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    2024,Volume 53, Issue 2

      >Special Issue:titanium alloy
    • Han Lihong, Yang Shangyu, Wang Jianjun, Luo Sheji, Li Dan, Liu Ming

      2024,53(2):350-356 DOI: 10.12442/j.issn.1002-185X.20230291

      Abstract:The oxidation behavior, oxidation morphology, and oxidation products of pure Ti joint welded by tungsten inert gas welding technique at 550 °C for different durations (2, 4, 6, and 8 h) and those at different temperatures (650, 750, 850, and 950 °C) for 4 h were investigated. Results show that at 550 °C, the oxidation time has a slight influence on the oxidation behavior of welded joint. The oxidation temperature has a significant impact on the oxidation behavior, and the higher the temperature, the more severe the oxidation of welded joints. The oxidation kinetics is very close to the quasi-linear law at low temperatures. With increasing the temperature, the oxidation rate is increased exponentially. Additionally, the oxidation products generated on the surface of welded joint are TiO2 with anatase and rutile structures, and the temperature barely has effect on the TiO2 type. The oxidation process of pure Ti welded joint can be described as follows: oxygen atoms are absorbed on the surface; oxides preferentially nucleate in the defective zone; oxides grow laterally and the oxidation film becomes thicker. At relatively higher temperatures, the cracks or voids appear in the oxidation film, which become the transmission channels of O atoms, leading to the high diffusion rate of O and Ti atoms and high oxidation rate.

    • Huang Junyuan, Zhang Wei

      2024,53(2):357-364 DOI: 10.12442/j.issn.1002-185X.20230534

      Abstract:Ti6Al4V specimens prepared by electron beam selective melting were heat-treated for 1, 3, 5, 7, and 9 h, and the Tafel and electrochemical impedance spectroscopy experiments were conducted to discuss the behavior and mechanism of electrochemical corrosion. Through the modification mechanism analysis of corrosion performance, it is found that the more the <111> crystal orientations, the greater the proportion of small-angle grain boundaries, the larger the grain diameter, and the better the corrosion resistance. The specimen after heat treatment for 5 h has the most uniform <111> crystal orientations. The proportion of small-angle grain boundaries is the highest of 56.2%, the grain intercept is 5.252 μm, and the corrosion resistance is optimal with corrosion current of 0.037 μA/cm2.

    • Gao Yushe, Xue Xiangyi, Liu Xianghong, Gao Huixian, Wang Jianguo, Du Yuxuan

      2024,53(2):371-376 DOI: 10.12442/j.issn.1002-185X.20230450

      Abstract:A new type of near-β titanium alloy (Ti555211) was investigated. This alloy has excellent plasticity, high specific strength, and excellent comprehensive properties, which is widely used in the aerospace and chemistry industries. Through the 3×3 orthogonal experiments, the influences of different stages of two-step annealing treatment (solution temperature, aging temperature, aging time) on the mechanical properties and microstructures of Ti555211 titanium alloy were investigated. Results show that with increasing the solution temperature and decreasing the aging temperature, the alloy strength is increased. The elongation is increased with decreasing the solution temperature and increasing the aging temperature. After treatment of 820 °C/2 h/air cooling and 580 °C/12 h/air cooling, the alloy has better plasticity, and its tensile strength reaches 1333 MPa, which is higher than the strength index (1080 MPa) of similar alloys by 20%. The elongation of the Ti555211 titanium alloy is 12%, which is higher than the plasticity index (5%) of similar alloys by 140%.

    • Cao Hui, Wang Jingqi, Zhou Baocheng, Yu Zhaoliang, Yang Wenle, Li Haiyan, Liu Jianhui, Feng Ruicheng

      2024,53(2):396-408 DOI: 10.12442/j.issn.1002-185X.20230292

      Abstract:In order to investigate the effect of γ/α2 phase interface on the deformation mechanism and mechanical properties of TiAl alloy during bombardment process, the supersonic fine particle bombardment of dual-phase TiAl alloy was simulated by molecular dynamics. Results show that the impact deformation mechanisms of γ/α2 models with different thickness ratios are different, and the deformation is mainly concentrated at the γ phase and interface. With decreasing the γ phase thickness, the dislocations in contact with the phase interface are firstly absorbed by the mismatched dislocation network, then they are nucleated at the phase interface, and eventually the dislocations pass through the phase interface, entering the α2 phase. Shockley dislocation is the main dislocation type in the impact process, and incomplete stacking fault tetrahedron forms in the specimen. After impact, uniaxial tensile simulation and nano-indentation simulation were conducted to measure the strength and surface hardness of the specimens. The main deformation mechanisms of specimens with different thickness ratios are the phase transformation, twins, and stacking faults during tensile process. Compared with other specimens, TiAl alloy with thickness ratio of 1:3 has the highest yield strength, the highest hardness, and the highest elastic modulus after impact.

    • Liu Xiaoyan, Li Shuaikang, Yang Xirong

      2024,53(2):409-416 DOI: 10.12442/j.issn.1002-185X.20230015

      Abstract:To study the intricate mechanical behavior of ultrafine-grained(UFG) pure titanium under high temperature and high strain rate loading, a model that can accurately describe its dynamic mechanical behavior was established. The dynamic impact test of UFG pure titanium was carried out at loading temperatures of 300~450℃ and strain rates of 2000~3000 s-1, the true stress-strain curves were also obtained. The results show that under the studied conditions, the true stress-strain curves show obvious double stress peaks, the annihilation and rearrangement of dislocations at grain boundaries and the subsequent formation of adiabatic shear bands(ASB) are the main factors for the two stress reduction. UFG pure titanium shows positive strain rate sensitivity and negative temperature sensitivity. Considering strain hardening effect, strain rate hardening and thermal softening effect, a modified Johnson-Cook(J-C) constitutive model and a BP artificial neural network(BP-ANN) model are proposed, and the accuracy of the two models is analyzed. The results show that the BP-ANN model can better predict the dynamic mechanical behavior of UFG pure titanium, the correlation coefficient can reach 0.97065, and the average relative error is only 4.63%.

    • Lei Xiaowei, Liu Jia, Yu Wei, Chen Liyang, Ma Zhaowei

      2024,53(2):417-423 DOI: 10.12442/j.issn.1002-185X.20230018

      Abstract:The laser welding processing of 10mm thickness TA5 titanium alloy by using10KW high power fiber laser was syudied. The high speed photography shows that when the laser power reaches 3~4KW, the plume become serious, and the splash and soot increase obviously. The weld metallography test shows that the weld section is "wedge-shaped" when the laser power is low, while the weld section becomes "funnel shaped" when the laser power is more than 6KW.When the laser power is set 10KW~11KW ,and the welding speed is 1100~1500mm/min,an excellent "Key-holding" welding joint is obtained,and the welding seam become typical high-energy beam joint shape with a big ratio of depth to width is up to 2:1. RT and PT test of the weld seam show that NDT standard can be met.The mechanical test shows that the strength of the welded joints can reach 800Mpa, and the bending standard can be met,The fracture dimple is obvious, which indicates a ductile fracture. Metallographic test shows that the section of weld zone is "girdle-shape" morphology and the columnar crystal zones are obvious, with each columnar crystal zone showing obvious competitive growth mode. The weld zone is mainly serrated α+punctate β. The hardness test shows that the hardness of the weld zone is slightly higher than that of base metal, and the hardness of heat-affected zone is the lowest, which meets the hardness requirements of titanium alloy joint.

    • Chen Song, Hunag Sensen, Ma Yingjie, Yang Jie, Wang Qian, Liang Yu, Lei Jiafeng, Yang Rui

      2024,53(2):435-448 DOI: 10.12442/j.issn.1002-185X.20230021

      Abstract:The effects of microstructure and texture on the rotating-bending fatigue anisotropy of an α+β two-phase titanium alloy by β forging was investigated. The microstructure and texture distribution of forged billet in different directions and thicknesses were characterized by OM, SEM, XRD and EBSD, and the effects of microstructure and texture on the rotating-bending fatigue anisotropy were analyzed. The results show that after β forging, the alloy has the characteristics of basket-weave microstructure, the prior β grains are flattened and elongated, and there are recrystallized grains at the grain boundary. The texture of β-phase <100>// axial direction and α-phase <0001>// radial direction formed by forged billet after β forging. The rotarting-bending fatigue strength of radial direction samples is better than that of axial direction samples, which are related to the morphology and texture type of the prior β grains of forged billet. The arrangement of the prior β grains leads to different initiation of cracks and different tortuous degree of crack growth path. In addition, the α and β textures also cause the fatigue strength differences due to the difficulty of slip systems activation of samples in different directions under cyclic loading.

