat-treated K492M alloys. When the Zr content is 160 ppm, the grain structures of both the as-cast and heat-treated alloys exhibit the greatest refinement. With the increase of Zr content from 60 ppm to 580 ppm, the MC carbides in both the as-cast and heat-treated alloys tend to be refined, while Zr element addition has a minor effect on the volume fraction and size of γ" phase. The variation of Zr content has little effect on the tensile properties at room temperature and the tensile strength at high temperature (760 ℃) of the heat-treated alloys, but significantly influences the ductility at 760 ℃ and stress rupture life at 760 ℃/662 MPa. The alloy with 160 ppm Zr demonstrated the highest high-temperature elongation and the stress rupture life, which were 53.8% and 16.8% higher, respectively, compared to the alloy containing 0 ppm Zr.

• Research on the sintering and heat treatment process for fabricating strong and tough 93W-4.9Ni-2.1Fe alloy via binder jetting

  Xiao Peng, Yang Kai, Zhang Qingxia, Liu Anjin, Li Tengfei

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250438

  Abstract(42) PDF(989.50 K)(14)

  Abstract:Binder jetting is a technology that combines the advantages of both additive manufacturing and powder metallurgy, which can fabricate complex-shaped W-Ni-Fe alloy components with good mechanical properties and dimensional accuracy. Since the optimal process parameters for manufacturing strong and tough W-Ni-Fe alloy via binder jetting are still not publicly reported, this study systematically investigates the influence of the sintering temperature, sintering time, and heat treatment process on the phase composition, microstructure, and mechanical properties of 93W-4.9Ni-2.1Fe alloy produced by binder jetting. The strengthening and toughening mechanisms of different heat treatment processes (vacuum dehydrogenation and cyclic quenching) were analyzed in detail. The results indicate that the impacts of sintering temperature on the physical and mechanical properties of 93W-4.9Ni-2.1Fe alloy are much greater than sintering time, and its numerical design should exceed the powder metallurgy method by at least 20 ℃. In terms of the strengthening and toughening mechanism, vacuum dehydrogenation mainly improves toughness by toughening the Ni-Fe phase, while cyclic quenching mainly improves toughness by reducing the connectivity between W particles and then changing the fracture behavior of W phases. The synergistic use of vacuum dehydrogenation and cyclic quenching resulted in tensile strength and elongation at break of the samples reaching 938 MPa and 18.7%, respectively, which were 13.4% and 253% higher than those of the untreated samples.

• Synergistic Enhancement of Low-Dimensional Materials in Nano-Composite Electrodeposition on Magnesium Alloy Surface

  Li Zhi, Duan Huifan, Liu Chongyu, Liu Guangke, Wang Zhen

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250441

  Abstract(23) PDF(1.99 M)(8)

  Abstract:To enhance the comprehensive performance of magnesium alloy surfaces, Ni-based composite layers with zero-dimensional material ND (nano-diamond) and one-dimensional material CNTs (carbon nanotubes) added were fabricated on the surface of AZ91D magnesium alloy by nano-composite electrodeposition technology. The synergistic effect of the combination of ND and CNTs improved the microstructure of the deposited layer and enhanced its comprehensive performance. Research shows that ND, as a heterogeneous nucleation core, promotes the preferred orientation growth of Ni grains along the (111) surface, reduces the surface roughness of Ni-based deposition layers, and enhances their microstructure uniformity and density. The high specific surface area and excellent electrical conductivity of CNTs further optimize the microstructure and properties of the deposited layer. The combination of two carbon-based nanomaterials exhibits an excellent synergistic effect: the grain refinement effect of ND and the electrical conductivity enhancement effect of CNTs complement each other, significantly optimizing the deposited layer in terms of structural density, grain orientation stability, and interfacial bonding strength, further enhancing wear resistance and corrosion resistance. When the addition amounts of ND and CNTs were 12 g/L and 0.15 g/L respectively, the microstructure of the deposited layer was uniform and dense, the hardness reached 1212.7 HV, the coefficient of friction decreased to 0.34, the self-corrosion current density decreased to 1.458×10-7 A·cm-2 (three orders of magnitude lower than that of the magnesium alloy matrix), and the resistance to Pseudomonas aeruginosa was good. The antibacterial rate is as high as 90%. This study provides a theoretical basis and process reference for the synergistic reinforcement of high-performance magnesium alloy surface composite deposition layers with low-dimensional materials.

