2025,Volume 54, Issue 6

>Special Issue：titanium alloy

• Inherent Strain Modeling of Residual Stress and Deformation for Laser Powder Bed Fused Artificial Knee Implants Under Different Building Schemes

  Li Chenchen, Ren Xuepeng, Pan Laitao, Shen Falei, Fang Xiaoying

  2025,54(6):1417-1425 DOI: 10.12442/j.issn.1002-185X.20240247

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  Abstract:Through a modified inherent strain model based on the minimum residual stress and deformation, three building schemes with different building postures and support structures were evaluated by finite element analysis. Results demonstrate that according to the principle of reducing the overall height of the building and reducing the support structure with a large tilt angle from the building direction, the residual stress and deformation can be effectively reduced by proper design of building posture and support before laser powder bed melting. Moreover, without the data of thermophysical property variation of Ti-6Al-4V artificial knee implants with temperature, predicting the residual stress and deformation with acceptable accuracy and reduced time cost can be achieved by the inherent strain model.

• Al and V Leaching Kinetics During Preparation of Ti6Al4V Alloy Powders by Multistage Deep Reduction Process

  Yan Jisen, Jin Fengyi, Dou Zhihe, Zhang Tingan, Xie Fang

  2025,54(6):1426-1434 DOI: 10.12442/j.issn.1002-185X.20240356

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  Abstract:The leaching process of magnesiothermic self-propagating product generated during the multistage deep reduction process was investigated. The influence of magnesiothermic self-propagating product particle size, HCl solution concentration, and leaching solution temperature on the leaching behavior of Al and V elements was investigated. Results demonstrate that the leaching rate of Al and V is increased with the rise in leaching solution temperature, the increase in HCl solution concentration, and the enlargement of magnesiothermic self-propagating product particle size. The leaching processes of Al and V are consistent with the chemical reaction control model. When the magnesiothermic self-propagation product with D₅₀ of 59.4 μm is selected as the raw material, the leaching temperature is 40 °C, and 1 mol/L HCl solution is employed, after leaching for 180 min, the leaching rates of Al and V are 24.8% and 12.6%, respectively. The acid-leached product exhibits a porous structure with a specific surface area of 3.5633 m²/g.

• Influence of Friction Condition on Cavity Filling for Large-Scale Titanium Alloy Strut Forging

  Hu Yanghu, Zhang Dawei, Tian Chong, Chai Xing, Zhao Shengdun

  2025,54(6):1462-1466 DOI: 10.12442/j.issn.1002-185X.20240277

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  Abstract:The titanium alloy strut serves as a key load-bearing component of aircraft landing gear, typically manufactured via forging. The friction condition has important influence on material flow and cavity filling during the forging process. Using the previously optimized shape and initial position of preform, the influence of the friction condition (friction factor m=0.1–0.3) on material flow and cavity filling was studied by numerical method with a shear friction model. A novel filling index was defined to reflect material flow into left and right flashes and zoom in on friction-induced results. The results indicate that the workpiece moves rigidly to the right direction, with the displacement decreasing as m increases. When m<0.18, the underfilling defect will occur in the left side of strut forging, while overflow occurs in the right forging die cavity. By combining the filling index and analyses of material flow and filling status, a reasonable friction factor interval of m=0.21–0.24 can be determined. Within this interval, the cavity filling behavior demonstrates robustness, with friction fluctuations exerting minimal influence.

• Corrosion and Copper Foil Formation Behavior of Laser Welded and Spin Formed Commercially Pure Titanium in H₂SO₄/CuSO₄ Electrolyte

  Renlina, Songyanfei, Qiliang, Yang Jian, Leixiaowei, Yangjiadian, Zhangjianxun

  2025,54(6):1467-1477 DOI: 10.12442/j.issn.1002-185X.20240793

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  Abstract:Based on the regulation of joint microstructure, electrochemical impedance spectroscopy, kinetic potential polarization and immersion corrosion were used to comparatively analyze the differences in the electrochemical corrosion morphology and post-foil formation surface morphology of laser beam weld (LBW) sample and spin formed sample, and to compare the corrosion resistance and Cu foil-forming ability of two samples in H₂SO₄/NaCl solution and CuSO₄ reducing electrolyte. Results show that in H₂SO₄ and NaCl solutions, LBW sample and spin formed sample exhibit excellent passivation ability and corrosion resistance. Both samples show uniform corrosion morphologies and similar corrosion resistance in the strong acidic solution containing Cl^-. Meanwhile, the Cu foil formation ability of the welded joint is similar to that of the spin formed sample, and both samples obtain intact Cu foils with high-quality surfaces and small differences in properties.

• Isothermal Transformation Curve and Mechanical Properties of Ti48Al2Cr2Nb Alloy Prepared by Electron Beam Melting after Heat Treatment

  liukai, lizhongwen, gaoyuxiang, yangdongye, yangqi

  2025,54(6):1521-1526 DOI: 10.12442/j.issn.1002-185X.20240070

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  Abstract:The Ti48Al2Cr2Nb(Ti4822) alloy specimens were processed by electron beam melting (EBM) technique and heat-treated. The microstructure and mechanical properties of the alloy were investigated by ultra-depth microscope, scanning electron microscope, X-ray diffractometer and microhardness tester. The kinetics of microstructure transformation was also analyzed. The EBM-formed Ti4822 alloy undergoes an α→γ transition after heating to 1360 ℃ and holding at 1220–1280 ℃. With the decrease in holding temperature, the transformation rate gradually increases, and the transformation of equiaxed γ phase increases from 20.01% to 53.32%. As the holding time increases from 5 min to 180 min, the transition rate first increases and then decreases. The kinetic relationship of the α→γ transition could be predicted using the Avrami equation: , for which k varies from –1.94×10^-3 to –21×10^-3 and n varies from 0.38 to 0.53. The microhardness of alloys held at 1280 ℃ is tested for different times, and that of alloy specimen held for 5 min reaches 506 HV_0.1.