    • Shang Guoqiang, Zhang Xiaoyong, Wang Xinnan, Li Chao, Gan Xueping, Zhu Zhishou, Zhou Kechao

      2024,53(2):529-536 DOI: 10.12442/j.issn.1002-185X.20220993

      Abstract:The effects of three typical microstructures ( bi-modal microstructure, basketweave microstructure and lamellar microstructure ) on the high cycle fatigue properties of TB17 titanium alloy were studied, and the high cycle fatigue fracture morphology was analyzed. The results show that the TB17 titanium alloy with bimodal microstructure has the highest matching level of strength and plasticity, but its fatigue life has a bilinear relationship with stress, and its fatigue performance is not stable. The strength and plasticity of the basketweave structure are slightly worse, but it has the highest fatigue strength and fatigue ratio. The fatigue strength of lamellar structure is slightly lower than that of basketweave structure, but its fatigue ratio and tensile plasticity are the worst. When the high-cycle fatigue loading stress is in a low stress state, fatigue crack prone to inside the specimen, single source initiation, meanwhile, when it is in a high stress state, the fatigue crack tends to be on the surface of the sample and multi-source initiation. There are more secondary cracks in the basketweave microstructure, and the fatigue bands are clearer and denser, the crack propagation path is more tortuous, and more energy is consumed during propagation.

    • >Materials Science
    • Li Jiangtao, Luo Yongjin, Su Zhun, Zhao Zhongwei, Chen Ailiang, Liu Xuheng, He Lihua, Sun Fenglong, Chen Xingyu

      2024,53(2):321-329 DOI: 10.12442/j.issn.1002-185X.E20230018

      Abstract:A novel method to prepare ultrafine WC was proposed: the PbWO4 prepared by hydrothermal synthesis was used as raw material, and WC was obtained through the carbothermic reduction-carburization process. PbWO4 was used as the tungsten intermediate product to avoid the introduction of ammonia nitrogen reagent. The carbon reduction method can avoid the generation of water vapor and inhibit the growth of tungsten powder. Results show that more than 99.9wt% of W is extracted in the form of PbWO4 from the Na2WO4 solution under the conditions of initial pH value of 7.0, reaction temperature of 160 °C, and reaction time of 4.5 h. Then, the homogeneous mixture of W and C is obtained by the carbothermic reduction of PbWO4 at 950 °C for 3 h with the molar ratio of carbon:tungsten as 5. Pre-adding excessive carbon in the mixture can inhibit the agglomeration of tungsten powder. Subsequ-ently, the WC powder with particle size of about 60 nm is obtained by the carburization of the W and C mixture at 1200 °C for 6 h.

    • Zhou Anyang, Huang Yanfei, Guo Weiling, Xing Zhiguo, Wang Haidou, Wang Zhiyuan, Zhang Yanfang

      2024,53(2):330-344 DOI: 10.12442/j.issn.1002-185X.20230341

      Abstract:In order to investigate the influence of different magnetic field strengths on the mechanical property and wear resistance of nickel-based alloy, GH99 nickel-based alloy specimen was subjected to pulsed magnetic treatment by the pulsed strong magnetic field equipment. Through the microstructure observation, the wear mechanism and strengthening mechanism of GH99 nickel-based alloy were analyzed. Results show that the applied pulsed magnetic field improves the material dislocation distribution and reduces the dispersion of residual stress on the specimen surface. At the magnetic field strength of 10 T, the residual compressive stress reaches the maximum value (-223.45 MPa). The tensile fracture of the material is mainly characterized by the ductile fracture. This is because the pulsed magnetic field treatment of the alloy produces sub-structured dislocation cells, which contributes to the fine grain strengthening effect. In addition, the surface microhardness and wear resistance of the specimen are firstly increased and then decreased with increasing the magnetic field strength from 0 T to 15 T. The dislocations inside the alloy proliferate under the pulsed magnetic field, increasing the dislocation density and resulting in the phenomenon similar to the process hardening. However, excessive magnetic field strength may lead to the dislocation plugging, resulting in severe distortion of the cell dot and deterioration of material properties.

    • Liang Wenhui, Wang Yutong, Su Jian, Zhang Ming, Hu Fengxia, Zhang Jian, Liu Yanli, Ren Hanyang, Wang Jing, Shen Baogen

      2024,53(2):345-349 DOI: 10.12442/j.issn.1002-185X.20230415

      Abstract:Amorphous SmCo thin films with thickness of 10–150 nm were deposited on the flexible polyethylene terephthalate (PET) substrates. Tensile/compressive strain was generated in the amorphous SmCo thin film when PET substrate was flattened from concave/convex shape after thin film deposition. Results show that both the normalized remanent magnetization and the squareness of hysteresis loops of SmCo/PET can be tuned by the strain. Compared with that induced by compressive strain, the tunable amplitude induced by tensile strain is larger for the amorphous SmCo thin films. Because the amorphous SmCo thin film has negative magnetostrictive property, the magnetic properties of amorphous SmCo thin film can be controlled by the mechanical strain supplied by flexible substrates. When the negative magnetostriction effect occurs, the magnetization process of amorphous SmCo thin films is hindered by the tensile strain, whereas it is promoted by the compressive strain. The amorphous SmCo/PET shows great potential in the field of flexible spintronic devices and flexible micro-nano electronic devices.

    • Su Jinlong, Luo Cui, Ruan Ye, Qiu Xiaoming, Xing Fei

      2024,53(2):365-370 DOI: 10.12442/j.issn.1002-185X.20230514

      Abstract:Zn-6Sn-5Bi alloy was used to solder DP1180 steel and NdFeB permanent magnet coated with Cu and Ni, and the microstructures and mechanical properties of the soldered joints under different coating conditions were compared and analyzed. Results show that for the soldered joint of sintered NdFeB permanent magnet with Cu coating and DP1180 steel, Cu diffuses in the solder and reacts with Zn and Fe to form brittle intermetallic compounds, resulting in cracks and holes in the soldering seam. The shear strength of the soldered joint of sintered NdFeB permanent magnet with Cu coating and DP1180 steel decreases to 52.3 MPa, compared with that without Cu coating (61.9 MPa). For the soldered joint of sintered NdFeB permanent magnet with Ni coating and DP1180 steel, Ni is concentrated at the interface of NdFeB side, different diffusion layers are formed due to the diffusion of Sn and Bi, and the shear strength of soldered joint increases to 78.1 MPa.

    • Wang Youliang, Liang Bo, Zhang Wenjuan

      2024,53(2):377-385 DOI: 10.12442/j.issn.1002-185X.20230405

      Abstract:The effect of magnetic compound fluid (MCF) slurry on the gallium arsenide (GaAs) wafer surface after nano-precision polishing was investigated. MCF slurry was prepared by mixing CS carbonyl iron particles (CIPs), Al2O3 abrasive particles, α-cellulose, and magnetic fluid. Firstly, a polishing device was assembled by designing MCF unit for the generation of revolving magnetic field. Then, the spot polishing experiments were performed on GaAs wafer surface to clarify the effects of MCF components on the surface roughness Ra and material removal (MR) at different polishing positions. Finally, the scanning polishing experiments were conducted using water-based MCF slurry containing particles with different diameters. Results show that after spot polishing with water-based and oil-based MCFs, the initial surface roughness Ra of 954.07 nm decreases to 1.02 and 20.06 nm, respectively. Additionally, the depth of MR is increased linearly with prolonging the polishing time. It is worth noting that the MR depth of surface after polishing with water-based MCF is 2.5 times higher than that with oil-based MCF. Meanwhile, the cross-section profile of the polished zone shows the W shape, which indicates the non-uniform MR on the workpiece surface after spot polishing. After scanning polishing, the cross-section profile of the polished zone shows the U shape, which indicates that MR is uniform under specific experiment conditions, regardless of the MCF types. The smoothest work surface with Ra=0.82 nm is achieved using MCF with abrasive particles of 0.3 μm in diameter, and MR rate is 13.5 μm/h.

