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    2024,Volume 53, Issue 5

      >Special Issue:refractory metal
    • Wang Zitong, Dong Di, Xiong Ning, Xu Jiawei, Dong Zhi, Ma Zongqing

      2024,53(5):1229-1235 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 and liquid phase sintering at a temperature range of 1450?1510 °C. The microstructure and the fracture modes of the specimens were examined. Results show that the specimens sintered at different temperatures display similar dual-phase microstructure and ductile fracture modes. With the increase in sintering temperature, the tungsten particle size also gradually grows. At the temperatures above 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.

    • Liu Meijun, Xu Liujie, Li Zhou, Guo Mingyi, Hu Jikang, Shen Huahai

      2024,53(5):1236-1244 DOI: 10.12442/j.issn.1002-185X.E20230049

      Abstract:A new refractory high entropy alloy WMoNbTaV containing Al2O3 was prepared by spark plasma sintering. The effects of sintering temperature on densification behavior, phase structure, microstructure and wear resistance of the alloy were studied. The results show that when sintered at 1800?1900 °C, the matrix of WMoNbTaV-Al2O3 has a single bcc phase structure, and the average grain size of Al2O3 is 1.15 μm. With the increase in sintering temperature, the grain size of the alloy increases, the density and microhardness also increase, and the hardness reaches 7967.4 MPa when the sintering temperature is 1900 °C. The alloy sintered at 1900 °C has excellent wear resistance, and the wear amount is only half of that of the alloy sintered at 1800 °C. The wear resistance of WMoNbTaV-Al2O3 high entropy alloy is much higher than that of pure W material. When the abrasive particle size is 37.5 μm, the wear mass loss of alloy sintered at 1900 °C is 0.9 mg, and the wear resistance of alloy is 83 times higher than that of pure W material.

    • Luo Chunyang, Xu Liujie, Shen Huahai, Li Xiuqing, Wei Shizhong

      2024,53(5):1245-1251 DOI: 10.12442/j.issn.1002-185X.20230777

      Abstract:Dispersion strengthening plays an important role in improving the properties of alloys. The stability of carbide and oxide ceramics, as commonly used dispersion-reinforced particles, is important for alloys applied in nuclear reactors serving in harsh environments, so it is of great significance to study the radiation resistance of SiC, TiC, ZrC, Al2O3, Y2O3 and ZrO2. The effects of different energies and different types of incident ions on different materials were simulated by SRIM program, and the irradiation damage of zirconia at different irradiation doses was analyzed. Results show that with the increase in incident ion energy, the distribution of the incident ions in the target material tends to be uniform and normal, and the stop position of the incident ions and the damage depth of the target material increase. The damage to the target material is different under different types of incident ion, which is not conducive to the radiation resistance comparison of the materials. Under the same irradiation conditions, the distribution of incident ions is consistent regardless of the increase in irradiation dose, but irradiation damage is accumulated until saturation. Among these six substances, zirconium oxide and zirconium carbide have better radiation resistance. The irradiation properties of zirconium oxide were verified by carbon ion irradiation experiments for tungsten alloy reinforced by zirconium oxide at 700 °C.

    • Wang Hui, Ding Chenshi, Xie Zhuoming, Liu Rui, Fang Qianfeng, Wang Xianping, Liu Changsong, Wu Xuebang

      2024,53(5):1321-1331 DOI: 10.12442/j.issn.1002-185X.20230729

      Abstract:Four kinds of tungsten-based materials, W-0.5 wt.%ZrC-(1, 3) wt.%Re (WZC1R, WZC3R) and W-0.5 wt.%HfC-(1, 3) wt.%Re (WHC1R, WHC3R), were prepared by mechanical ball milling and spark plasma sintering (SPS). The microstructures, mechanical properties and thermal stability were investigated. The WZC3R alloy exhibits a high ultimate tensile strength (UTS) of 728 MPa at 500 °C and an UTS of 653 MPa at 600 °C, respectively, which are about 2.1 times higher than SPSed pure W. The uniformly distributed nano-sized ZrC and HfC particles can pin the grain boundaries and dislocations, thereby increasing the strength and inhibiting grain coarsing. The WHC3R exhibits a total elongation (TE) of 13.9% at 400 °C, and its DBTT is in the range of 300 ~ 400 °C, which is about 200 and 300 °C lower than that of SPSed W-ZrC and pure W, respectively. The addition of the solid solution element Re improves the toughness of W materials by increasing the number of available slip planes and reducing the critical stress needed to start plastic deformation. In addition, the four alloys show excellent high-temperature stability with no significant change in grain size and Vickers microhardness even after heat treatments at temperatures reach up to 1600 °C. The Re element solidly dissolved in W leads to lattice distortion, which can inhibit the diffusion of W atoms at high temperatures, hinder the migration of grain boundary, and slow down the kinetic process of W grain coarsening, thus enhancing the high-temperature stability of the W materials.

    • Zhu Lian, Yuan Weichao, Hu Shuangpeng, Wang Zhen, Ye Yicong, Bai Shuxin

      2024,53(5):1332-1342 DOI: 10.12442/j.issn.1002-185X.20230682

      Abstract:Niobium (Nb) is widely used in aerospace, nuclear energy and superconducting fields, due to its excellent comprehensive physical and chemical properties. In the preparation methods of the Nb coating, the molten salt electrodeposition technology has fast deposition rate, high cathode current efficiency and is suitable for complex shape components, which is expected to realize large-scale industrialized production and application. Since the current widely used fluoride-supported electrolyte system is highly toxic and environmentally unfavorable, there is an urgent need to carry out the development of a more environmentally friendly all chloride supporting electrolyte system. To achieve the regulation of the molten salt’s physical properties of the supporting electrolyte and the stabilization of the complexing ions, this study adds CsCl to the NaCl-KCl system to prepare an all chloride supporting electrolyte system and investigates the effect of CsCl on the molten salt’s physical properties of the supporting electrolyte and the electrodeposition behavior of the Nb coating. The results showed that the eutectic temperature of the NaCl-KCl-CsCl ternary mixed molten salt was about 485 °C. With the increase of CsCl content, the initial crystallization temperature of molten salt decreased at first and then increased, the density increased, and the conductivity and surface tension decreased. CsCl affected the mass transfer rate of ions in molten salt by changing the initial crystal temperature and conductivity of molten salt, and then affected the surface quality of electrodeposited Nb coating, and its preferred content was about 60 wt.%. The addition of CsCl can make the reduction potential of the oxygen-containing complex ion NbOF63- in the molten salt negative to that of NbF72-, which was helpful to obtain Nb coatings without oxygen impurities.