• Topology Optimization Design and Mechanical Properties Study of Porous Titanium Alloy Based on Loading Characteristics of Human Bone

  zhangyongdi, zhaolisong, dailuyu, yangguang

  2025,54(6):1581-1587 DOI: 10.12442/j.issn.1002-185X.20240055

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  Abstract:The stress of human bone in daily activities is complex. To obtain the optimal porous titanium alloy structure suitable for bone implants, it is necessary to analyze the mechanical properties of porous structures. According to the compression, torsion, and bending loads of human bone, three kinds of porous structures (TO-C, TO-T, and TO-B) were designed and reconstructed by topology optimization method. The mechanical properties of different porous structures were studied by finite element simulation in compression, torsion and bending states. Finally, the compression test of porous specimens prepared by selective laser melting technique was carried out. The simulation results show that the compressive strength and bending strength of TO-B structure are optimal, while the torsional strength of TO-T structure is optimal. The compression test shows that the compressive strength of three structures at a porosity of 60% ranges from 188.35 MPa to 258.88 MPa and the elastic modulus ranges from 2.51 GPa to 4.16 GPa, all of which meet the requirements of human bones. By combining simulation and compression test to comprehensively analyze the mechanical properties of porous structures, it is found that TO-B structure has the best comprehensive performance and is the optimal type of porous structure for orthopedic implants.

• Hot Deformation Behavior and Constitutive Model of TA18 Titanium Alloy

  Chen Peng, Li Jinshan, Li Chongchong, Yu Yiwen, Cai Jun

  2025,54(6):1613-1619 DOI: 10.12442/j.issn.1002-185X.20240358

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  Abstract:The hot compression test of TA18 titanium alloy was carried out by Gleeble-3500 thermal simulation testing machine. The hot deformation behavior of TA18 titanium alloy was studied under the deformation temperature of 1073–1323 K and strain rate of 0.001–10 s^-1. According to the obtained true stress-true strain curve, a modified nonlinear regression constitutive model of TA18 titanium alloy was established. The results show that the flow stress of TA18 titanium alloy is sensitive to strain rate and deformation temperature. The stress-strain curves show continuous dynamic softening characteristics in the dual-phase region, and the softening mechanism is mainly dynamic recrystallization. In the single-phase region, the characteristics of steady-state flow are presented, and the softening mechanism is mainly dynamic recovery. The hot deformation activation energy of TA18 titanium alloy in dual-phase region and single-phase region is 643.2 and 148.1 kJ/mol, respectively. The correlation coefficient R and the average absolute relative error AARE of the modified nonlinear regression constitutive model are 0.986 and 7.66%, respectively, indicating that the model can accurately predict the change of flow stress of TA18 titanium alloy. Additionally, with the increase in strain rate, the dynamic recrystallization degree of TA18 titanium alloy decreases first and then increases, and the dynamic recrystallization grain size decreases gradually. With the increase in temperature, the alloy undergoes isomerism transformation, and the alloy structure changes from equiaxed structure to basketweave structure.

>Magnesium Alloy

• Effect of High-Pressure Torsion on Microstructure and Secondary Phase Distribution of Mg-3Zn-1Ca-0.5Sr Alloy

  Zhang jiazhen, Ma minglong, Zhang kui, Li yongjun, Li xinggang, Shi guoliang, Yuan jiawei, Sun zhaoqian, Shi wenpeng

  2025,54(6):1457-1461 DOI: 10.12442/j.issn.1002-185X.20240272

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  Abstract:Degradable metals, represented by magnesium and magnesium alloys, have attracted significant attention as fracture internal fixation and bone defect repairing materials due to their good biocompatibility, suitable elastic modulus and degradable properties. The Mg-3Zn-1Ca-0.5Sr (wt%) alloy is considered a competitor in the biomaterial field thanks to its unique composition of essential nutrients and excellent mechanical properties. However, the presence of coarse second-phase particles in the alloy accelerates its degradation rate and causes excessive gas formation during implantation, which restricts the alloy's potential for clinical device applications. In order to further optimize the properties of the alloy, extrusion combined with high-pressure torsion (HPT) was adopted for deformation processing. The results show that by optimizing the material processing means, the grain can be refined and broken, and the second-phase distribution can be improved, thus improving the microstructure, mechanical properties, and corrosion resistance of the alloy. After 15 cycles of HPT processing, the grains of the alloy are significantly refined to the nanometer scale, reaching approximately 98 nm. Additionally, the second-phase distribution is greatly improved, transforming the original streamlined structure into a more dispersed distribution. This change in microstructure leads to a significant strengthening effect on the alloy, with a noticeable increase in hardness from 60.3 HV in the as-extruded state to 98.5 HV.

• Effects of Extrusion Temperature on the Microstructure and Mechanical Properties of Mg-Sn Alloy

  Tong Lin, Jiang Jing, Bi Guangli, Zhao Libing, Jiang Chunhong, Chen Tijun, Li Yuandong

  2025,54(6):1507-1520 DOI: 10.12442/j.issn.1002-185X.20240069

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  Abstract:The effects of different extrusion temperatures (160, 220 and 230 ℃) on the microstructure and mechanical properties of Mg-7Sn alloy with heterogeneous grain structure were investigated using optical microscope, X-ray diffractometer, electron backscatter diffractometer, transmission electron microscope, and a universal experimental tensile machine. All three extruded alloys contain fine dynamic recrystallized grains and coarse hot-worked grains. The difference in deformability between coarse and fine grains leads to the formation of hetero-deformation induced stress (HDI). The extruded alloys form a typical basal texture, and the texture strength of the basal texture is weakened with increasing extrusion temperature, which is mainly attributed to the fact that the increase in extrusion temperature promotes the dynamic recrystallization and the activation of non-basal slip. The extruded 9E160 alloy exhibits high tensile strength at room temperature (σ_b=341.83 MPa) due to HDI strengthening, fine grain strengthening and high volume fraction of nanoscale Mg₂Sn phase precipitation strength. The increase in extrusion temperature facilitates dynamic recrystallization, resulting in grain refinement and further enhancement of the alloy's plasticity. The improved plasticity of the alloy can be attributed to both grain refinement and activation of non-basal slip systems.