    • Li Suli, Xiong Jie, Gao Zhuang, Ma Kaiyue, Lv Jiawen, Gao Yang, Yang Laixia, Lu Bingheng

      2024,53(2):386-395 DOI: 10.12442/j.issn.1002-185X.20230303

      Abstract:A sliding-pressure additive manufacturing technique with low cost and high accuracy based on Joule heat (SP-JHAM) was developed for the small metal parts. The temperature field and thermal history of the system are important for the experiment analysis. In this research, a thermal-electrical-structural coupling finite element simulation model for three-dimensional SP-JHAM process was established. The temperature field variation law during manufacturing, the temperature distributions inside the wire and substrate, and the shape of isothermal surfaces were analyzed. Results show that the Joule heat is generated between the wire and roller, and the internal temperature of wire rises to 2700 °C within 0.1 s. The position of the maximum temperature is moved with the roller moving. The temperature gradient inside the wire presents the arching shape, and that inside the substrate presents the semi-ellipsoidal shape. The simulated cross-section melting regions are in good agreement with the experimental ones. Thus, the established finite element model can accurately simulate the temperature field of SP-JHAM process, which is of great significance for the guidance of mechanism investigation and actual production.

    • Wen Ke, Li Yongkun, Zhou Rongfeng, Yin Xinhua, Xiong Wentao, Liu Chengxiang, Zhang Yazhen

      2024,53(2):424-434 DOI: 10.12442/j.issn.1002-185X.20230020

      Abstract:The microstructure of materials has an effect on the properties of components. In this study, the effect of deformation on the microstructure and properties of semi-solid CuSn10 alloy was investigated. Semi-solid CuSn10 slurry was made by a self-developed enclosed cooling slope channel (ECSC) and cast into thin plates by rheological squeeze, then rolled at 350°C. The results showed that as deformation increased, casting defects such as shrinkage porosity and shrinkage cavities gradually decreased, with grains compressed and elongated, and their average thickness reduced, from 30.58 μm (undeformed) to 22.12 μm (ε=0.4). In addition, more deformation twins were found inside the primary phase with increasing deformation . As deformation increased from 0 to 0.4, a large amount of substructures and dislocation density was introduced into the CuSn10 alloy microstructure. At ε=0.4, textures [101], [111], and [001] were found in pole figures {110} and {111}. The mechanical properties of the plate, including yield strength, tensile strength, and hardness increased. At the deformation of 0.4, the three properties reached 443 MPa, 554 MPa, and 194 HBW, respectively, up by 106.1%, 66.4%, and 41.6%, compared with those without receiving deformation. But the plasticity of the plate was on the decline, and its elongation decreased to 0.82%. The changes in the alloy are mainly attributed to work hardening and refined grains produced during the rolling deformation.

    • Guo Buju, Xue Zhengduo, Zhang Yuankun, Niu Ziru, Liu Aimin, Li Song, Lei Yizhu, Shi Zhongning

      2024,53(2):449-456 DOI: 10.12442/j.issn.1002-185X.20230029

      Abstract:The lifespan of carbon cathode is affected by the corrosion of molten salt and molten aluminum in aluminum reduction cell, and TiB2 coating is an ideal cathode material for aluminum reduction cells.SIn this paper, TiB2 coatings were electrodeposited on graphite in KF-KCl-K2TiF6-KBF4molten salt at 700-800 oC with the current density of 0.4-0.7A.cm-2. The coatings prepared at different current densities and temperatures were analyzed by XRD, SEM-EDS, surface roughness tester and adhesion tester.SThe results show that the obtained TiB2 coating is uniform and coherent well to the graphite substrate. Increasing the current density and the electrolysis temperature can refine the grain size of the coating and improve the compactness of the coating. A TiB2 coating thickness of 229 μm, the preferred orientation of <110>, the surface roughness of 14.85 μm, and the adhesion between the coating and graphite substrate of 6.39 MPa is prepared by electrodeposition under the optimum condition of 0.6 A.cm-2 and 750 ℃.

    • Sun Zhen, Cui Yun Xin, Zhang Xiong Chao, Zhou Yu Hang, Chen Hao, Xiao Han

      2024,53(2):457-464 DOI: 10.12442/j.issn.1002-185X.20230030

      Abstract:The as-cast CuSn10P1 copper alloy was pre-annealed and then prepared into semi-solid billets by cold rolling isothermal treatment strain-induced melting activation method (CRITSIMA). Using metallographic microscope, scanning electron microscope (SEM) equipped with energy dispersive spectrometer, X-ray diffractometer, electron probe and Brinell hardness tester, the effects of pre-annealing temperature on the microstructure evolution and mechanical properties of semi-solid copper alloy billets were studied. The results show that with the increase of the pre-annealing temperature, the average grain size of the semi-solid copper alloy billet increases, and the shape factor and liquid phase rate decrease; with the increase of the pre-annealing temperature, the solid solution in the α-Cu phase increases with more Sn element, the segregation of Sn element is weakened, the content of intergranular brittle and hard phase δ phase decreases, and the Brinell hardness gradually decreases. The existence of a new phase Cu13.7Sn was detected in the semi-solid copper alloy billet, which is related to the high segregation of the intergranular Sn element. The semi-solid copper alloy billet prepared by pre-annealing at 600 ℃ for 2 h has fine and uniform microstructure and good mechanical properties. The average grain size is 68.34 μm, the shape factor is 0.78, the solid solubility of Sn in α-Cu matrix is 4.21wt%, and the Brinell hardness is 128 HBW.

    • Zhang Yuting, Yang Jing, Yang Zhaolun, Miao Guanghui, Zhang Na, Cui Wanzhao

      2024,53(2):465-473 DOI: 10.12442/j.issn.1002-185X.20230032

      Abstract:Molybdenum has high melting point, low thermal expansion coefficient and excellent stability. It has broad application prospects in plasma propulsion and electric vacuum devices so that its secondary electron emission characteristics have gradually attracted the attention of researchers. Firstly, the secondary electron yield (SEY) and secondary electron spectrum (SES) of molybdenum were studied experimentally. Then the test data were analyzed by the relevant model. Finally, the SEY model of molybdenum is established by Monte Carlo method to analyze the influence of work function on SEY. The results show that the maximum value of SEY is 1.77, which is significantly lower than that of silver-plated aluminum alloy. When the incident electron energy changes, the most probable energy of the true secondary electron peak of the SES is basically unchanged, while the position and intensity of the elastic backscattered electron peak change accordingly. Among all kinds of secondary electrons, true secondary electrons are most affected by the work function.

    • DING Kun-ying, YANG Yi-fei, ZHANG Tao, GUO Wan-sen

      2024,53(2):474-482 DOI: 10.12442/j.issn.1002-185X.20230034

      Abstract:Automatic riveting is an important assembly technology in the aviation manufacturing industry. The distribution of residual stress around the rivet hole after the riveting process is closely related to the fatigue performance of the riveting structure. In this paper, ABAQUS software was used to establish the finite element model of the press riveting process of the 2060-T8 Al-Li alloy plate. It was found that the residual stress on the wall of the rivet hole after the riveting process gradually decreased from the place close to the rivet head to the place close to the rivet head. With the pressure riveting force increasing from 28.5kN to 46kN, the average residual stress of the hole wall of the riveted plate with the rivet material of 2117-T4 increases by 33%, and the uniformity of the residual stress distribution along the thickness of the wall plate increases by 180%. The average residual stress of the hole wall of the riveted plate with 7050-T73 rivet material is increased by 58%, and the uniformity of the residual stress distribution along the thickness of the wall plate is increased by 184%. The fatigue crack originated near the hole wall of the riveted lower plate. With the increase of the riveting force from 32.5kN to 42kN, the fatigue life of the riveted plate with the rivet material of 2117-T4 increased by 31%~80%, and the fatigue life of the riveted plate with the rivet material of 7050-T73 increased by 6%~161%. Compared with the riveted plate with rivet material of 7050-T73, the fatigue life of the riveted plate with rivet material of 2117-T4 under the same process conditions is increased by 12%~44%.

    • zhang chenpei, yang changjiang, Zhao Lvxing, Li Can, Li Qikun, Chang Jun

      2024,53(2):483-489 DOI: 10.12442/j.issn.1002-185X.20230038

      Abstract:In this paper, a rapid and low-cost method was suggested to fabricate carbon nanomaterials-soot particles (CH), and lead/soot (Pb/CH) composite anode materials were prepared by powder metallurgy and mechanical alloying techniques. Oxygen evolution of lead-based anodes was improved due to high activated surface and catalytic activity of carbon nanomaterials. CH was characterized using field emission scanning electron microscopy (FE-SEM), Fourier infrared spectroscopy (FTIR), cyclic voltammetry curve (CV) and linear scanning voltammetry curve (LSV). CH shows a shape of many chains of nanosized with abundant carbonyl and hydroxyl groups as a excellent transfer carrier of electron and proton. The overpotential of composite anodes decreased with the conten of CHin lead/soot materials.The apparent exchange current density of the Pb/1.5 wt.% CH composite anode was increased by 3 and 2 orders of magnitude compared to the pure Pb and conventional Pb/0.75 wt.% Ag anodes, respectively. The oxygen evolving overpotential of Pb/1.5 wt.% CH composite anode was lower than that of the Pb/Ag anode and pure Pb anode by 20 mV and 133mV, respectively, under the simulated zinc electrowinning conditions, showing excellent electrocatalytic activity of oxygen evolution.