    • YANG Junzhou, Wang Shichen, WANG Xianjun, WANG Zhixuan, WANG Li, XING Hairui, HU Boliang, Gao Xuanqiao, Zhang Wen, HU Ping, WANG Kuaishe

      2024,53(5):1343-1348 DOI: 10.12442/j.issn.1002-185X.20230734

      Abstract:In order to study the flow behavior of Mo-14Re molybdenum-rhenium alloy at high temperature and its cross-scale characterization, the high temperature compression test of molybdenum-rhenium alloy bar was carried out with Gleeble thermal simulation testing machine, and the selected temperatures were 1400 ℃, 1500 ℃ and 1600 ℃. The strain rates are 0.01 /s, 0.1 /s, 1 /s and 10 /s. The results show that when the strain rate sensitivity factor increases gradually, the plastic flow performance of the material will be better, and the two phenomena of stress hardening and softening exist simultaneously during deformation. On this basis, a cross-scale constitutive model is established. The flow stress characterization takes into account the resistance, thermal activation and grain boundary effects of the immobile dislocation. The microstructure evolution takes into account the grain size, dislocation density, dynamic recrystallization rate and crack volume fraction. The calculated values of yield stress, grain size and flow stress are in good agreement with the experimental results. It can be seen that the model can describe the rheological behavior and microstructure evolution of Mo-14Re molybdenum-rhenium alloy during high temperature deformation.

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

      2024,53(5):1349-1354 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.

    • Wang Guangda, Ren Xueting, Xiong Ning, Kuang Chunjiang

      2024,53(5):1355-1362 DOI: 10.12442/j.issn.1002-185X.20230648

      Abstract:Molybdenum rhenium alloy has excellent mechanical and machining properties, and is a key structural material in fields such as electronics and nuclear industry. Adding zirconia to molybdenum rhenium alloy forms dispersion strengthening effect, and combined with deformation strengthening to improve the mechanical properties of the material. Research has found that the particle size of alloy powder decreases with the increase of ZrO2 content, with the smallest and most uniform grain size at a content of 0.7%; ZrO2 particles exhibit a pinning effect during the deformation and fracture process of the alloy, significantly improving its mechanical properties such as tensile strength, yield strength, and elongation after fracture. The tensile strength and elongation after fracture of ZrO2 strengthened molybdenum rhenium alloy reach the highest value when the ZrO2 content is 0.7%, and then decrease; ZrO2 is basically dispersed at grain boundaries and forms a good bonding interface with the molybdenum matrix, which can inhibit the migration of grain boundaries and improve the deformation resistance of molybdenum alloys.

    • Wang Xin, Liu Xingwei, Liu Tianyu, Wang Ling, Li Shukui, Xiong Ning, Liu Jinxu

      2024,53(5):1363-1370 DOI: 10.12442/j.issn.1002-185X.20230154

      Abstract::In this paper, the exploration and research of W-Ce alloys were carried out to prepare high density and high calorific value active alloys. Porous W skeleton was prepared by isostatic pressing with W powder as raw material. Then the skeleton was sintered to improve the skeleton strength. Finally, W-Ce alloy material with high density W as skeleton and active Ce as filling phase was prepared by liquid phase infiltration of Ce. The microstructure, properties and reactivity of W-Ce alloys prepared by different W skeleton preparation processes were studied. The results show that the density of W-Ce alloys is above 95 %. The phase composition of the alloy is W and Ce, and no intermetallic compound is formed. The dynamic compressive strength ranges from 621 MPa to 905 MPa, and the dynamic compressive plasticity ranges from 20 % to 30 %. The W-Ce alloy has a lower reaction threshold.

    • Cao Guoxin, Dong Jianxin, Zhang Sheng, Jiang He, Xie Guoliang, Nie Zhihua, Ma Tengfei, Fu Baoquan

      2024,53(5):1371-1377 DOI: 10.12442/j.issn.1002-185X.20230797

      Abstract:The flow behavior and microstructural evolution of a high-density Ni-42W-10Co-1Mo (wt.%) alloy were investigated at 1150-1300°C under strain rates of 0.001-1s-1 using a Gleeble-1500D. The results show that the initial microstructure was compsed of face-centered cubic matrix and σ phase. The flow stress was sensitive to the deformation temperature and strain rate, and the stress-strain curve showed a typical dynamic revertive softening characteristics deformated 1150°C, while typical dynamic recrystallization softening characteristics were observed deformed at 1200-1350°C. The Arrhenius equation was established based on the stress-strain curves, and the hot deformation activation energy of the Ni-42W-10Co-1Mo alloy was calculated to be 446.2 kJ/mol. The thermal processing map was constructed based on the dynamic material model to evaluate the thermal processing performance, and the instable zone was located at 1300°C under high strain rate. The deformation microstructureal evolution revealed that the dynamic recrystallization mechanism was discontinuous dynamic recrystallization, which preferentially nucleated around the σ phase. Finally, the optimized hot working window for Ni-42W-10Co-1Mo alloy was deformed at 1250-1300°C under strain rate of 0.1-0.01s-1.

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

      2024,53(5):1378-1384 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.

    • Zhang Danhua, Dong Di, Xiong Ning, Dong Zhi, Ma Zongqing

      2024,53(5):1458-1470 DOI: 10.12442/j.issn.1002-185X.20230688

      Abstract:Due to excellent properties such as high melting point, high strength, high hardness and high thermal conductivity, the molybdenum (Mo) and its alloys are widely used in aerospace, nuclear energy, electronics and chemical engineering. However, the material also has some inherent defects, such as insufficient high-temperature strength, low room temperature ductility, low recrystallization temperature and poor radiation resistance, etc. Various methods were researched to improve the material performances, and dispersed second phase particles is a simple and efficiency one. This article reviews the researches on the effects of different metal carbides and oxide strengthening phases on the microstructure and mechanical properties of Mo alloys. The influences of particle morphology, size distribution, volume fraction of oxides and carbides and interface structure with molybdenum matrix on the mechanical properties of molybdenum alloys were analyzed. The characteristics of different doping techniques to obtain high-performance molybdenum alloys were discussed, and the challenges and opportunities of dispersion strengthened molybdenum alloys in industrial applications and production were elaborated. This article aim to provide scientific basis for the design of dispersion strengthened molybdenum alloys, and expand the application of Mo alloys in various fields.