• Hot Deformation Behavior and Dynamic Recrystallization Model of Mg-6Gd-3Y-1.5Zn-0.6Zr Magnesium Alloy

  Shen Jiabao, Zang Qianhao, Chen Zihan, Zhu Zhiyuan

  2025,54(6):1543-1549 DOI: 10.12442/j.issn.1002-185X.20240087

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  Abstract:To study the hot deformation behavior and related dynamic recrystallization models of Mg-6Gd-3Y-1.5Zn-0.6Zr alloy, single-pass hot compression experiments were conducted on the alloy using a Gleeble-3500 thermal simulation testing machine under deformation conditions of 350–500 °C and 0.001–1 s^-1. The dynamic recrystallization behavior was investigated by OM and TEM. Based on the true stress-strain curve, a critical strain model and a kinetics model for dynamic recrystallization were established. The results show that the dynamic recrystallization behavior of Mg-6Gd-3Y-1.5Zn-0.6Zr alloy is influenced by both deformation temperature and strain rate. With the increase in deformation temperature and the decrease in strain rate, the dynamic recrystallization of the alloy becomes more complete. After deformation, the microstructure of the alloy exhibits a typical bimodal structure. The blocky LPSO phase can promote nucleation of recrystallization through the particle stimulation nucleation (PSN) mechanism, while the lamellar LPSO phase undergoes a kink phenomenon. The analysis results of the microstructure after deformation prove that the established dynamic recrystallization model is highly consistent with the experimental results, indicating that this model can effectively predict the dynamic recrystallization behavior of the alloy.

• Microstructure and Properties of Mg-2.0Zn-0.3Mn-2.0Al-xY(0≤x≤5.0wt%) Alloys

  WANG Yu-hui, YAO Huai, ZHAO Yan-chun, XIONG Yi

  2025,54(6):1565-1573 DOI: 10.12442/j.issn.1002-185X.20240050

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  Abstract:The influence of Y content on the microstructure, mechanical properties, and corrosion resistance of as-cast Mg-2.0Zn-0.3Mn-2.0Al-xY (0≤x≤5.0wt%) alloys melted in a ZGJL0.01-40-4 medium-frequency induction furnace at 800±5 ℃ was investigated. The results indicate that the second phases in the Y-containing alloys are mainly composed of Al₂Y and (Al, Zn)₁₁Y₃ phases. With the increase in Y content, the grain size of alloy is gradually decreased, while the content and size of the second phases are gradually increased. The mechanical properties and corrosion resistance show a trend of firstly increasing and then decreasing. When the Y content is 3.0wt%, the alloy exhibits good mechanical properties and corrosion resistance due to the coupled effects of grain size and type, size, and distribution of the second phase. Its ultimate tensile strength, yield strength, and elongation are 210.47±2.26 MPa, 132.71±2.28 MPa, and (16.56±1.11)%, respectively. The average mass loss corrosion rate and hydrogen evolution corrosion rate are 4.87±0.30 and 4.69±0.31 mm/a, respectively.

• Effect of Grain Structure on Mechanical Properties and Corrosion Behavior of Deformed Mg-0.8Bi-0.35Al-0.35Ge Alloys

  Gong Shanshan, Cheng Weili, Zhang Quanfu, Song Lei, Cao Jishuan, Yu Hui

  2025,54(6):1603-1612 DOI: 10.12442/j.issn.1002-185X.20240673

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  Abstract:Mg-0.8Bi-0.35Al-0.35Ge alloys with different grain structures were prepared by rolling and extrusion processes, including homogeneous E-T2 alloy and heterogeneous R-T2 alloy. The effects of grain structure on the mechanical properties and corrosion behavior of deformed alloys were discussed. Results show that the E-T2 alloy exhibits a homogeneous equiaxed grain structure, whereas the R-T2 alloy exhibits a necklace bimodal grain structure. E-T2 alloy exhibits excellent mechanical properties with synergistic corrosion resistance, whose yield strength, ultimate tensile strength, elongation, and corrosion rate are 208.0 MPa, 274.0 MPa, 25.4%, and 0.12 mm/a, respectively. In contrast, although R-T2 alloy has higher yield strength (285.0 MPa), its corrosion resistance is inferior (0.35 mm/a). This is mainly related to the severe intergranular corrosion caused by the presence of cathode Mg₃Bi₂ phase and high-density dislocations at the grain boundary.

>Materials Science

• High-Temperature Oxidation Property and Corrosion and Wear Resistance of Laser Cladding Co-based Coatings on Pure Zr Surface

  Xia Chaoqun, Yang Bo, Liu Shuguang, Zhang Bo, Zhong Hua, Li Qiang

  2025,54(6):1397-1409 DOI: 10.12442/j.issn.1002-185X.20240270

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  Abstract:Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings, as well as the wear resistance of the coatings. Besides, the effect of changing the laser melting process on the coatings was also investigated. The oxidation mass gain at 800–1200 °C and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied. Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation. After oxidizing at 1000 °C for 1 h, the thickness of the oxide layer of the uncoated sample was 241.0 μm, whereas that of the sample with Co-based coating is only 11.8–35.5 μm. The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate, indicating that the hardness and wear resistance of the Zr substrate are greatly improved. The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt% NaCl solution.

• Deformation and Fracture Mechanism of Third-Generation Single Crystal Superalloy During In-situ Tension at Room Temperature

  Wang Rui, Li Jiarong, Yue Xiaodai, Zhao Jinqian, Yang Wanpeng

  2025,54(6):1410-1416 DOI: 10.12442/j.issn.1002-185X.20240291

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  Abstract:The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope, electron back-scattered diffractometer, and transmission electron microscope to reveal the deformation and fracture mechanism during tension. The proportion of low angle boundaries (LABs) with angles from 2.5° to 5.5° increases during tension. The change in LABs is particularly pronounced after elongation over 7%. The initiation of microcracks is caused by {111}<110> slip systems. After initiation, the crack size along the stress direction increases whereas the size extension along slip systems is suppressed. The fracture mode of the alloy is quasi-cleavage fracture and the slip lines near the fracture are implicit at room temperature.