• Electrodeposition of Lattice-Structured Porous Ni-Fe Alloy

  Su Baoxue, Ruan Ying

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250445

  Abstract(49) PDF(1.40 M)(11)

  Abstract:The lattice-structured porous Ni-Fe alloys with high porosity (95-98%) were processed using electrodeposition coupled with additive manufacturing technology. Two types of lattice structural models were designed, namely tetrahedral and simple cubic. It was found that reducing the strut length or increasing the strut diameter and the inclination angle of struts relative to the horizontal direction significantly enhanced the specific surface area of the lattice structures. The influence of electrodeposition parameters on the macroscopic morphology and structural characteristics of the porous Ni-Fe alloys was analyzed. The optimal electrodeposition conditions were determined as follows: cathode current density of 2-3 A.dm_-2^{, deposition temperature of 50-60}℃, electrolyte pH of 3 and deposition time of 1 h. Under such condition, both tetrahedral and simple cubic porous Ni-Fe alloys were prepared. The uniaxial quasi-static compression tests demonstrated that the yield strength of the tetrahedral porous Ni-Fe alloy reached 45.3 MPa, which is 12.4% higher than that of the simple cubic structure. Finite element simulation results indicated that the stress under compressive loading was concentrated in the nodal regions of the alloys with these two lattice structures. The stress concentration was the main cause for the local deformation and fracture.

• Research Progress in the Design, Preparation, and Applications of Platinum-Group Metal High-Entropy Alloys

  Wang Yiqing, TANG Ke, WEN Ming, Qiubo Zhang, LIU Hongxi

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250450

  Abstract(31) PDF(1.53 M)(10)

  Abstract:High-entropy alloys (HEAs) are a class of multi-principal-element materials comprising five or more major elements in equimolar or near-equimolar ratios. These alloys exhibit distinctive properties, including high-entropy effects, severe lattice distortion, sluggish diffusion, and cocktail effects. Platinum-group metal high-entropy alloys (PGM-HEAs), renowned for their exceptional catalytic activity, corrosion resistance, and multifunctional characteristics, have demonstrated significant potential for applications in industrial and high-tech sectors such as catalysis and energy conversion. Consequently, PGM-HEAs have emerged as a pivotal subfield of HEA research. This article comprehensively reviews the design strategies, synthesis methodologies, and recent advancements in PGM-HEA applications, while also outlining future research directions and challenges.

• In-situ Laser Alloying of Fe-30Mn Biodegradable Metal and Its Biological Research

  Wang Runze, Tang Jincheng, Shan Xuepeng, Huang Zhaozhen, Li Sijing, Yan Ming

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250452

  Abstract(23) PDF(2.86 M)(8)

  Abstract:3D printing technology can fabricate complex structures to achieve personalized customization of bone implants. When in-situ alloying is employed to prepare uncommon alloys, the step of preparing pre-alloyed powder can be omitted, thereby reducing costs. In this study, block and porous Fe-30Mn alloys were prepared by PBF-LB in-situ alloying and studied the effects of different printing parameters on the performance of specimens. Insufficient laser energy input during printing leads to inhomogeneous mixing of iron and manganese, which degrades the material’s properties. Excessive energy input can cause manganese to vaporize, yielding a composition that deviates from the target. With optimized laser parameters, block specimens exhibiting a uniform Fe-Mn distribution can be obtained with an ultimate tensile strength of 644.67 MPa, an elongation of 21.61%, and a corrosion rate of 0.042 mm/year in simulated body fluid. Moreover, the resulting porous scaffold shows 49.84% porosity, a 0.2% offset yield strength of 66.11 MPa, a compressive strength at 20% strain of 170.76 MPa, and an elastic modulus of 6.41 GPa. The results of indirect toxicity tests and cell adhesion tests showed that the materials had good biocompatibility. Taken together, these results indicate that the Fe–30Mn alloy produced via PBF-LB in-situ alloying holds promise for biodegradable human bone implants.

• Overview of Graphite and Metal Brazing

  Xu Guoxuan, Chen Biwu, Hong Xianzhi, Chen Hui, Li Yuanxing

  Available online:February 13, 2026  DOI: 10.12442/j.issn.1002-185X.20250459

  Abstract(17) PDF(1.17 M)(8)

  Abstract:Graphite is widely used in aerospace, nuclear energy, and electronic heat dissipation due to its many excellent properties, and it plays an increasingly important role in modern industry. Achieving reliable connections between graphite, alloys, and metals is of great significance for achieving complementary performance of heterogeneous materials and expanding application fields. However, there are some urgent problems to be solved in the welding process between graphite and dissimilar materials, mainly including poor wetting of the brazing material, control of interface formation of brittle phases, and alleviation of interface stress. This article reviews the research progress on brazing of graphite, alloys, and metals, and elaborates on the effects of direct and indirect brazing methods on the joint performance of graphite and metals. It focuses on analyzing the solutions to the problem of poor wetting of graphite using various brazing methods, and finally provides prospects for the connection of dissimilar materials.

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