    • >Materials Science
    • Kang Minglong, Deng Yunlai, Lei Jinqin

      2024,53(5):1252-1261 DOI: 10.12442/j.issn.1002-185X.E20230036

      Abstract:Four-layer aluminum brazing sheets (4343/3003/6111/3003) with honeycomb sandwich structure are used as candidates for floor of high-speed train and ship deck, which are often exposed to corrosive environments. Microstructure and surface conditions of optimized 6111 aluminum alloy, which serves as the main support layer of this four-layer brazing sheet, have a great effect on the corrosion properties, which were investigated by a set of 6111 aluminum alloy ground with sandpaper of different grits. The results show that the AlFeSi(Mn, Cu) phase acts as cathode, due to its higher potential than that of the matrix, and forms a multi-stage system with adjacent matrix, which aggravates the surface corrosion. A smoother surface exhibits better corrosion resistance. Specifically, when lowering surface roughness from 18.03 μm to 0.92 μm, the surface volume decreases from 0.629 mm3 to 0.029 mm3, and the average number of intermetallic particles AlFeSi (Mn, Cu) is reduced from 1631 mm-2 to 917 mm-2, with area fraction decreasing from 3.93% to 0.92%. As a consequence, the average corrosion depth decreases from 237 μm to 95 μm.

    • Ma Li, Wei Zhenwei, Zhou Jie, Li Leyu, Deng Zhiwei, Fan Hao, Peng Wenyi, Liu Changkui

      2024,53(5):1262-1267 DOI: 10.12442/j.issn.1002-185X.20230510

      Abstract:Solution treatment is a common heat treatment to improve the comprehensive properties of 7050 aluminum alloys. Due to the quenching sensitivity of 7050 alloy, the water quenching temperature is an important factor affecting its performance. Different water quenching temperatures affect the saturation of solid solution obtained consequently and the size of precipitated phases, which in turn affects the properties of the alloy. The effect of water quenching temperature on the microstructure and properties of 7050 aluminum alloy during solution treatment was investigated. Results show that with increasing the water quenching temperature, the fraction of high angle grain boundaries (HAGBs) in the alloy increases according to the EBSD analysis; dislocations are mainly concentrated in HAGBs and areas with dense grain boundaries (GBs); the precipitated phase of the alloy continuously forms and grows at the GBs; the hardness of the alloy shows a trend of increasing first and then decreasing; the corrosion resistance deteriorates as the water quenching temperature increases. The alloy shows excellent comprehensive properties when quenched in water at 50 °C, with a microhardness of 1707.16 MPa and a corrosion potential of ?0.927 V.

    • Yang Taisen, Zhang Guiqing, Dai Zhiyong, Liang Xuewei, Wang Yingdi, Su Yunhai

      2024,53(5):1268-1276 DOI: 10.12442/j.issn.1002-185X.20230516

      Abstract:Molten chloride salt is excellent candidature for third-generation solar energy storage media due to its good energy storage advantages and low price. However, in the actual working environment, molten chloride salt has strong corrosion to metal pipes (Inconel 625 alloy). Inconel 625 welding wire is usually used as a repair material for solar pipeline. In order to solve the problem of strong corrosion of molten chloride salt to Inconel 625 cladding metal, Inconel 625 cladding metal was welded by MAG welding, and the effect of nano-MgO particles and MgCl2·6H2O in-situ self-generated MgO on the corrosion of KCl-MgCl2 molten salt was investigated. The results show that after 72 h of corrosion in KCl-MgCl2, KCl-MgCl2+5wt% MgO and KCl-MgCl2+5wt% MgCl2·6H2O, the mass loss of Inconel 625 cladding metal is 0.00714, 0.00512, and 0.00308 g·cm-2, respectively. The corrosion rate of Inconel 625 cladding metal in molten salt with in-situ self-generated MgO is decreased by 56.86% and 39.85%. Although the addition of nano-MgO particles in the molten salt can alleviate the corrosion of the chloride molten salt, the molten salt is agglomerated or settled, leading to a non-uniform distribution of MgO and MgCr2O4 protective shell layers. Adding MgCl2·6H2O to the molten salt can generate in-situ MgO, and the generated MgO and MgCr2O4 protective shells are more uniform, which hinder the erosion of corrosive media, so it is an effective method to reduce the corrosion of chloride molten salt.

    • Cao Miao, Deng Kunkun, Chen Huiqin, Duan Xingwang, Xu Yue, Li Fei, Che Xin, Wang Zhenbo, Yang Jingran, Zhang Zhihao, Li Ye

      2024,53(5):1277-1286 DOI: 10.12442/j.issn.1002-185X.20230545

      Abstract:Ti/Al layered metal composites (LMCs) with 3, 5 and 7 layers were prepared via hot-pressing followed by hot-rolling at 500 °C. The crack initiation and growth behavior in LMCs during tensile and Erichsen cupping tests were explored. The influence mechanism of interface constraint on the mechanical performance and stamping formability of LMCs was analyzed. Results show that LMCs exhibit strong interfacial bonding due to intermetallic phase with micron-scale thickness. As the layers of LMCs increase, their yield strength (YS) and ultimate tensile strength (UTS) increase accompanied with the reduction in the elongation (EL) and toughness, and their anisotropy of mechanical performance increases obviously due to the strong basal texture formed by hot-rolling. Meanwhile, both the work-hardening exponent (n) and plastic strain ratio (r) decrease, but the yield strength ratio (σs/σb) increases, which deteriorates the stamping formability of LMCs. Interfacial delamination plays a crucial role in the fracture for LMCs with fewer layers. The interface is prone to delamination because of poor interfacial bonding, which delays the fracture failure of LMCs by inhibiting crack initiation, promoting crack deflection and passivation, and reducing the driving force of crack propagation.