• Numerical Simulation and Preparation of Micro-gear via Casting Forming Using Zr-based Amorphous Alloy

  lichunling, lishaobing, lixiaocheng, lichunyan, koushengzhong

  2025,54(6):1435-1444 DOI: 10.12442/j.issn.1002-185X.20240262

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  Abstract:A suction casting experiment was conducted on Zr₅₅Cu₃₀Al₁₀Ni₅ (at%) amorphous alloy. Using ProCAST software, numerical simulations were performed to analyze the filling and solidification processes. The velocity field during the filling process and the temperature field during the solidification process of the alloy melt under different process parameters were obtained. Based on the simulation results, a Zr-based amorphous alloy micro-gear was prepared via casting. The results indicate that increasing the suction casting temperature enhances the fluidity of alloy melt but induces unstable flow rate during filling, which is detrimental to complete filling. Zr-based amorphous micro-gears with a module of 0.6 mm, a tooth top diameter of 8 mm, and 10 teeth were prepared through the suction casting. X-ray diffraction and differential scanning calorimetry analyses confirm that the fabricated micro-gear exhibits characteristic amorphous structural features, demonstrating well-defined geometrical contours and satisfactory forming completeness.

• Effect of Direct Current on Wetting of Cu Substrate in Liquid Sn Solder

  Sunxuemin, Zhuweiwei, Yuweiyuan, Wubaolei

  2025,54(6):1445-1450 DOI: 10.12442/j.issn.1002-185X.20240290

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  Abstract:The wetting behavior of liquid tin (Sn) solder on copper (Cu) substrate at 250 ℃ was investigated by the wetting balance method under the action of direct current (DC). The curves of wetting balance were measured and the morphology of the intermetallic compound (IMC) precipitated at the interface were observed. Results show that DC has a significant effect on the wettability and IMC. As the current increases, the balance wetting force and the thickness of the IMC layer increase. The direction of the DC also has a certain effect on the balance wetting force and IMC layer. When the current is negative, the final balance wetting force and the thickness of the Cu₆Sn₅ layer are significantly higher than those in the positive current case, which is attributed to electromigration. The IMC precipitation at the interface provides a chemical driving force for the movement of the triple junction. The interaction of the interface atoms and the chemical reaction are enhanced by DC, thereby improving wettability. Meanwhile, the Marangoni convection caused by DC inside liquid Sn solder changes the structure of triple junction, which provides a physical driving force for the spread of the liquid Sn solder on the Cu substrate.

• Effect of Magnetron Sputtered Gas on Microstructure and Hydrogen Adsorption Performance of ZrCoRE Films

  zhou chao, Detian Li, Zhanji Ma, Gang Li, Yanchun He, Lamaocao Yang

  2025,54(6):1451-1456 DOI: 10.12442/j.issn.1002-185X.20240265

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  Abstract:ZrCoRE (RE denotes rare earth elements) non-evaporable getter films have significant applications in vacuum packaging of micro electro mechanical system devices because of their excellent gas adsorption performance, low activation temperature and environmental friendliness. The films were deposited using DC magnetron sputtering with argon and krypton gases under various deposition pressures. The effects of sputtering gas type and pressure on the morphology and hydrogen adsorption performance of ZrCoRE films were investigated. Results show that the films prepared in Ar exhibit a relatively dense structure with fewer grain boundaries. The increase in Ar pressure results in more grain boundaries and gap structures in the films. In contrast, films deposited in Kr display a higher density of grain boundaries and cluster structures, and the films have an obvious columnar crystal structure, with numerous interfaces and gaps distributed between the columnar structures, providing more paths for gas diffusion. As Kr pressure increases, the film demonstrates more pronounced continuous columnar structure growth, accompanied by deeper and wider grain boundaries. This structural configuration provides a larger specific surface area, which significantly improves the hydrogen adsorption speed and capacity. Consequently, high Ar and Kr pressures are beneficial to improve the adsorption performance.

• Effect of Mg Content on Composition of Aging Precipitates and Mechanical Properties of Al-Cu-Mn Alloy

  Zhang Han, Hao Qitang, Xue Yanqing, Yu Wentao

  2025,54(6):1489-1499 DOI: 10.12442/j.issn.1002-185X.20240065

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  Abstract:In this work, the effects of 0, 0.15%, 0.35%, 0.55% and 0.75% Mg (mass fraction) on the mechanical properties and microstructure of the Al-5Cu-0.7Mn alloy processed by foundry were investigated using microhardness test, tensile test, scanning electron microscope (SEM) and transmission electron microscope (TEM). The evolution of precipitation behavior was discussed, revealing the relationship between yield strength and aging precipitates. The results demonstrate that the aging precipitates of the Al-Cu-Mn-Mg alloys are transformed from the θ′′ phase (Al₃Cu) to the θ′ phase (Al₂Cu), with the appearance of the S phase (Al₂CuMg) and the σ phase (Al₅Cu₆Mg₂) after Mg addition. Mg-added alloys have a wider variety of phases compared to 0% Mg alloys with only the θ′′ phase, which significantly enhances the strength of the alloys. The alloy with 0.55% Mg added has excellent mechanical properties, with yield strength, tensile strength and elongation are 348 MPa, 496 MPa and 14.1%, respectively. Based on the quantitative statistics on the strengthening contribution of the precipitates, the yield strength of the 0.55% Mg alloy increases by 251.7 MPa due to aging precipitates, which is higher than that of the 0% Mg alloy (147.5 MPa). This indicates that the addition of Mg has a positive effect on the enhancement of the comprehensive mechanical properties of Al-Cu-Mn alloy.

• Microstructure Evolution and Element Segregation of Semi-Solid Copper Alloy Slurry Prepared by Severe Plastic Deformation and Isothermal Treatment

  Zhang Qing Biao, Chen Lei, Sun Zhen, Tao Yang, Chen Hao, Xiao Han

  2025,54(6):1500-1506 DOI: 10.12442/j.issn.1002-185X.20240068

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  Abstract:The microstructure evolution and element segregation of semi-solid ZCuSn10P1 copper alloy slurry prepared by large plastic deformation strain-induced melting activation method were studied, and the influence of isothermal treatment time on slurry characteristics was analyzed. The results show that the average grain size increases from 21.1 μm at 1 min to 68.8 μm at 10 min with the increase in isothermal treatment time at 900 ℃. The shape factor firstly increases and then decreases, from 0.31 at 1 min to 0.76 at 5 min, and then decreases to 0.56 at 10 min. The liquid phase ratio increases from 3.1% at 1 min to 9.3% at 5 min and remains stable. The diffusion layer thickness of Tin increases from 0.422 μm at 1 min to 1.704 μm at 10 min, and the content of Tin in liquid film and grain core is exponentially related to the isothermal time. The optimum isothermal treatment condition is 900 ℃ for 5 min. At this time, the average grain size, shape factor and liquid island size of the semi-solid copper alloy are 29.6 μm, 0.76 and 3.1 μm respectively. The average grain size and shape factor of the semi-solid copper alloy prepared by conventional strain-induced melting activation method are reduced by 58.9% and increased by 28.8%, respectively. The liquid island size is reduced by 31.1%, and the segregation of tin element is weakened.