    • zhou muhua, zhao congcong

      2024,53(2):490-500 DOI: 10.12442/j.issn.1002-185X.20230040

      Abstract:A thermodynamic coupling finite element model of tungsten selective laser melting was established by using the ‘birth and death element’ technique to simulate the powder laying process, taking into account the material parameter characteristics and latent heat of phase transition. The temperature and stress fields of the forming parts during selective laser melting were simulated. The effects of different preheating temperatures of substrate and different support structures on the residual stress of formed parts was investigated. The simulation results show that tungsten has undergone many heating and cooling processes during selective laser melting, and the temperature distribution is not uniform. Both substrate preheating and applying support structures can reduce the residual stress of the formed part. When the preheating temperature of the substrate is 1273.15K, the residual stress of the intermediate joint of the forming part is reduced by 118.99MPa (9.96%). When the four-layer grid support structure is adopted, the residual stress of the middle joint of the forming part is reduced by 413.33MPa (34.61).

    • Jin Xiaokun, Zhang Shichao, Du Jinfeng, Liang Jun, Song Jianxin, Zhang Zheng

      2024,53(2):501-508 DOI: 10.12442/j.issn.1002-185X.20230041

      Abstract:The microstructure, mechanical properties and fracture mechanism of SP2215 austenitic heat-resistant steel tube after aging at 650 ℃ for different times were studied by OM, SEM, TEM, microhardness, room temperature impact and high temperature tensile tests. The results show that the microstructure of solid solution treated SP2215 steel is composed of austenite, a small amount of twins and undissolved NbN and Z phases. Cr23C6 preferentially precipitates at austenite grain boundaries during aging at 650 ℃, and gradually increases, coarsens and forms a continuous network with the extension of aging time. The spherical Cu-rich phase is precipitated in the austenite grains, when the aging time reaching 2012 h, the size of Cu-rich phase is about 15 nm. The room temperature microhardness in grains of SP2215 steel reaches the maximum value after aging for 50 h, and then tends to be stable, which is related to the precipitation strengthening effect of stable Cu-rich phase. SP2215 steel has obvious tendency of high temperature aging embrittlement. The room temperature impact absorption energy of sample aging for 2012 h is about 78.5 % lower than that of solid solution treated sample. The impact fracture mechanism at room temperature changes from ductile fracture to intergranular brittle fracture with the extension of aging time, which is caused by the precipitation, aggregation and coarsening of Cr23C6 at austenite grain boundary. Portevin-Le Chatelier (PLC) appears when SP2215 steel was stretched with the strain rate of 2.5×10-4 s-1 at 650 ℃, and the serrated type is Type ( A + B ). With the increase of aging time, the PLC gradually “weakens”, but the serrated type remains unchanged. With the extension of aging time, the high temperature tensile yield strength of SP2215 steel remains basically stable, the tensile strength and reduction of area gradually decrease, and the high temperature tensile fracture mechanism changes from ductile fracture to quasi cleavage brittle fracture.

    • MA Dezheng, FAN Qixiang, WANG Tiegang, ZHANG Chao, GONG Jun

      2024,53(2):509-519 DOI: 10.12442/j.issn.1002-185X.20230042

      Abstract:Si-modified NiAl coating has been studied by researchers due to its good performance in high temperature corrosive environment, but the effect of Si content on the high temperature oxidation resistance of the aluminide coatings has seldom studied systematically. To figure out this issue, three modified NiAl coatings with different Si contents were prepared by varying the Si/(Si+Al) ratios eg. 8 wt.%, 17 wt.% and 30 wt.% in the slurry. Phase structures and microstructures of the simple NiAl coatings and three Si-modified NiAl coatings before and after oxidation were analyzed using XRD, SEM and EPMA etc. Results show that the δ-Ni2Al3 and β-NiAl are the primary phases of the four aluminide coatings. Si mainly locates in the upper zone of the Si-modified NiAl coatings in the form of slilicides as CrSi2, Cr5Si3 and Ni2Si. After oxidation at 1000 °C for 500 h, the simple NiAl coating has the maximum weight gain of 1.93 mg/cm2, while the Si-modified NiAl coating with Si/(Si+Al) ratio of 8 wt.% has the smallest weight gain. The dopant of Si into NiAl coatings can promote the formation of protective α-Al2O3 film, retard the outward diffusion of refractory metal elements and improve the surface quality of the oxide film, resulting in reduced oxidation rate. However, the addition of Si reduces the Al content on the surface layer of the coating and may make the Al reservoir β phase insufficient to maintain the selective oxidation of Al in the later period of long-time oxidation. Therefore, when the Si/(Si+Al) is 8 wt.% and the Si content is 9.0 at.%, the Si modified NiAl coating possesses the best oxidation resistance.

    • zhang zhi guo, chen ti jun, zhang xue zheng, wang yan ming

      2024,53(2):520-528 DOI: 10.12442/j.issn.1002-185X.20230053

      Abstract:In this work, an A356 Al alloy based composite reinforced by core-shell structured (CS) particulates was prepared by powder thixoforming, and then further improved the comprehensive mechanical properties of the composite by T6 heat treatment. The results show that the CS particulates not only improved the ultimate tensile strength and yield strength of the composite (increased by 18.0% and 32.7%, respectively), but also rendered the composite an excellent elongation of 12% equivalent to that of the A356 alloy (10.8% and 11.3%, respectively). During the T6 heat treatment, the strength and hardness of the composite increased firstly (1-7h, i.e., under-aging) and then decreased (9-12h, i.e., over-aging) with the extension of the aging time, reaching the maximum value at 8h (i.e., peak aging). The ultimate tensile strength, yield strength and hardness of the composite at peak aging were 325.4 MPa, 254.4 MPa and 104.0 HV, respectively, which were 33.7%, 74.0% and 48.5% higher than those without the heat treatment, and the elongation was 9.4%, which was almost no decrease compared with that without heat treatment. In other words, after the T6 heat treatment, the CS particulates can improve the strength of the composite while retaining its good plasticity. Finally, the strengthening mechanisms of the composite are discussed by analyzing the size, density and type of the precipitates in the matrix of the composites aged for 8h and 12h.

    • Wang Boyu, Guo Xiaolin, Yuan Lin, Li Tianlai, Qiu Tianyi, Fang Qinglong, Wang Xiaojuan, Wang Qi, Liu Yang

      2024,53(2):537-545 DOI: 10.12442/j.issn.1002-185X.20230056

      Abstract:For nuclear radiation n-γ mixed field, a kind of environment-friendly ray flexible synthetic shielding material is developed. The material uses Gd as the core shielding particle and SEBS as the matrix. It has the characteristics of environmental protection, production energy saving, comprehensive protection, flexible plastic, recyclable and so on. Scanning electron microscopy (SEM) shows Gd2O3 powder distributes uniformly in granular form and has excellent dispersion in the matrix. X ray diffraction spectroscopy (XRD) and fourier-transformed infrared spectroscopy (FT-IR) show that Gd2O3 and SEBS are essentially physico-mechanical mixtures, and do not involve changes of chemical bond. The shielding results of γ ray and thermal neutrons show that with the increase of Gd areal density, the transmittances of γ ray and thermal neutrons follow the exponential attenuation law. When the Gd areal density is 0.018 4 ~ 0.291 3 g/cm2, the γ ray transmittances of material at 39 keV, 59 keV and 122 keV are 11.48%~83.73%, 2.73%~75.43% and 51.64%~93.03%, respectively. When Gd areal density is 0.018 9 ~ 0.070 9 g/cm2, the neutron transmittance of material is 35.78%~45.74%. This flexible ray shielding material effectively makes up the disadvantages of traditional shielding materials. It has potential application values in the biological shielding in ships, nuclear medical diagnosis and treatment, radiographic testing and other fields.