    • Li Huizhao, Liang Kaiming, Pan Rui, Zhu Xiaoteng, Jiang Bingxin, Tao Huwei, Li Zhihang, Hu Zhenggen, Zhang Hua

      2024,53(5):1287-1295 DOI: 10.12442/j.issn.1002-185X.E20230026

      Abstract:Self-designed induction coils, rigid restraint kits, and the existing laboratory induction heating apparatus were combined to conduct a local induction heating-based rigid restraint thermal self-compressing bonding (TSCB) treatment on a 5 mm-thick TC4 titanium alloy plate (the base metal), and the influence of holding temperature and heat treatment on the microstructure and mechanical properties of the joint was investigated. The results demonstrate that excessively low holding temperature (900 °C) results in insufficient atomic diffusion, while excessively high holding temperature (990 °C), exceeding the βα phase-transition temperature, leads to the formation of coarse Widmanstatten microstructures, both of which contribute to the decrease in the mechanical properties of the joint. As the temperature increases, the pressure applied to the joint by the thermal constraint stress field initially rises and subsequently declines, so does the quality of the joint connection. Optimal mechanical properties are achieved only when the holding temperature is slightly below the βα phase-transition temperature, specifically 950 °C, at which the microstructure distribution exhibits the highest level of uniformity, characterized by a significant presence of equiaxed α-phase grains. Additionally, the atomic diffusion is sufficiently enhanced, coupled with the highest pressure of the joint exerted by the stress field, resulting in the attainment of optimal mechanical performance. Upon annealing heat treatment at 650 °C for 3 h, the αβ phase-transition is observed, accompanied by a reduction in the degree of lattice distortion and grain refinement. The residual stress state of the TSCB joint transitions from tensile stress to compressive stress. The residual stress is significantly reduced, leading to stress relief. Consequently, the mechanical properties of the TSCB joint are improved, addressing the problem of low plasticity of the TSCB joint.

    • Li Chengbo, Hou Huibing, Liu Leilei, Huang Chengyi, Ren Yuelu, Du Jun

      2024,53(5):1385-1390 DOI: 10.12442/j.issn.1002-185X.20230521

      Abstract:This study focuses on the eutectic Al-14Cu-7Ce alloy to investigate the evolution of its microstructure and the changes in thermal conductivity and mechanical properties by adjusting the amount of Mg element added. The results show that the as-cast Al-14Cu-7Ce alloy is mainly composed of α-Al and Al8CeCu4 phases, with a microstructure consisting of coarse eutectic structure (α-Al + Al8CeCu4). The addition of a small amount of Mg element can refine the eutectic structure and improve its mechanical properties. With an addition of 1.0% Mg, the alloy"s yield strength and tensile strength increase to 164 MPa and 263 MPa, respectively, with an improvement of 29% and 19%. The elongation at break is enhanced to 4.5%, with an improvement of approximately 41%. The thermal conductivity is 130.2 W/(m·K), with a decrease of about 12%. As the Mg element is further increased to 2.0%, the mechanical properties of the alloy decrease, with the yield strength and tensile strength decreasing to 151 MPa and 249 MPa, respectively. The elongation at break decreases to 3.9%, and the thermal conductivity decreases to 108.3 W/(m·K). The decrease in thermal conductivity is mainly due to the solid solution of Mg atoms acting as scattering centers, hindering the movement of electrons within the lattice, and reducing the average free path of electrons and phonons. When the Mg content reaches 2.0%, the Mg reacts with Al and Cu elements to form the Al2MgCu phase, which is distributed in a fishbone-shaped eutectic structure (α-Al + Al2MgCu) at grain boundaries. This increases the volume fraction of the second phase in the alloy and further deteriorates its electrical and thermal conductivity. The decrease in mechanical properties of the alloy is mainly attributed to the presence of two eutectic structures, (α-Al + Al8CeCu4) and (α-Al + Al2MgCu), which increase the occurrence of microcracks at the phase interfaces. In summary, the addition of 1.0% Mg can obtain an Al-Cu-Ce eutectic alloy with high strength and high thermal conductivity.

    • Zhang Yunhua, Zheng Sen, Lou Diming, Fang Liang, Feng Qian

      2024,53(5):1391-1400 DOI: 10.12442/j.issn.1002-185X.20230334

      Abstract:Based on XRD, XPS, H2-TPR and other characterization methods for physical and chemical properties and catalyst activity evaluation methods, the physical and chemical properties and catalytic activity of CDPF samples doped with different bimetal oxide under hydrothermal aging condition were studied. The results show that Ce-Zr bimetal oxide doped sample has good stability in phase structure and cell parameters, Zr-Fe bimetal oxide doped sample can better inhibit the dispersity of noble metal on carrier’s surface. For Fe-Ce and Zr-Fe bimetal oxide doped CDPF samples, during high-temperature aging process, the dispersed metal oxides undergo solid solution again, which will cause a formation of solid solution and more oxygen vacancies. After experiencing high-temperature hydrothermal aging process, the diffraction characteristic peaks of samples all migrate various degrees towards the high-temperature direction. Fe-Ce bimetal oxide doped sample shows a low degree of migration while Ce-Zr bimetal oxide doped sample is higher. Fe-Ce and Zr-Fe bimetal oxide doped aged samples showed higher oxidation activity of CO and show a low-level degradation. Ce-Zr bimetal oxide doped aged sample showed a slight decrease in the oxidation activity of C3H8. The catalytic activity for NO of Ce-Zr bimetal oxide doped sample decreases slightly after high-temperature hydrothermal aging process.

    • Jiang Yi, Dai Yile, Wang Qing, Xie Xianfei, Dai Jianfeng

      2024,53(5):1401-1408 DOI: 10.12442/j.issn.1002-185X.20230153

      Abstract:The photoanode of QDSSCs was fabricated using industrially produced black titanium dioxide with stable yield and performance. Through comprehensive performance characterization and theoretical calculation studies, the photoanode was compared to common Anatase TiO2 and Rutile TiO2. Results indicate that the introduction of oxygen vacancies in Magonelli Ti8O15 leads to a decrease in conduction band bottom, shrinkage of band gap, and extension of absorption spectrum from ultraviolet to visible range.Key words: Titanium dioxide, Quantum dots, Solar cells, Magonelli Ti8O15

    • Wu Xuanxuan, Dong Xianjuan, Xu Yong, Lu Shiqiang, Tu Zeli, Wang Yuhang

      2024,53(5):1409-1416 DOI: 10.12442/j.issn.1002-185X.20230163

      Abstract:The Gleeble-3800 thermal simulator was used to conduct isothermal constant strain rate thermal compression tests on TB15 titanium alloy to study its thermal deformation behavior at deformation temperatures of 810-930°C, strain rates of 0.001-10s-1 and height depression of 60%; three constitutive relationship models, physical, support vector regression (SVR) and response surface, were developed to predict the flow stresses of TB15 titanium alloy were predicted by three physical, support vector regression (SVR) and response surface constitutive models, and the prediction accuracy of the three constitutive models was compared. The results show that the flow stress of TB15 titanium alloy decreases with decreasing strain rate and increasing deformation temperature, and the change of peak stress is more sensitive to the strain rate; the correlation coefficient R of physical, SVR and response surface constitutive models are all greater than 0.98, but the R value of response surface constitutive model reaches 0.993, and the frequency of the relative error of the response surface constitutive models ±5% of the predicted value reached 67.9%, which was greater than that of the physical constitutive models at58.6%. The significance test value P<0.0001 of the constructed response surface constitutive model was also obtained by ANOVA, indicating that the regression relationship between the flow stress predicted by the response surface constitutive model and the deformation temperature, strain rate and strain was significant and had higher accuracy than the physical constitutive model and SVR constitutive model, which could better predict the flow stress of TB15 titanium alloy.