• Effect of Pre-Strain Treatment on High Temperature Tensile Properties of A Novel Ni-Based Superalloy

  ShanXuanming, Gao Yubi, Wang Xingmao, Ding Yutian

  2025,54(6):1527-1534 DOI: 10.12442/j.issn.1002-185X.20240076

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  Abstract:The effects of pre-strain treatment (10%–50%) on microstructure and tensile properties of a novel Ni-based superalloy at high temperature (600 ℃) were studied by EBSD, SEM and TEM. The results show that a large number of dislocation and stratification substructures are prefabricated in the alloy, and the strength of the alloy at 600 ℃ increases monotonically with the increase in the pre-deformation amount, while the elongation of the alloy decreases first and then increases. At the same time, when the pre-deformation amount is 50%, the yield strength of the alloy sample increases to 1516 MPa, the ultimate tensile strength is 1677 MPa, and the elongation after fracture is 2.47%. In addition, the strength improvement is mainly attributed to the L-C lock interaction formed by the intersection of the dislocation with the γ′ phase, the stacking fault, and the lamination fault on different (111) planes, which provides a new strengthening method for the regulation of high performance Ni-based superalloys.

• Laser Additive Manufacturing and Arc Ablation Behavior of Nb/Cu Functionally Gradient Cathodes

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

  2025,54(6):1535-1542 DOI: 10.12442/j.issn.1002-185X.20240081

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  Abstract:Functionally gradient cathodes (FGC) realize the combination of ablation-resistant surface and conductive matrix, which can effectively extend the cathodic service life. Nb/Cu FGC, with Nb layer and Cu as surface and matrix, respectively, was prepared by laser cladding. The microstructure, composition, and the phase information were characterized. The microhardness and thermal conductivity of the FGC were tested. Furthermore, the cathodic discharge and ablation behavior in Ar atmosphere were investigated. Results show that several scattered cathode spots appear and densely distributed ablation craters are observed. The Nb/Cu FGC displays relatively moderate ablation behaviors. The average ablation rate of Nb/Cu FGC (1.61 μg/C) is 26.1% lower than that of Cu cathodes (2.18 μg/C), as ascribed to the synergy of ablation resistant Nb surface and the highly-conductive Cu matrix. Nb/Cu FGC exhibits the potential in arc plasma applications.

• Preparation of Y₂O₃ Particle Reinforced Ni-based Alloy by Spark Plasma Sintering

  Zhencen Zhu, Xiaoqiang Li, Cunliang Pan, Shengguan Qu

  2025,54(6):1550-1557 DOI: 10.12442/j.issn.1002-185X.20240089

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  Abstract:Referring to the composition of MA754 alloy, Ni-based alloy powders with high melting point containing Ti and Nb as framework, as well as low melting point Ni-based alloy powders with B and Zr as wetting agents, were prepared by high-energy ball milling. A Ni-based ODS alloy with excellent performance was prepared by spark plasma sintering after mixing two kinds of powder in the optimal ratio. The influence of sintering temperature and the content of low melting point powder in composite powder on the microstructure and mechanical properties of the alloy was studied. The results show that dispersed oxides can be observed in the alloy structure prepared by this method, and the room-temperature strength is improved compared to MA754 alloy, but the plasticity decreases. As the content of low melting point alloy in the composite powder increases, the alloy structure firstly becomes small and uniform, and then acicular aggregate phases and coarse block phases appear. The tensile strength of the alloy shows a trend of firstly increasing and then decreasing. When the sintering temperature is 1025 ℃ and the content of low melting point alloy powder in the composite powder is 3wt%, the alloy has the highest tensile strength of 951.87 MPa, which is significantly improved compared with commercial MA754 alloy. Additionally, the maximum elongation is 11.18%.

• Hydrothermal Synthesis of YSZ Powder and Preparation of Its SPS Bulk Materials

  Xie Jing, Xie Wangnan, Sun guodong, Li Hui, Jia Yan, Zhao Peng

  2025,54(6):1558-1564 DOI: 10.12442/j.issn.1002-185X.20230794

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  Abstract:Yttria-stabilized zirconia (YSZ) powder was synthesized by hydrothermal method using yttrium nitrate hexahydrate and zirconium oxychloride as yttrium and zirconium sources, respectively. Then, YSZ bulk material was prepared by spark plasma sintering (SPS) method using the obtained YSZ powder as raw material. The effects of sintering temperature and sintering pressure on the microstructure, Vickers hardness, fracture toughness and other mechanical properties of the bulk materials were studied. The results show that pure YSZ powder can be obtained by hydrothermal method when the content of yttrium is 10%. With the increase in SPS temperature and pressure, the density of YSZ bulk material is gradually increased, and YSZ bulk with a porosity of only 2.6% is prepared at 1400 ℃/50 MPa. With the increase in sintering temperature, the Vickers hardness, nano-hardness and elastic modulus of the bulk material are first increased and then decreased. The increased sintering pressure is conducive to the improvement of the mechanical properties of the bulk material, and the maximum values will be reached at 1400 ℃/50 MPa, when the Vickers hardness, nano-hardness and elastic modulus are 13.11±0.2 GPa, 15.67±0.21 GPa and 350.43±6.19 GPa, respectively. The fracture toughness is decreased first and then increased with the increase in sintering temperature, while decreased with the increase in sintering pressure, which reaches the maximum of 5.4±0.27 MPa·m^1/2 at 1400 ℃/20 MPa.