    • ZHANG Qiang, WU Rui, LIU Cunfang, ZHANG Hairan, GUO Xiaohua, WANG Junhong

      2024,53(2):546-554 DOI: 10.12442/j.issn.1002-185X.20230060

      Abstract:As a common precious metal, Au nanoparticles (NPs) perform excellent physical and chemical properties. It’s properties are related with the microstructure, morphology and size of Au NPs. The structure and morphology of Au NPs determine their properties. The function and applications depend on properties. In the paper, the properties and applications of Au NPs were briefly introduced firstly, and the method for synthesis of common spherical Au NPs were elucidated. In addition, it is highlighted the versatile morphologies of Au NPs with different function, including rod-shaped, tubular, lamellar, flower-shaped, sea urchin shaped, polyhedron, and core/shell, etc. The approaches for synthesis of the Au NPs with different morphologies and their application were summarized in detail, respectively. Finally, the development of Au NPs in the future was prospected.

    • Nong Xiaoyao, Wang Zhihan, Chen Wenwu, Li Jianwei, Yang Luan, Jin Hao, Lin He, Pan Xifeng

      2024,53(2):555-562 DOI: 10.12442/j.issn.1002-185X.20230731

      Abstract:The traditional Ag sheath has both good chemical compatibility and plastic processing characteristic with iron-based superconductors (IBS), but it possesses too low mechanical strength. Employing composite sheathes is a direct, efficient and low-cost method to prepare high strength Ba1-xKxFe2As2 conductors. In this paper, the Ba1-xKxFe2As2 multifilamentary wires/tapes with stable structure and large ductility were obtained through optimizing the sheath size, cold deformation and intermediate annealing. It is found that the shape distribution of multi-cores is uniform, and the superconducting filling factor is about 25.3-28.0% for our Ag/Nb/Cu composite sheathed Ba1-xKxFe2As2 superconductors. The magnetic critical transition temperature Tc of Ba1-xKxFe2As2 tape is up to 37.5 K, meanwhile the magnetization of hysteresis loops (M-H) shows a strong flux pinning ability. The transport critical current density Jc of Ba1-xKxFe2As2 tape is about 1.0×104 A/cm2 at 4.2 K and 2 T, and still holds 8.7×103 A/cm2 at 10 T.

    • zhenbing, kongweijun, Yubi GAO, wangxingmao, dingyutian

      2024,53(2):563-571 DOI: 10.12442/j.issn.1002-185X.20230428

      Abstract:In this study, the relationship between different medium-temperature deformation heat treatment processes and the microstructure and room-temperature mechanical properties of a novel Ni-based superalloy was investigated using EBSD, SEM and quasi-static room-temperature uniaxial tensile tests. It is shown that the length fraction of annealed twins of the novel Ni-based superalloy can be significantly increased up to 40.6% after the medium temperature deformation heat treatment. The formation of annealed twins is mainly based on the "growth accident" mechanism of the grains. At the same time, compared with the mechanical properties of the solid solution + double-stage aging specimens (σy = 1018 MPa, εf = 17.44 %), the alloy annealed at 1120 °C for 30 min after 30 % roll deformation at 750 °C and double-aged, the σy increased by 499 MPa to 1517 MPa, while the εf decreased by only 4.69 %. After rolling at 750 °C for 50 % of the deformation and annealing at 1120 °C for 30 min with double-stage aging, the σy increases by 352 MPa to 1370 MPa, while the εf remains essentially unchanged. This increase in strength is mainly attributed to the combined effect of grain refinement and annealing twinning, which provides a new strengthening strategy for high performance Ni-based superalloys.

    • >Reviews
    • 董豪鹏, Cai Dingzhou, Su Bin, Liu Kezhao

      2024,53(2):572-580 DOI: 10.12442/j.issn.1002-185X.20230009

      Abstract:Uranium metal and its alloys played important roles in the files of nuclear industry, working as configurational or functional materials. The corrosion behavior of them attracted people"s interest because it would greatly affect the materials" performance. Material factors, including components, microstructures, defects in body and on the surface, were the internal causes to affect the corrosion resistance of uranium materials. This paper conducted a review on how the defects of uranium materials affected their corrosion behavior. We summarized the reported works from four aspects: impurity, inclusions, microstructures and surface states. Strategies to improve the corrosion resistance of uranium materials by means of modulating these defects were also briefly discussed.

    • Luo Lin, Shen Hongxian, Zhang Lunyong, Jiang Sida, Sun Jianfei

      2024,53(2):581-592 DOI: 10.12442/j.issn.1002-185X.20220995

      Abstract:The magnetic refrigeration as a potential alternative refrigeration technique to the conventional vapor-compression techniques is highly regarded for its high energy efficiency and environmental friendliness. The magnetic refrigeration is based on the magnetocaloric effect of magnetocaloric materials which is the critical component of a magnetic refrigerators. The application of the magnetic refrigerators depends on the performance of magnetocaloric materials, among which Mn-Fe-P-Si alloys have been attracting a great deal of attention. Mn-Fe-P-Si alloys are considered to have great promising magnetic refrigerants near room temperature due to their giant magnetocaloric effect, low material cost and tunable magnetocaloric performance. Therefore, this work reviews the recently research progress on the magnetocaloric effect and its performance modulation of Mn-Fe-P-Si alloys in order to provide a reference for the further research on the Mn-Fe-P-Si alloys as magnetic refrigerants.

    • Zhang Jian, Guo Yuanyuan, Zhang Mai, Ye Xinyue, Liu Yi, Liu Yu, Hou Juan

      2024,53(2):593-602 DOI: 10.12442/j.issn.1002-185X.20221002

      Abstract:The single crystal blade laser repair technology reduced considerable cost in the aviation field. This technology is based on the additive manufacturing process, in order to grow an ideal single crystal structure through directional solidification on the single crystal substrate. At present, the mainstream single crystal blade repair technology includes the following two categories: Directed Energy Deposition (DED), Powder Bed Fusion (PBF). In this paper, the research progress of two main repair technologies is reviewed, the influence of process parameters and the mechanism of single crystal growth in the repair process are summarized, and the application potential of single crystal repair technology in the aerospace field is clarified. In addition, this paper also discusses the main challenges currently faced by single crystal blade repair then looks forward to its future development trend.

    • ZHANG Xiangyang, HU Ping, XING Hairui, HE Chaojun, YANG fan, ZHANG Wen, DANG Xiaoming, WANG Kuaishe

      2024,53(2):603-616 DOI: 10.12442/j.issn.1002-185X.20230062

      Abstract:Molybdenum is a refractory metal, which has good high temperature strength, creep resistance, thermal conductivity, corrosion resistance and low sputtering rate. Molybdenum is an important candidate material to meet the development of new generation nuclear energy technology. In the irradiation environment, ion irradiation will change the microstructure of molybdenum metal. This paper reviews the recent studies on the damage behavior of molybdenum metal by irradiation. The effects of different ion irradiation on the microstructure, surface morphology, mechanical properties and optical properties of molybdenum are analyzed. On the basis of the existing research, the future research direction of ion irradiation on the damage behavior of molybdenum metal is prospected, so as to provide reference for the development of metal molybdenum and the application of nuclear reactors.

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    • LU Jiahao, CAI Jili, CAI Chao, SHI Yusheng

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230767

      Abstract:Hot isostatic pressing combined with mold control technology can achieve near-net shaping of complex high-performance components. The mold core is crucial for controlling the internal structural accuracy of the formed parts. Presently, mold cores predominantly employ metallic materials; however, these metallic cores are susceptible to substantial deformation under elevated temperatures and pressures, resulting in compromised precision in shape control. The requisite removal of acid-induced corrosion proves not only inefficient but also environmentally unsound. The diffusion of foreign elements from the metal mold cores results in contamination of parts. Additionally, issues such as embedding of forming powder into the surface lead to poor surface quality of the parts. These problems hinder the development of hot isostatic pressing for forming complex internal cavity structures. Ceramic mold cores, with low chemical reactivity, rapid core removal rate and high temperature hardness, offer a potential solution to issues caused by metal cores. Based on representative literature and research advancements in the field of ceramic mold cores for casting, this paper focuses on analyzing the synergistic relationship between the mechanical and dissolution properties of ceramic mold cores used in hot isostatic pressing. This investigation entails a comprehensive juxtaposition of silicon oxide, aluminum oxide, calcium oxide, and magnesium oxide-based ceramics, elucidating strategies for optimizing mechanical properties, dissolution performance, and moisture resistance. This paper also explores complex high-precision structural formation, sintering, and post-processing methods. Additionally, it anticipates challenges and future directions for the application of ceramic cores in the near-net shaping hot isostatic pressing process. This review aims to offer novel perspectives to experts in the field, accelerating the advancement of hot isostatic pressing technology for complex internal cavity structures.