    • Huang Yimeng, Ma Xiaochun, Zhang Haizhou, Zhang Haitao, Ren Xinyuan, Wang Huining, Huang Taizhong

      2024,53(5):1417-1428 DOI: 10.12442/j.issn.1002-185X.20230167

      Abstract:With the increasing pollution of nitrogen oxides, the development of denitration catalysts have become one key factor for the treatment. In this paper, Ni0.09Ti0.91O2 nanotube supported copper denitration catalysts were prepared by hydrothermal and calcination two-step methods. The structure and catalytic denitration performance were studied. Results showed that the nanotube structure of the catalysts were determined by N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and other methodologies. Ni0.09Ti0.91O2 nanotubes are anatase structures, copper atomic clusters are distributed on the surface of the nanotubes, and nitrogen adsorption and desorption tests determined that the specific surface area of Ni0.09Ti0.91O2 before and after loading copper was 263.51 and 216.5422 m2 g-1,respectively. The copper on the surface of the nanotubes was uniformly dispersed. The denitration efficiency of Ni0.09Ti0.91O2 nanotube with 7wt% copper was quite approach to 100%, which was higher than that of the nanotube catalyst without copper, and it had good anti-poisoning performance. The results of in-situ infrared spectroscopy diffuse reflection tests showed that the NH3-SCR process of Ni0.09Ti0.91O2-loaded copper followed the L-H mechanism. In this paper, the denitration performance of Ni0.09Ti0.91O2 nanoparticle-supported copper was also studied as a comparison. The catalyst of Ni0.09Ti0.91O2 nanotube loaded with 7wt% copper showed the best denitrification and anti-poisoning properties, which had good application prospects.

    • Cheng Junjun

      2024,53(5):1429-1436 DOI: 10.12442/j.issn.1002-185X.20230169

      Abstract:TiO2 anode has received wide attention because of its good structural stability and safety during the charging and discharging of lithium-ion battery. However, the inherent poor conductivity of TiO2 limits its capacity and cycling stability at high current densities. In this paper, coaxial indium tin oxide-TiO2 nanotube complexes (ITO-TiO2NTs) were successfully prepared by vacuum mechanical press injection method and subsequent annealing treatment. As an anode material for Li-ion batteries, ITO-TiO2NTs exhibited a high capacity of 295.9 mAh g-1 after 350 cycles with a current density of 0.2 A g-1. The ITO acts as a conductive core in the three-dimensional structure, which improves the overall conductivity and facilitates the fast electron and Li-ion transfer, thus improving the cycling stability and multiplicity performance of the composite. The vacuum mechanical press injection method proposed in this paper provides a simple and efficient method for composite modification of TiO2 nanotube array thin film materials, which is of great significance.

    • liranran, yangjiacai, linjianguo, zhangdechuang

      2024,53(5):1437-1443 DOI: 10.12442/j.issn.1002-185X.20230162

      Abstract:In this paper, Zn-3Cu alloy is taken as the research object. The effects of rolling deformation on the microstructure, mechanical properties and corrosion resistance of Zn-3Cu alloy were studied. It is found that with the increase of rolling deformation, the grain refinement of Zn-3Cu alloy matrix is deepened, and the CuZn5 phase in the alloy is elongated and partially broken along the rolling direction. The strength of Zn-3Cu alloy increases first and then decreases, and the plasticity increases continuously. The Zn-3Cu alloy with 60 % deformation has the highest yield strength, reaching 263.1 ± 4.9 MPa. With the increase of deformation, the corrosion resistance of the as-rolled Zn-3Cu alloy gradually decreases, and the as-cast Zn-3Cu alloy exhibits excellent corrosion resistance.

    • Ao Qingbo, Wang Jianzhong, Ma Jun, Wu Chen

      2024,53(5):1444-1448 DOI: 10.12442/j.issn.1002-185X.20230273

      Abstract:In this paper, 8μm stainless steel fiber felt was used as raw material, and the stainless steel fiber porous material were prepared by volume-weighing method and high temperature sintering with different porosity, average pore size and thickness. Positive gradient structure, inverse gradient structure and film composite structure were designed by structural optimization. The sound insulation performance of the three kinds of the structures was tested, and the sound insulation characteristics of the structures were studied respectively. The sound insulation results indicate that the stainless steel fiber porous material has a certain sound insulation performance. The thickness is 20 mm, the porosity is 85 %, and the average sound insulation of the stainless steel fiber porous material is 18.92 dB in the frequency range of 50 ~ 6400 Hz. The lower the porosity, the smaller average pore size, the thicker the thickness, the better the sound insulation performance of the material; The sound insulation performance of the designed positive gradient and the inverse gradient structures is worse than the single layer stainless steel fiber porous material. The sound insulation performance of the stainless steel fiber porous composite material with film material is greatly improved at medium and high frequencies. The thickness is 20 mm, the average sound insulation is 27.86 dB, and the highest is increased by 16.96 dB.

    • Lei Lei, Zhu Qiwei, Zhao Qinyang, Zhao Yongqing

      2024,53(5):1449-1457 DOI: 10.12442/j.issn.1002-185X.20230266

      Abstract:TC21 alloy has high strength and fracture toughness, however, the mechanism of crack initiation and propagation during impact is not clear, and the relationship between impact toughness and tensile properties is yet to be studied. In this work, different microstructures are prepared by regulating the solid solution temperature and cooling rate to study the tensile and impact properties. The results show that tensile performance and impact toughness exhibit different variation laws. The impact toughness of the bimodal structure with better plasticity is lower than that of the full lamellar structure with the worst plasticity, indicating that the intrinsic control mechanisms of tensile properties and impact toughness are different, which is further confirmed by the post-aging properties (no significant change in plasticity but significant decrease in impact toughness after aging). During tensile deformation, plastic deformation occurs in the whole region of the specimen before necking occurs, and the coordination deformation between αp and βt in the bimodal structure is fully developed, while the full lamellar structure has a larger colony size and its internal lamellar α orientation is uniform, and the dislocation slip length is larger, making it susceptible to plastic strain localization, resulting in a poorer strength plasticity matching than that of the bimodal structure. Under the influence of high strain rate, the crack initiation and propagation at the notch root are rapid, and the plastic deformation is concentrated in a small range near the crack tip, resulting in the coordination deformation between αp and βt cannot be fully played. In this case, the colony interface of the full lamellar structure has little influence on the plastic deformation, and the lamellar α and β become the control units of plastic deformation. The coarse lamellar α/β has better plastic deformation ability, resulting in higher crack initiation energy, contrary to the poor plasticity exhibited by stretching. In addition, the large angle interface of α colony causes the deflection of cracks and forms a tortuous path, resulting in higher impact toughness than the bimodal structure.