• Effects of W Content on Microstructure and Mechanical Properties of Ti-W Composites

  Zhu Ke, Huang Jin, Xiao Yong, Zhang Jian, Luo Guoqiang, Shen Qiang

  2025,54(6):1574-1580 DOI: 10.12442/j.issn.1002-185X.20240051

  Abstract(0) HTML(1) PDF(4.30 M)( 6)

  Abstract:Ti-W composites with different W additions were prepared by spark plasma sintering technique and their phase composition, microscopic morphology, mechanical property, and fracture morphology were investigated. The results show that W element can refine the particle size of composite powder and promote the interfacial bonding. The relative density of Ti-W composite with 5at% W addition content increases from 92.33% (pure Ti) to 98.49%, the microhardness increases from HV_0.5 315 to HV_0.5 740. The compressive strength of Ti-W composites is also significantly improved, and the compressive yield strength of Ti-W composite with 25at% W addition content (Ti-25W) is as high as 2267 MPa. When the W content is lower than 20at%, the lamellar α/β-Ti phase and precipitated nano-martensite play a major role in strengthening; when the W content is 25at%, the unsolidified W particles and W-rich solid solution play a role in particle strengthening and solid solution strengthening.

• Corrosion Resistance of 5vol%TiBw/TA15 Composite with Mesh Structure

  Feng Yangju, Wang Wei, Lu Yunbing, Lei Yucheng

  2025,54(6):1588-1595 DOI: 10.12442/j.issn.1002-185X.20240056

  Abstract(0) HTML(1) PDF(3.08 M)( 6)

  Abstract:The 5vol%TiBw/TA15 composite with mesh structure was prepared by low-energy ball milling in conjunction with vacuum hot pressing sintering technique, and its corrosion resistance was investigated. Pure TA15 and 5vol%TiBw/TA15 composite were subjected to electrochemical corrosion tests. The open circuit potential, polarization curves, and electrochemical impedance spectra of the two materials were measured and compared in 3.5wt% NaCl corrosion solution. The results show that compared with pure TA15, the composite reinforced by 5vol% TiBw with mesh structure has a lower self-corrosion current density (0.033 μA·cm^-2), higher polarization resistance value (42 993 kΩ·cm²), and fewer corrosion pits, demonstrating superior corrosion resistance. This phenomenon is attributed to the presence of TiBw reinforcement, which accelerates the formation of a stable TiO₂ passivation film on the surface of the 5vol%TiBw/TA15 composite compared to pure TA15 during the electrochemical corrosion process.

• Effect of Be on Transformation of Fe-containing Phase of Al-Si-Mg Alloy During Heat Treatment

  Sun Yetao, Feng Jietao, Yin Jiaxin, Wang Rong, Wang Deqing, Li Chengjun, Wang Yingmin, Fang Canfeng

  2025,54(6):1596-1602 DOI: 10.12442/j.issn.1002-185X.20240098

  Abstract(0) HTML(0) PDF(7.17 M)( 7)

  Abstract:To investigate the effect of Be on the transformation of Fe-containing phases during solution treatment, a series of experiments combining Be with different solution treatment processes were designed, and the intrinsic relationship between its effect on the morphology of eutectic silicon and Fe-containing phases and the mechanical properties was studied, aiming to improve the overall performance of the hypoeutectic Al-Si-Mg alloy. The results show that Be delays the decomposition of Mg₂Si phase and promotes the transformation of π-AlSiMgFe phase to β-AlFeSi phase. The accelerated transformation of the structure and morphology of π-AlSiMgFe phase not only enhances the strengthening effect, but also weakens the cleavage effect of π-AlSiMgFe phase on the matrix, thus synchronously improving the strength and plasticity of the alloy.

• Milling Behavior and Failure Mechanism of PVD-TiN/AlTiN Nano Composite Coated Plate-Grained Cemented Carbide Tools

  Zhong Zhiqiang, Chen Yi, Xue Yan, li shengyan, yinlei, su guojiang

  2025,54(6):1620-1629 DOI: 10.12442/j.issn.1002-185X.20240044

  Abstract(0) HTML(1) PDF(9.79 M)( 6)

  Abstract:Taking the traditional cemented carbide WC-10Co-0.6Cr₃C₂ (wt%) substrate as the reference object, WC-10Co-0.4TiC-0.6Cr₃C₂ (wt%) plate-grained cemented carbide tools were prepared by Ti induction method, and PVD-TiN/AlTiN nano multilayer composite coatings were deposited on the surfaces of the two groups of tools. The milling behavior of two coated tools in the machining process of 316L stainless steel was studied. The results show that under dry milling, the main failure mode of tools are wear and edge collapse, and the milling life of PT tool (based on the plate-grained cemented carbide) is 48% longer than that of CT tool (based on the traditional cemented carbide). Under wet milling, the main failure modes of tools are coating peeling and edge collapse, and the milling life of PT tools is 41% higher than that of CT tools. Under both dry and wet milling conditions, the first macro thermal crack time on the surface of PT tool is later than that of CT tool. PT tool has a longer wear stability period in the milling process. Its excellent ability to resist crack initiation and propagation is an important reason for the improvement in the milling life of coated tool (PT) based on plate-grained cemented carbide.

>Reviews

• Review on Characteristic and Mechanical Behaviour of FGMs Prepared by Additive Manufacturing

  Sainath Krishna

  2025,54(6):1478-1488 DOI: 10.12442/j.issn.1002-185X.20250002

  Abstract(1) HTML(3) PDF(1.05 M)( 6)

  Abstract:The functionally graded materials (FGMs) are obtained by various processes. While a few FGMs are obtained naturally, such as oyster, pearl, bamboo, etc, additive manufacturing (AM), known as 3D printing, is a net-shaped manufacturing process employed to manufacture complex 3D objects without tools, molds, assembly, and joining. Currently, commercial AM techniques mostly use homogeneous composition with simplified geometric descriptions, employing a single material across the entire component to achieve functional graded additive manufacturing (FGAM), in contrast to multi-material FGAM with heterogeneous structures. FGMs are widely used in various fields due to their mechanical property advantages. Because FGM plays a significant role in the industrial production, the characteristics and mechanical behaviour of FGMs prepared by AM were reviewed. In this review, the research on FGMs and AM over the past 30 years were reviewed, suggesting that future researchers should focus on the application of artificial intelligence and machine learning technologies in industry to optimize the process parameters of different gradient systems.