    • Xie Jing, Teng chengcheng, Sun guodong, Li Hui, Jia Yan, Zhao Peng

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230768

      Abstract:In order to improve the ablative properties of ZrC-SiC ceramics, a series of ZrC-SiC multiphase ceramics modified with different contents of La2O3 and LaB6 were prepared by discharge plasma sintering method at 1600 ℃/50 Mpa. The ablative properties of the materials were tested under an oxy-acetyl flame with a heat flux of 2380 kW/m2. The results show that the addition of La2O3 and LaB6 not only improves the sintering performance and density of ZrC-SiC, but also improves the thermal shock resistance. With the increase of the addition amount, the surface oxide layer of the sample gradually becomes complete after ablation. In contrast, the ZrO2-La2Zr2O7 solid solution layer formed on the ablative surface after La2O3 modification still has more holes and cracks, and the combination with the internal ceramics is poor, resulting in the poor protection effect. With the addition of LaB6, the volatilization of low melting point borides during ablative process can reduce the ablative temperature of the material by nearly 300 ℃. La2Zr2O7-LaBO3-ZrO2 outer oxide layer with good thermal stability and lanthanum-rich Zr-O-La-B inner oxide layer with good adhesion are formed on the surface of the ablation center of the sample. The double-layer protective film becomes a dense barrier to prevent the oxidation air from entering the inside of the material, and effectively improves the ablation resistance of the material. The ZrC-SiC with 20 vol.% LaB6 has the best comprehensive ablative performance, oxygen acetylene ablative for 60 s, and its mass and linear ablative rate are 0.5×10-4 g/s and 2.1×10-3 mm/s, respectively.

    • wang wan nian, cao guo xin, zhu xu, chen zhan xing, wang xiao hong, xing qiu wei, ma tengfei, fu bao quan

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230771

      Abstract:The influence of various heat treatment temperatures on the microstructural evolution and mechanical properties of the cold-rolled Ni42W10Co1Mo alloy was studied. The results indicated that the TCP phases transformed from σ phase to μ phase with the increase of heat treatment temperatures, and then transformed from μ phase to σ phase finnaly. The microstructure evolved from deformed dendrites to a uniform equiaxed grains. After heat treatment at 900°C, the precipitation phases are predominantly needle-like and blocky μ phases, with a small quantity of granular μ phases. Recrystallization was also evident. After heat treatment at 1200°C, a substantial amount of granular σ phases precipitated accompanying the completion of recrystallization. The extensive precipitation of TCP phases consumed a large amount of W element leading to a decrease of solid solution strengthening. The room temperature yield strength was decreased from 1564 MPa to 479 MPa after heat treatment at 1200°C, while, the elongation was enhanced to 72.4%. The precipitation of larger-sized μ phases was adversely to ductility, in contrast to the smaller-sized σ phases impeded crack propagation and enhcaned the ductility.

    • Wei Zhuang, Gao Min, Duan Jingbo, Shi Dongmei, Zhang Yuling, Li Chen

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230772

      Abstract:To investigate microstructural damage of porous W/Zr-based metallic glass composite. The microscopic-scale finite element model of the composite was established based on the scanning electron microscope (SEM) images of porous W/Zr-based metallic glass composite, and the quasi-static compression process of the composite was numerically simulated in conjunction with the cohesive zone model. The effects of interface stiffness, interface strength and fracture energy on the mechanical properties of the composite were investigated, and the values of the cohesive zone model parameters were determined by comparing them with quasi-static compression experimental data. It was found that three damage modes occured in the composite during compression, which were cleavage fracture of the W-particle, shear band fracture within the Zr-based metallic glass and interfacial crack between the two phases. The cohesive zone model parameters have a great influence on the simulation curve: the greater interface stiffness, the higher slope of the simulation curve; the greater interface strength, the higher yield point of the simulation curve; the larger fracture energy, the shorter plastic phase of the simulation curve. As the interface stiffness, interface strength, and fracture energy were taken as 10000 GPa/μm3, 500 MPa and 0.055 J/m2, respectively, the simulation results were well consistent with the experimental results, and the simulation model was able to accurately describe the mechanical behaviors of porous W/Zr-based metallic glass composite.

    • mengyichen, chuyinrun, shiyuelin, liuxiaomei, wangliang, zhangqunli, yaojianhua

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230774

      Abstract:High entropy alloys, as a new type of structural alloy, are expected to achieve breakthrough applications in the field of laser additive manufacturing. This article uses laser cladding technology to prepare a high entropy alloy coating on the surface of 38CrMoAl. The effects of adding elements such as Al, Si, Fe, Nb to CoCrNi series alloys on the phase, microstructure, and element distribution of the alloy coating are studied, and the hardness, wear resistance, and corrosion resistance of the coating are analyzed and characterized. The results indicate that CoCrNi alloy has a face centered cubic (FCC) crystal structure, and the addition of Al and Fe promotes the formation of body centered cubic (BCC) phase; After the addition of Nb and Si elements, a Laves/BCC eutectic+Nb riched composite phase was formed in the seven-element-alloy coating, and the microstructure was significantly refined. The comprehensive performance of CoCrNi based high entropy alloy coatings is superior to that of 38CrMoAl substrate. Compared to CoCrNi and AlCoCrFeNi alloy coatings, the hardness, wear resistance, and corrosion resistance of AlCoCrFeNiSiNb coatings have significantly improved: the surface hardness is 713.3HV0.1, which is 3.24 times higher than that of the substrate; the wear mechanism is mainly slight abrasive wear and adhesive wear, with an average friction coefficient of 0.5 and a wear rate of 77.15 × 10-3mm3/(N ? m), reduced by 76.3% compared to the substrate; self corrosion potential (Ecorr) is -0.3392V, and self corrosion current density (icorr) is 0.472 μ A ? cm-2.

    • Zitong Wang, Di Dong, Ning Xiong, Jiawei Xu, Zhi Dong, Zongqing Ma

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230778

      Abstract:In order to produce economical tungsten alloys with superior mechanical properties, 93W-4.6Ni-2.4Fe (wt.%) tungsten heavy alloys were fabricated by ball milling (BM) and liquid phase sintering (LPS) at a temperature range of 1450-1510°C. The microstructure and the fracture modes of the specimens were further examined. The specimens sintered at different temperatures display similar dul-phase microstructure and ductile fracture modes. With the increase of the sintering temperature, the tungsten particle size also gradually grows. At and above the temperature of 1480°C, the relative density reaches above 99.0%. The optimal sintering temperature of the specimen with the best tensile strength (940 MPa) and elongation (32.6%) combination is determined to be 1480°C. The excellent ductility of the specimen sintered at 1480°C is associated with the network structure of γ phase, the uniform distribution of dimples and the synergistic effect of these two phases. The high strength of the specimen is attributed to the refined tungsten particle size and the spherical tungsten particles.

    • Chen Tao, Liu Chunjiao, Wu Zhigang

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230779

      Abstract:In order to analyze the carburizing resistance of Fe-Cr-Ni alloy cracking furnace tube, carburizing test about two kinds of traditional furnace tubes 25Cr35NiNb+MA, 35Cr45NiNb+MA and two kinds of aluminum alloy 27Cr44Ni5W3Al+MA, 29Cr44Ni4Al+MA furnace tubes with prolonged coke cleaning period was carried out at 1075℃ for 50~200h. The test was prepared with solid carburizing agent with particle size of 1.5~3mm. The composition, microstructure and properties of the furnace tubes after carburizing test were analyzed by optical emission spectrometer, scanning electron microscope, X-ray diffraction instrument and Vickers hardness tester, and the carburizing kinetics and microstructure transformation rules were studied. The results showed that: The thickness of the carburized layer of the four kinds of materials increased with the extension of carburizing time. After carburized at 1075℃ for 200h, the thickness of the carburized layer of the furnace tubes was about 2mm, 1.8mm, 1mm and 0.7mm, respectively, and the average carburizing rate was about 0.01mm/h, 0.009mm/h, 0.005mm/h and 0.0035mm/h, respectively. The carburizing resistance of the two aluminum alloy tubes was better than that of the traditional tubes. The microstructure in the aged zone of 27Cr44Ni5W3Al+MA furnace tube was composed of austenite, blocky M23C6 and fishbone M7C3, and the "M" of carbides contained Cr, W and other elements. In the carburized zone, blocky M23C6 was transformed into blocky M7C3 and WC, and fishbone M7C3 was coarsened. The microstructure in the aged zone of 29Cr44Ni4Al+MA furnace tube was composed of austenite austenite, blocky M23C6 and NbTiC, the "M" in carbides was mainly Cr element, the blocky M23C6 in carburized zone was transformed into blocky M7C3, and the blocky NbTiC was transformed into granular. The effects of Cr2O3 and Al2O3 layer on the carburizing resistance of furnace tubes were also discussed.