    • >Reviews
    • Xu Jianbo, Zhang Bowen, Qu Wentao, Sun Linlin

      2024,53(5):1296-1309 DOI: 10.12442/j.issn.1002-185X.20230543

      Abstract:Titanium and its alloys, characterized by light weight, excellent corrosion resistance, high strength, low elastic modulus, superior biocompatibility, and outstanding osseointegration, have become one of the mostly widely used metallic materials in aerospace and biomedical fields. However, their relatively low plasticity, hardness, and wear resistance constrain further development and applications. Laser surface treatment (LST) technology, which enhances surface properties without altering the bulk material, has emerged as a beneficial approach to modify the surface of titanium alloys. The research advancements and current applications of LST in surface modification of titanium and its alloys were reviewed. The mechanisms, process parameters, surface characteristics, and microstructures of various LST methods were analyzed, including laser transformation hardening (LTH), laser surface remelting (LSR), laser shock peening (LSP), laser surface alloying (LSA), laser cladding (LC), and composite LST techniques. The applications of LST in aerospace and medical domains were also clarified, as well as existing limitations, future research directions, and insights into the developmental trends of LST for titanium and its alloy materials. The objective is to advance LST innovation and to pave new avenues for the application of titanium alloys in various sectors.

    • Zhang Yuan, Yang Yuzhuo, Liu Yun, Liu Wei, Tian Yaqiang, Chen Liansheng

      2024,53(5):1310-1320 DOI: 10.12442/j.issn.1002-185X.E20230027

      Abstract:Magnesium alloys offer a lot of potential in the biomedical fields, due to their suitable elastic modulus for human bone, spontaneous degradability, and excellent biocompatibility, while low absolute tensile or yield strength and barren plastic abilities at room temperature significantly restrict their applications. As a successful method of enhancing mechanical properties, the hot deformation process can not only refine the grain sizes and broken sediments, but also introduce the high-density dislocations and change the texture orientation to improve the strength and plasticity. Based on the microstructure evolution laws, the latest research progress of Mg-based alloys under various hot deformation processes was reviewed. The differences in the deformation methods of rolling, forging, extrusion, and high-pressure torsion were compared. Under various hot deformation methods, the mechanism of grain refinement and the impact of dynamic recrystallization and dislocation propagation on the mechanical properties of Mg alloys were discussed. In addition, the relationships between microstructure and mechanical properties of hot-deformed Mg alloys were summarized.

    • XU Mingyang, LI Minghua, ZHANG Yao, LIU Peiqiao, LI Kuo, WANG Dongwei, YU Guanghua

      2024,53(5):1471-1485 DOI: 10.12442/j.issn.1002-185X.20220037

      Abstract:Co-based Heusler alloy is a kind of intermetallic compound with highly ordered crystal structure. Its chemical composition is usually expressed by Co2XY, where X is a transition metal element and Y is a main group element. Compared with other materials, it has higher spin polarizability, higher Curie temperature and lower damping factor. Based on these excellent characteristics, Co-based Heusler alloy has great application prospects in spin valves, tunnel junctions and semiconductor spin field effect transistors. This article reviews recent international studies on Co-based Heusler alloys on perpendicular magnetic anisotropy and spin-orbit torque. We summarized the influencing factors of perpendicular magnetic anisotropy and spin-orbit torque from the aspects of alloy composition, microstructure, magnetic layer thickness, buffer layer material, oxide layer material, element diffusion, etc. Which will help us better understand its deep-seated physical mechanism, as well as the challenges and prospects in future research.

    • XU Hanyuan, HUANG Taiwen, AI Cheng, MIAO Linkun, ZHANG Jun, LIU Lin

      2024,53(5):1486-1492 DOI: 10.12442/j.issn.1002-185X.20230568

      Abstract:With outstanding comprehensive performance at high temperature, Nickel-based single crystal superalloy is the preferred material for aero-engine turbine blades, vanes and other components to withstand challenging service environment subjected to high temperature and intense stress. At present, various complex cooling structures are often used in the design of high-efficiency cooling blades to enhance blade temperature tolerance, among which the micro-cooling structure represented by lamilloy and double wall cooling are the main trend. However, the existence of ultra-thin wall structures in these complex turbine blades has become critical aspect and challenge in blade manufacturing. This paper provided an overview of the development trends in thin-walled structure of Ni-based single-crystal superalloys, analyzed the defects arising from thin-walled constrained space and the law of dendrite growth, elaborated the influence of thin-walled structure on mechanical properties and provided a prospect on advanced turbine blades preparation and development trend of its microstructure regulation.

    • Ren Li, Wang Xin, Wang Shuo, Wu Wenbin, Zuo Meihua, Xing Wangyan, Fan Weifeng, Zhang Bin, Zhang Jun, Xiang Wei

      2024,53(5):1493-1502 DOI: 10.12442/j.issn.1002-185X.20230137

      Abstract:In order to synthesize high performance nickel-rich cathode, it is necessary to adopt favorable calcination temperature, calcination time and cooling procedure to lithiate hydroxide precursor, so as to form cathode material with better crystal structure and grain morphology in a controlled way. However, due to the large number of parameters involved in the calcination process, it is still challenging to reasonably design the calcination process which is required for preparing nickel-rich positive electrode with ideal structure and morphology. Therefore, it is necessary to deeply understand the evolution and formation rule of the phase, structure and morphology of intermediate during high temperature calcination, so as to provide reference for the design of nickel-rich cathode calcination process and directional control of structure. In this paper, the phase composition changes of precursor during the lithiation are briefly introduced from the point view of thermodynamic phase equilibrium. Secondly, the reaction mechanism and phase evolution of the intermediate are introduced based on in situ testing and theoretical calculation analysis. Then, the surface reconstruction phenomenon which is occurred in cooling process and significantly affects the properties of nickel-rich cathode materials is introduced, and the reasons for surface reconstruction are summarized. Finally, the morphology evolution and factors that affect the morphology during lithiation are introduced. Finally, the problems in the calcination process of nickel-rich cathode are discussed. The structural evolution and regulation of intermediate during high temperature lithiation process introduced in the paper could provide reference for relevant professionals to develop nickel-rich cathodes.