• Advance in Formation Mechanisms of Porosity Defects and Regulatory Measures in Laser Beam Welding of Magnesium Alloys

  wang shuai, Liu Zeyu, Ye Jianlin, Wang Ge, Guo Yangyang, Pu Xuanyu, Zeng Rongchang, Ren Lingbao, Shan Zhiwei

  2025,54(6):1630-1640 DOI: 10.12442/j.issn.1002-185X.20250028

  Abstract(2) HTML(3) PDF(1.85 M)( 9)

  Abstract:Laser beam welding (LBW) has emerged as one of the most promising connection techniques for lightweight equipment fabricated by magnesium alloys due to the less deformation, narrow heat-affected zone, and excellent welding efficiency. However, a variety of porosity defects are commonly found in the laser welded joints. The causes of laser-welded pores are complicated. The number, size and distribution characteristics of porosity affect the mechanical properties of magnesium alloy joints, and thus seriously affecting the reliable applications of magnesium alloy lightweight equipment. This study reviewed the mechanism of pores formation in the microstructure of laser welding joints of magnesium alloys, and discussed the influence of porosity on mechanical properties. The pore manipulation was proposed. The key basic research and applications of LBW of magnesium alloys were pointed out. This review may provide valuable insights for the development of joining and manufacturing technology of magnesium alloy lightweight parts in automotive and aerospace fields.

• Research Progress in Shape Memory Alloys and Their Applications in Aviation Field

  Guan Weimian, Wang Xing, Zhao Jianguo, Li Shijian, Liu Yanmei, Liu Biao, Bai Jing, Guan Ziqi

  2025,54(6):1641-1652 DOI: 10.12442/j.issn.1002-185X.20240046

  Abstract(3) HTML(0) PDF(4.85 M)( 9)

  Abstract:Shape memory alloys (SMA) possess both the shape memory effect and superelasticity. This material plays a significant role in the aviation field, and it is crucial to understand its types, mechanisms, preparation, and processing techniques. This review focused on the research progress of SMA in aviation applications. Considering the material characteristics of SMA, its application research in aviation fields was analyzed, such as pipe joints, deformable wings, air intake fairings, and intelligent noise reduction nozzles. The research findings indicate that as aviation manufacturing technology advances, the application of SMA is expected to evolve towards high temperature resistance, lightweightness, and intelligence.

Online First

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

  lujianqiang, wanglinlin, oumeiqiong, houkunlei, wangmin, wangping, mayingche

  Available online:June 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240125

  Abstract(92) PDF(0.00 Byte)(227)

  Abstract:As the thrust-to-weight ratio of the aero-engine increases, the turbine inlet temperature increases significantly, leading to a significant increase in the service temperature of other key hot-end components. In the process of service, nickel-based superalloys need to withstand the combined effect of high temperature, stress and environment, and the alloy surface will inevitably occur high temperature oxidation. High temperature oxidation often preferentially penetrates along grain boundaries, resulting in micro-voids and micro-cracks at grain boundaries, which seriously affects the properties of the alloy. Therefore, it is necessary to explore ways to improve the oxidation resistance of alloys at high temperatures. In this work, the effect of Hf on oxidation behavior of K4800 nickel-based superalloy was studied. The results show that the oxidation weight gain of K4800 and K4800+0.25Hf alloys increases with the extension of exposure time during static oxidation at 800℃ and 850℃, and the oxidation kinetics curves follow the parabola rule. However, the initial static oxidation rate of K4800+0.25Hf alloy (0.0265 g/m2·h at 800°C for 20 h and 0.0617 g/m2·h at 850°C for 20h) is lower than that of K4800 alloy (0.041 g/m2·h at 800°C and 0.0669 g/m2·h at 850°C). The oxide layer of the two experimental alloys comprises an outer oxide layer and an inner oxide layer.The outer oxide layer primarily consists of dense Cr2O3, while the inner oxide layer mainly contains dendritic Al2O3. However, with the Hf content increasing from 0 wt.% to 0.25 wt.%, the thickness of the Cr2O3 outer oxide layer decreases from 2.71 μm to 2.17 μm after oxidation at 800°C for 1000 h and from 5.83 μm to 4.09 μm after oxidation at 850°C for 1000 h.The results of EPMA analysis indicate the formation of HfO2 at the grain boundary of the oxide layer in the K4800+0.25Hf alloy, promoting the formation of Al2O3 around HfO2 and accelerating the growth of Al2O3. The presence of Al2O3 and HfO2 at the grain boundary contributes to reducing the outward diffusion rate of Cr3+ and delaying the thickening of the Cr2O3 oxide layer. Consequently, the addition of Hf enhances the oxidation resistance of the K4800 alloy.

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

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

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

  Abstract(75) PDF(1.46 M)(126)

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

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

  Yu Shan, WangYuqi, HuangYao, ZhangHexin, ZhaoChengzhi

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

  Abstract(36) PDF(1.70 M)(114)

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

• Investigation on the heterogeneous deformation behavior and strain rate sensitivity of the metastable β-Ti-1023 alloy

  wangxueli, lifuguo, jiapenglai, zhangzhimin, wangqiang

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240576

  Abstract(71) PDF(13.09 M)(119)

  Abstract:The digital image correlation (DIC) technology has been used to track promptly the strain distribution and local strain evolution under different strain rates in this paper, and the propagation behavior of strain distribution and its strain rate sensitivity have been investigated. And the electron backscatter diffraction (EBSD) has been selected to analyze the microstructure evolution, the distribution of stress induced α" martensite transformation (SIMT) and martensite twinning after deformation. Besides, the scanning electron microscope (SEM) has been adopted to observe the fracture morphology of the material. The following conclusions can be drawn: (1) The strain distribution evolved from an approximate uniform distribution to a non-uniform distribution, then showing a phenomenon of strain concentration, and ultimately occurring fracture in the strain concentration area, and the significanted necking phenomenon has been displayed at the low strain rates. (2) A clear double yield phenomenon has been exhibited in the stress-strain curves with producing higher strain hardening rates at the low strain rates, it means that the materials show a negative strain rate sensitivity effect. (3) The content of α" martensite increased significantly, the grain size refined obviously, and the average values of KAM (Kernel average misorientation) and GNDs (Geometrically necessary dislocations) increased dramatically with the strain rate decreasing, it indicates that the SIMT increase can contribute to the accumulation of dislocation density in the deformed sample and be more conducive to the coupling effect of multiple plastic deformation mechanisms. (4) The fracture morphology mainly occur tensile fracture by the aggregation of ductile dimples and voids. The stress on the dimples rapidly develops from unidirectional tension to triaxial tension resulting in sufficient growth of the dimples during the deformation process. Therefore, the ductile fracture characteristics dominated in the low strain rates deformation with promoting the occurrence of this phenomenon.