    • Yu Jianshi, Yuan Yingbo, Li Zhenyang, Huang Gang, Liu Xiaofang

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230780

      Abstract:ZrCo alloy has been initially applied in nuclear fusion experimental reactor due to its high hydrogen isotope storage capacity, low equilibrium pressure at room temperature and no radioactivity. However, ZrCo alloy has some issues, such as long activation time, poor kinetic properties and severe disproportionation, which restrict its engineering process. Therefore, it is of great significance to improve the hydrogen storage performance of ZrCo alloy and realize the synchronous improvement of dynamic characteristics, cycle stability and anti-disproportionation performance, which is crucial for revealing hydrogen storage mechanism of ZrCo alloy and promoting its engineering application. The development of high-performance ZrCo-based isotope hydrogen storage alloys is the bottleneck to realize the application of nuclear fusion reactors. Recent studies have validated that nano ZrCo-based hydrogen isotope storage alloys can significantly improve its activation performance, hydrogen absorption kinetics, anti-disproportionation performance and cycle stability. In this paper, the latest research trends of nanostructured ZrCo alloys are systematically summarized, and the mechanism of nanostructure on improving hydrogen storage performance is emphatically elaborated. The future research and application prospects of nanostructured ZrCo-based hydrogen isotope storage alloys are prospected.

    • Wang Liang, Hu Yiwen, Zhou Peishan, Wang Bin, Zheng Hualin

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230782

      Abstract:The effects of alloying elements on the phase precipitation behavior of a new high-boron Ni-based superalloy were studied using JMatPro thermodynamic software, and compared with the actual casting microstructure. The results indicate that the as-cast microstructure of the new high-boron Ni-based superalloy exhibits a typical dendritic morphology, mainly composed of γ、γ"、carbides, borides, and(γ+γ") eutectic (fraction of about 15.5%), The segregation of Hf and Ta elements is obvious during the solidification process. Thermodynamic calculations indicate that the elements that significantly impact the melting temperature of alloys are Ti, Ta, Hf, B, and Al. The initial precipitation temperature of the γ" phase and its precipitation amount at 900 ℃ increase with Al content, while the influence of Ti element is relatively small. In addition, the provision of Ta and Hf element content will promote the precipitation of MC-type carbide, and the influence of Cr element on the precipitation amount of M23C6 carbide is greater than that of M6C carbide. The precipitation of borides is mainly influenced by Cr and W elements, while Mo element has a significant impact on the precipitation temperature of M3B2 borides. As the content of Co, Cr, W, and Mo elements increases, The amount of the μ phase and precipitation temperature both show an increasing trend.

    • Kou Wenjuan, Yin Yanfei, Zhou Feng, Shi Zhaohui, Zhao Yongqing

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230783

      Abstract:In this paper, the laminated Ti /Ti-50 Nb composites with diffusion layers was designed and fabricated by spark plasma sintering (SPS) combined with hot rolling. In-situ tensile tests monitored by SEM were applied to analyze the crack initiation and propagation of the composites, so as to understand the effects of the thickness of Ti components and the microstructure of the diffusion layer on the fracture behavior of the composites. The results indicated that by reducing the thickness of Ti component, the length of microcracks could be effectively controlled, thus delaying the extension of shear bands in adjacent TiNb layers. The microstructure of the diffusion layer had a significant effect on the fracture behavior of the composite. Compared with the composite with the "hard" diffusion layer, there were more cracks and shear bands before tensile fracture, and a more tortuous crack growth path after the overall fractured in the composite with the "soft" diffusion layer.

    • Zhou Yuecong, Ouyang Sheng, Deng Cuizhen, Long Jian

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230736

      Abstract:Brittleness of traditional Ni-Mn-Ga alloy is a big obstacle for its practical applications, as actuators and sensors. The Ni-rich Ni-Mn-Ga alloy can significantly improve the ductility. However, the shape memory strain is largely reduced. Higher martensitic transformation temperature, good thermal stability and moderate shape memory property are shown in Mn-rich Ni-Mn-Ga. In the present work, microstructural feature, mechanical performance and thermal property of Ni54Mn28 +xGa22-x (x = 0, 4, 7, 9, 13) were investigated. As the Mn content increases, the γ phase appears, it is a face centered tetragonal (FCT) structure, and a γ grain contains a hierarchical “nano-lamellae forming within micro-lamellae” microstructure. A micro-lamella consists of two variants, each variant has a pair of nano-lamellae, and they are {0 1 1} twin related. Owing to the introduction of lamellar γ, the ductility is improved. With increase of Mn content, the compressive stress increases from 914 MPa to 2175 MPa, the compressive strain increases from 14 % to 26 %. The martensitic transformation temperature of such series of alloys increases from 352 °C to 585 °C. For Mn-rich Ni-Mn-Ga alloy, the ductility improvement is inferior to that of Ni-rich alloy, but the martensitic transformation temperature is higher.

    • Yang Xiaohong, Liu Zixian, Li Xuejian, Xiao Peng, Liang Shuhua

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230737

      Abstract:CuW/CuCr integral materials containing Cu-Cr-Zr powder interlayer was prepared by integral sintering infiltration method. The effects of Cr and Zr content and solution aging heat treatment on the microstructure and properties of the interface and both sides of the material were studied. The results show that with the increase of Zr in Cu-15%Cr-X%Zr interlayer, the eutectic phase on CuCr side of the whole material increases, and the conductivity at CuCr end decreases. The hardness increases first and then decreases. At the same time, the addition of Zr promotes the diffusion of Cr into W. The tensile test bars of integral materials with different composition interlayers were prepared, and the interfacial tensile strength was tested and the fracture morphology was analyzed. It is found that when the Zr content in the interlayer is 0.5%, the interfacial tensile strength of the whole material reaches the maximum value of 517MPa, which is 18% higher than that of the CuW/CuCr whole material with Cu-15%Cr interlayer without Zr. The tearing edge of Cu phase in the tensile fracture becomes shallower and shorter, and the number of cleavage fractures of W particles increases, which indicates that the interfacial strength of Cu/W phase and the end strength of CuCr are improved.

    • Jinchao Du, Xiaofei Li, Peiying Jiao, Zhiguang Zhang, Pei Gong

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230739

      Abstract:Several experiments have shown that adding a fractional amount of Al can increase the elongation of the alloys and without the significant reduction of the magnetostrictive strain for Fe-Ga alloys. Furthermore, since the price of Al is lower than that of Ga, using Al to replace part of Ga in the (Fe73Ga27)99.8Tb0.2 alloy saves production costs as well. The (Fe73Ga27-xAlx)99.8Tb0.2(x=0,1,2,3,4,5) alloys were prepared by vacuum arc furnace to study effect of Al addition on the microstructure, magnetic properties and mechanical properties of. The results show that the phase structure of the alloys is still A2 phase and Tb2Fe17 phase, and the metallographic structure is composed of cellular crystal and columnar dendrite. The decrease of lattice constant, the increase of (100) orientation and the generating of Tb2Fe17 at the grain boundary saliently exert effect on the magnetostrictive properties. The fracture morphology of the alloys is intergranular brittle fracture and cleavage fracture, the causes of fracture including segregation of Tb and Al elements. The parallel magnetostrictive strain (λ) of (Fe73Ga24Al3)99.8Tb0.2 alloy reaches 104 ppm. It is worth noting that compared with (Fe73Ga27)99.8Tb0.2 alloy, the λand elongation of (Fe73Ga25Al1)99.8Tb0.2 alloy increase by 18.3% and 53.4% particularly, which also possesses the characteristics of high saturation magnetization (Ms), low remanent magnetization (Mr) and coercivity (Hc), thus cutting the cost in actual production while the tensile strength and Vickers hardness exhibit a slight descending trend. Therefore, it is important to study the micro-mechanism of Al addition on Fe-Ga alloys for the development of Fe-Ga alloys devices.