    • Hu Lingjie, Wang Liuying, Liu Gu, Ge Chaoqun, Xu Kejun, Wang Weichao, Wang Wenhao

      2024,53(5):1503-1516 DOI: 10.12442/j.issn.1002-185X.20230152

      Abstract:Electrochromic materials have important application prospects in energy-saving windows, smart displays, and military camouflage protection, as they can stably and reversibly change their optical properties under an external electric field. By using multi-component synergistic methods, electrochromic devices can integrate more functions or new features, making them develop towards the direction of multifunctional integration and further expanding their application fields. In this article, we comprehensively review the latest research results on the functional design of electrochromic devices in the past decade, discussing their integration mode, working mechanism, and design strategies. We elucidate their application prospects in smart windows, energy storage devices, sensors, and military camouflage, and analyze in detail the key problems and major challenges that functional electrochromic devices face. We also propose new solutions and development directions, which are of great significance for guiding the research on the functionalization of electrochromic devices.

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    • Ge Shujin, Chen Shuaifeng, Deng Siying, Zheng Li, Song Hongwu, Zhang Shihong

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240220

      Abstract:The equal channel angular bending of AZ31 magnesium alloy rolled sheet (2mm) in different paths was tested at 150 ℃. The internal microstructure and mechanical properties of the sheet were studied after 5 ECAB passes on the same path, ND rotation path and RD rotation path respectively. The results show that after 5 ECAB passes , a large amount of ETW and a certain amount of CTW are introduced into the sheet. It can effectively improve the texture of the base plane. The area of ETW is about 28.7%. After annealing treatment, the elongation of the sheets through equal channel angular bending is obviously improved. In particular, the elongation of the deformed sheet rotated 5 times around the rolling direction (RD) can reach 28.8% and the tensile strength is 235.7 MPa. Compared with the original sheet, the relative increase rate of the elongation is 57.4%, while the tensile strength is only 3.8% lower.

    • chen shijie, zhang shirong, xue lihong, yan youwei

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240224

      Abstract:Mechanical alloying combined with spark plasma sintering was adopted to prepare W23.5Ta23.5Cr23.5V23.5Ti6 high entropy alloys. The effects of ball milling times on the elemental distribution and micrsstructure of the alloys were explored. It is found that the powder after 40 h of ball milling has a homogeneous particle size with about 3.65 ± 1.91 μm, and presents an equiaxed particle morphology. A dense uniform alloy can be obtained after the powder sintered by SPS at 1500 ℃. The relative density is above 99.0%. The WTaCrVTix solid solution with BCC structure is continuously distributed, in which the atomic ratios of W, Ta, Cr and V are close to the equiatomic ratios. A small amount of laves phase is distributed in the matrix. The TiO particles with FCC structure have an average size of 1.08±0.38 μm and are uniformly distributed in the matrix. Its room-temperature compressive yield strength, high-temperature compressive yield strength and microhardness are 2870 MPa、1954 MPa and 873.4 ± 7.6 HV, respectively.

    • Guo Yuhui, Cao Taifeng, Wang Shaohua, Qiao Junwei

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240235

      Abstract::The residual stress inside the lead frame C19400 alloy leads to warping behavior of the alloy strip, greatly affecting the performance of the alloy. Therefore, it is meaningful to conduct in-depth research on the correlation between residual stress, mechanical properties, and microstructure inside C19400 alloy, which is beneficial for improving the theoretical basis for eliminating residual stress in lead frame C19400 alloy. The mechanical properties, microstructure, and residual stress of the cold-rolled and aged samples of C19400 alloy were systematically studied. The results show that the maximum tensile strength of the rolled alloy can reach 546 MPa. In addition, the results of macroscopic residual stress and microscopic residual stress both indicate that the residual stress of the rolled alloy is higher, indicating that residual stress is mainly generated during the uneven cold rolling plastic deformation process, which is verified in the kernal angle misorientation (KAM) distribution map, because the KAM value of the rolled alloy is higher than that of the annealed alloy. At the same time, the evolution of macroscopic and microscopic textures in C19400 alloy was revealed in detail. The results showed that the texture types in both rolled and annealed alloys were Brass (011)<211>, Copper (112)<111>, and S (123)<634>deformation textures and recrystallized Cube (001)<100>textures, and the strength and volume fraction changes of Copper (112)<111>textures were consistent with residual stress, This indicates that the presence of Copper (112)<111>texture is more conducive to the generation of residual stress.

    • Shu Guogang, Xuan Weidong, Yu Xu, Duan Fangmiao, Bai Xiaolong, Ge Bingming, Wang Baojun, Zhang Zhenqiang, Zhang Chengjiang, Ren Zhongming

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240238

      Abstract:The formation mechanism of freckles in large-sized UGTC47 directionally solidified turbine blades for heavy-duty gas turbines and their effects on the stress rupture property performance were investigated using optical microscopy (OM), scanning electron microscopy (SEM), and endurance performance testing. The results indicate that freckle defects form in both the middle and root regions of the blade tenon, with the formation mechanism being the density inversion caused by liquid phase segregation, resulting in fluid convection under the action of gravity, leading to the fracture of dendrite arms and thus the formation of freckles. At 900 ℃/380 MPa, the percentage of freckle area has a significant impact on the endurance performance of the UGTC47 alloy. With the increase in freckle content, the endurance life of the alloy decreases from 131.83 h without freckles to 33.66 h.

    • Cheng Zhou, Lei Jin, Gaoyang Jing, Boyan Yu, Jun Zhao

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240244

      Abstract:In the present study, the coarsening behavior of γ? phase at different temperatures and the compression property of a novel Co–Ni–Al–W superalloy was investigated. The evolution of the mean radius and volume fraction of the γ? phase indicates that the coarsening behavior follows the classical Lifshitz-Slyozov-Wagner (LSW) model. The coarsening rate of the γ" phase exhibits a significant dependence on the aging temperature, increasing from 1.30×10-27 m3/s at 800 ℃ to 9.56×10-27 m3/s at 900 ℃. The activation energy of γ? phase, influenced mainly by W diffusion in the γ matrix, is found to be 210 kJ/mol. In particular, the studied Co-Ni-Al-W alloy possesses a good combination of a high γ? solvus temperature of 1221 ℃ and a low density of 8.7 g/cm3. Besides, compression yield strength of the developed Co-Ni-Al-W alloy at ambient and high temperatures are higher than those of other recently γ?-strengthened Co-based superalloys.