• Application Research of Nanofibrous LSCF@GDC Composite Cathode in Reversible Solid Oxide Fuel Cells

  Sun Xu, Zhang Bingqi, Zhao Jingqi, Sun Yue, Liu Xin, Zhou Hongyang

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240581

  Abstract(130) PDF(1.74 M)(210)

  Abstract:Reversible solid oxide cells (RSOCs) can theoretically achieve a relatively high energy conversion efficiency. The key to its widespread application is to further enhance the current density so as to increase hydrogen production and output current. However, insufficient catalytic activity of the oxygen electrodes has become an obstacle to the application of reversible solid oxide cells. The paper successfully fabricates composite LSCF@GDC nanofibers with reversible oxygen evolution and reduction electrocatalytic activity by employing electrospinning technology. Compared with the oxygen electrodes materials synthesized by the traditional sol-gel method, the three-dimensional nanofiber structure oxygen electrodes described greatly reduces the battery polarization impedance, increases the discharge power density and electrolytic current density, and shows better reversibility and stability in long-term tests. The research confirms the advantage of electrode morphology engineering control in expanding the catalytic interface and reaction sites.

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

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

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

  Abstract(49) PDF(9.52 M)(198)

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

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

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

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

  Abstract(81) PDF(1.91 M)(215)

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

• Study on hot cracking sensitivity of Wrought superalloy GH4975 with high alloying

  ZHU Xing, JIANG He, DONG Jianxin, WAN Zhipeng

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240603

  Abstract(51) PDF(7.66 M)(199)

  Abstract:In order to study the hot cracking sensitivity of high alloying refractory superalloy GH4975, the crack morphology and microstructure characteristics of the ingot of GH4975 were observed, and the causes of hot cracking were analyzed by means of solidification behavior and thermodynamic calculation. The results show that the crack spreads along grain boundaries and dendrites, and the equiaxed crystal region has a greater tendency to crack than the columnar crystal region. Shrinkage holes are easy to appear in the center of the ingot. The formation of continuous shrinkage holes leads to insufficient overlap between dendrites, which is easy to be pulled apart under the action of stress to form a crack source. At the same time, the segregation of Al, Ti and Nb elements between dendrites is serious, and complex precipitates, especially a large number of (γ+γ ") eutectic phases, promote the nucleation and propagation of cracks. JMatPro"s calculation shows that GH4975 alloy has a large shrinkage rate in the solid-liquid two-phase zone and a wide range of non-complementary temperature, which is easy to form a shrinkage hole and become a crack source. Meanwhile, the linear expansion coefficient of the alloy changes greatly in the non-complementary temperature range, and the crack is easy to expand.

• Study of Electric Parameters to regulate Corrosion Resistance of MAO Coating on TC4

  Wang Sheng, Zhang Yali, Liu Haoming, Liu Yuchang, Wang Haoxu, Ma Ying, Li Yuandong

  Available online:April 10, 2025  DOI: 10.12442/j.issn.1002-185X.20240609

  Abstract(59) PDF(1.33 M)(144)

  Abstract:This paper investigates the effects of voltage, pulse frequency, duty cycle and processing time on the corrosion resistance of micro-arc oxidised TC4 titanium alloy coatings using polar analysis of variance (ANOVA), with a subsequent objective of exploring the significance relationship and the optimum combination of the factor levels of the electrical parameters. Concurrently, an investigation was conducted into the mechanisms through which electrical parameters influence the corrosion resistance of the film layer, with a particular focus on its morphology and physical composition. A regression equation is established to facilitate regulation of the corrosion resistance properties of micro-arc oxidized films through manipulation of electrical parameters. The findings indicate that the duty cycle exerts the most significant influence on the electrochemical corrosion resistance of the membrane layer, the next most influential factors are pulse frequency and voltage, processing time was observed to have a comparatively lesser effect. The duty cycle and pulse frequency influence both structure and performance characteristics of the film layer by altering arc ignition discharge duration as well as arc quenching cooling times. An increase in voltage, duty cycle, processing time, or a decrease in pulse frequency can result in an enhanced power output from the power supply, this leads to an increase in film thickness along with larger pore sizes within microporous structures while reducing densification. Additionally, it promotes more efficient generation of Al2TiO5 within the film layer, however, this ultimately results in diminished electrochemical corrosion resistance. The results of the correlation coefficient testing demonstrate a strong relationship between the dependent and independent variables within the established regression equation. This finding provides theoretical support for predicting methods aimed at regulating performance characteristics in titanium alloy micro-arc oxidation films.

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

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

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

  Abstract(119) PDF(1.31 M)(205)

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

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

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

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

  Abstract(101) PDF(2.96 M)(230)

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

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

  Zhu Dezhi, Chen Haipeng, Cai Liangfu

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

  Abstract(95) PDF(2.11 M)(187)

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

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

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

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

  Abstract(92) PDF(2.83 M)(203)

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

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

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

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

  Abstract(283) PDF(2.66 M)(190)

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

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

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

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

  Abstract(86) PDF(3.72 M)(146)

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

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

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

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

  Abstract(92) PDF(3.00 M)(105)

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

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

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

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

  Abstract(77) PDF(2.06 M)(192)

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

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

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

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

  Abstract(39) PDF(4.76 M)(245)

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

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

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

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

  Abstract(118) PDF(3.89 M)(49)

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

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

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

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

  Abstract(87) PDF(4.07 M)(249)

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

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