    • zhang xiao, wang kuaishe, niu shuai, ren baojiang, liu xuyang

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230740

      Abstract:Ammonium molybdate with lanthanum was prepared by centrifugaldrying, which was calcined to molybdenum trioxide with Lanthanum. The thermal decomposition of ammonium molybdate with lanthanum inairwasanalyzed by XRD and TG-MS, and the morphology and physicochemical properties of molybdenum trioxide with lanthanum were studied at different calcinationstemperature.The result shows that the structure of molybdenum trioxide with lanthanum is amorphous and microspheres withhollowspace inside. There were three stages in the process of the thermal decomposition of ammonium molybdate with lanthanum. Firstly, the centrifugaldrying powder changed from amorphous to crystalline states due to heat-treatment from room temperature to 196.5℃. Secondly, the residual ammonia ion in ammonium molybdate was decomposed from 196.5℃ to 337.8℃, and metastable molybdenum trioxide was formed, finally, metastable β-MoO3 turned into α-MoO3 from 337.8 ℃ to 410.1℃. Molybdenum trioxide with lanthanum prepared at different calcinedtemperature inherited the morphology of centrifugaldrying powder, with the increase of temperature, the surface of powder was coarser and thebreakageofpowder wasseriouser, and the internal small particles of powder changed from irregular and bonded to relatively regular flake. The change of calcinedtemperature had little effect on thecontentsof theimpurityelements in molybdenum trioxide with lanthanum, but with the increasing of calcinedtemperature, the apparent density and particle size reduced slightly.

    • Ran xing

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230742

      Abstract:In order to improve the metallurgical quality of large titanium alloy castings by vertical centrifugal casting, the mold flow analysis method was used to explore the influence of linear and spiral runner systems on the melt filling flow state. The results indicated that there is a phenomenon of melt adhering to the wall distribution in traditional linear runners, and reducing the cross-sectional size of the runner cannot avoid the formation of the suction zone in the transverse runner cavity. In addition, the melt accumulation and backflow exhibited in the transverse runner, and the melt in the filled casting cavity was in a jet flow state. Based on the D"Alembert"s principle, the motion behavior of melt particles in the two-dimensional plane of the runner was analyzed, revealing that the main reason for the above problem is the mismatch between the particle motion trajectory and the linear runner structure. Further exploration was conducted on the effects of centrifugal speed and initial particle velocity on the shape characteristics of trajectory lines. A design method for a spiral shaped runner gating system suitable for large annular titanium alloy castings was proposed. The mold flow analysis results verified that the spiral shaped runner can effectively reduce suction and turbulence tendencies, balance the casting filling flow field, and form a bottom-up filling sequence.

    • Shao Peng, Chen Xuan, Huang Sheng, Yu Kun, Chen Hao, Liu Kun, Xiao Han

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230745

      Abstract:The Cu-Ti composites were prepared by liquid-solid composite process, and the diffusion behavior of Cu and Ti elements at the composite interface was investigated with the help of optical microscope (OM), scanning electron microscope (SEM), electron probe (EPMA) and other testing methods. The results show that the grain boundaries are the main channels for diffusion in the process of Cu/Ti composite. Except for part of the Cu4Ti phase formed on the Cu matrix, the rest of the compound phases of the diffusively dissolved phase layer were generated on the Ti matrix. The compounds generated at the copper-titanium composite interface are Cu4Ti, Cu3Ti2, CuTi, CuTi2, where the Cu3Ti2 phase grows in a "jagged" manner, the CuTi phase grows in a "bamboo shoot" manner, and the CuTi2 phase grows in a "planar" manner. The hardness values of the diffusion-dissolved layer are significantly higher than those of the two pure components. As verified by the Miedema model, the sequence of interfacial phase precipitation is CuTi, Cu3Ti2, CuTi2, Cu4Ti. The bonding of copper and titanium is a result of the joint action of copper diffusion in titanium and titanium dissolution in the copper solution.

    • Yang Yan, Han Xinyang, Qiu Yuxia, Lin Bin, Chen Junfeng, Chen Yulong, Chen Shujian, Zou Linchi, Chi Haitao, Zhang Wei

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230757

      Abstract:In this paper, highly wear-resistant GNPs/AlSi10Mg composites were prepared by surface modification of graphene nanoparticles (GNPs) with ethyl cellulose (EC), combined with solution ultrasonic dispersion and wet ball milling to achieve both uniform mixing of GNPs and aluminum matrix and inhibition of damage to the GNPs, and then suppression of the interfacial reaction by rapid sintering with discharge plasma. In this study, the microstructure and wear-resistant properties of GNPs/AlSi10Mg composites were characterized and analyzed by scanning electron microscope, transmission electron microscope and friction tester, etc. The results show that the moderate addition of GNPs can effectively improve the mechanical properties of the composites, and the wear rate and friction coefficient of the composites are lowest when the amount of GNPs added is 0.5 wt.%, which are respectively 7.8×10-4 mm3/Nm and 0.417, and the wear rate was reduced by 28.4% compared with that of the matrix material (10.9×10-4 mm3/Nm).The wear mechanism of the GPNs/AlSi10Mg composites was dominated by abrasive wear accompanied by slight oxidative wear and adhesive wear. The composite specimen in contact with the dyad during the friction process forms a thin film on the exposed surface of the GNPs under the action of shear force, which can be used as a lubricant to reduce the contact point between the dyad and the matrix, preventing excessive spalling and delamination, and playing a role in the protection of the matrix.

    • Yang Bin, Bai Wenbo, Zheng Yang, Yu Chao, Xiao Hong

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230758

      Abstract:The effect of different surface treatments on the bonding strength of composite plates was investigated at 400°C and 45% reduction rate. The wire brush grinding treatment can only eliminate the oxide film on the plate surface, hardly produce a hard layer on the plate surface, and the bonding effect depends on the diffusion of elements generated by the close contact between the metals on both sides of the interface. After anodic oxidation, there is a hard layer on the metal surface, and the broken hard layer during the rolling process forms a mechanical occlusion at the bonding interface. However, the hard layer cannot form an effective combination with the metal at the interface, and the bonding can only occur in the fresh metal bonding area at the crack of the hard layer. The acid-alkali washing treatment can completely remove the hard layer on the surface of both alloys. Meanwhile, it will not increase the surface roughness of the plate, and the metal on both sides of the interface is more closely bonded during the rolling process. The best bonding strength can be obtained by using acid-alkali washing as the surface treatment for aluminum-magnesium hot-rolled bonding..

    • Zhang Jin, Zhang Conghui, Wang Yanfeng, Zhu Wenguang, Liu Lintao

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230764

      Abstract:Zirconium alloy coating can improve the accident resistance of zirconium alloy cladding without changing the present fuel system, which is one of the hot research directions to improve the accident tolerant ability of nuclear fuel assemblies. Cr-based coating is the most widely concerned coating material at the current stage. The design ideas and development progress from Cr coatings to various Cr-based coatings after Fukushima nuclear accident are systematically reviewed in this paper. The selection basis and high temperature oxidation failure mechanism of Cr-based coating is introduced. The solution ideas and research progress are discussed from two aspects of composition and structure designs. Finally, the development prospect of Cr-based coating of zirconium alloy in the future is proposed. The review has important reference significance for the development and application of the new generation of ATF coating technology in the future.

    • Cui Liya, Wang Changji, Zhao Ziwen, Pan Kunming, Zhao Longze, Ren Yongpeng, Cui Hailin

      Available online:March 15, 2024  DOI: 10.12442/j.issn.1002-185X.20230766

      Abstract:Tungsten and it’s alloys not only have the advantages of high melting point, high density and excellent resistance to plasma sputtering erosion, but also have excellent comprehensive mechanical properties in the high-temperature service environment, which is the indispensable key of material for aerospace, weapons and equipment, nuclear engineering and so on. However, tungsten alloy faces the problem of large scale and uneven distribution of strengthening phase in the extreme high temperature service environment that resulting in insufficient high temperature strength and toughness. In order to solve the above problems, domestic and foreign scholars have carried out research on the strength and toughness of tungsten alloy, and improved the mechanical properties of tungsten alloy by adjusting the material composition and microstructure. In this paper, the structure control and toughening mechanism of tungsten alloy are discussed from three aspects: deformation strengthening, solution strengthening and dispersion strengthening, and the future development trend and unsolved problems of tungsten alloy are prospected.

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    Latest number
    Rare Metal Materials and Engineering
    2024,Volume 53, Issue 2
    Editor in chiefPingxiang Zhang
    Associate editorYingjiang Shi
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