    • Chao Shuang, Cao Jingjing, Li Hezong, Fan Lei, Yang Junheng, Christopher Martin Harvey

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240245

      Abstract:Ni-P-SiCP coatings were deposited on 42CrMo steel by electroless plating. The surface morphologies and phase structures of the Ni-P-SiCP coatings were analyzed at different SiCP concentrations and heat treatment temperatures by SEM and XRD. The microhardness, corrosion re-sistance and wear resistance of the Ni-P-SiCP coatings were also studied. The Ni-P-SiCP coatings exhibited “cauliflower”-like morphology. Increasing the SiCP concentration reduced the size of cellular structure. The microhardness and corrosion resistance initially increased and then decreased with increasing SiCP concentration, peaking at 5 g/L SiCP, 753 HV and -0.363 V, respectively. The Ni-P-SiCP coatings exhibited an amorphous structure, and the width of the diffuse diffraction peak became narrower with increasing SiCP concentration. It is suggested that SiCP inhibit the deposition of P and promote microcrystalline transformation. After heat-treatment at 350℃, the Ni-P-SiCP coatings crystallized, precipitating a Ni3P phase. Heat treatment at 400℃ for 1 h maximized the structure. The synergistic effect of the Ni3P precipitation phase and the SiCP dispersion phase promoted the densification of the cellular structure, which had the best microhardness (1411 HV), optimal corrosion resistance (-0.277 V) and excellent wear resistance. Its wear mechanism is dominated by micro-cutting abrasive wear with slight adhesive and oxidative wear.

    • Liu Peng, GuoXuan, GaoDongfang, ZhaoYangyang, Qiaoyang

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240249

      Abstract:In recent years, magnesium alloy materials have attracted much attention due to their biodegradability and similar mechanical properties to cortical bone. In this paper, the surface of homemade magnesium alloy was laser processed, and the laser-etched morphology was determined as grooves by observing the surface morphology of sheep rib bone, and the hydrophilicity of different morphologies was investigated by contact angle test. Through the cell climbing test, the effects of different morphologies on cell climbing, growth and migration were investigated. The results show that the wetting angle of the field shape is smaller than that of the groove shape, and the field shape has better hydrophilicity; compared with the smooth surface, the field shape surface has better cell adhesion, and the depression and bumps are full of cells; therefore, it is suggested that the micropatterns obtained by the laser processing are conducive to the enhancement of biocompatibility, which will provide new theoretical basis for the implantation of magnesium alloys into the human body as bone grafting plates in the future.

    • lichunling, lishaobing, lixiaocheng, lichunyan, koushengzhong

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240262

      Abstract:This study conducted a suction casting experiment on Zr55Cu30Al10Ni5 amorphous alloy. Based on ProCAST software, numerical simulations were performed to analyze the filling and solidification processes of the alloy. 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 casting experiment was carried out. The results showed that increasing the suction casting temperature will enhance the fluidity of alloy melt, making the flow rate unstable in the filling process, which was not conducive 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 experiment. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) data confirmed that the prepared Zr-based micro-gear had an amorphous structure, clear tooth profile, and good surface quality.

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

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240270

      Abstract:This paper is to prepare Co-based alloy-coated metal Zr using laser melting and cladding technology, to study the difference between the high-temperature oxidation behavior of pure metal Co coatings and Co-T800 alloy coatings, as well as the wear resistance of the coatings, and also to investigate the effect of changing the laser melting process on the coatings. The oxidation weight gain of two coated Zr alloy samples at 800~1200 ℃ and the high-temperature oxidation behavior at high temperature for 1h were studied. The analysis of the results showed that the Co coating and the Co-T800 coating have better resistance to high-temperature oxidation. After oxidizing at 1000 ℃ for 1 h, the thickness of the oxide layer of the uncoated sample was 241 μm, while the thickness of the oxide layer of the Co-based coated sample was only 11.8~35.5 μm. The friction wear test showed that the depth of the abrasion mark of the coated specimen is only 1/2 of the substrate, and the hardness and wear resistance of the Zr substrate have been greatly improved. The disadvantage of Co-based coatings is the reduced performance of corrosion resistance in 3.5% NaCl solution.

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

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240272

      Abstract:In recent years, degradable metals, represented by magnesium and magnesium alloys, have gradually become the research focus of fracture internal fixation and bone defect repair materials due to their good biocompatibility, suitable elastic modulus and degradable properties. The Mg-3 wt%Zn-1 wt%Ca-0.5 wt%Sr alloy is considered a competitor in the biomaterial field thanks to its unique composition of essential nutrients and excellent mechanical properties. However, due to the existence of coarse second phase in the alloy, the degradation rate of the alloy is too fast, and there is a serious phenomenon of gas production during implantation, which limits the clinical promotion and application of the alloy. In order to further optimize the properties of the alloy, this study adopts extrusion composite high pressure torsion (HPT) for deformation processing. 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 of the alloy, and then improving the mechanical and corrosion resistance of the alloy. The high pressure torsion deformation process is applied to the processing of magnesium and magnesium alloys. It can improve its potential in biomedical applications. The results showed that after HPT processing, the grains at the periphery of the alloy were significantly refined to a nanometer level, reaching approximately 98 nm, the distribution of the secondary phase also improved significantly, transforming the original streamlined organization into a dispersed distribution. This change in microstructure led to a significant strengthening of the alloy, with a noticeable increase in hardness from 60.3HV in the as-extruded state to 98.5HV.

    • Yuan Haojie, Tian Xin, Liu Ying

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240187

      Abstract:In order to enhance the high-temperature antioxidant protection provided by glass coating on titanium alloy, this study introduces the Ti3AlC2 reinforcing phase into pure glass coating slurry by ball milling method, and scrapes the slurry onto the surface of TC4 alloy and conducts antioxidant test. The results show that when 5 wt.% Ti3AlC2 (TAC5 coating) was added, the α-contamination layer thickness of the TC4 alloy substrate is minimized, measuring approximately 65.78 μm. In comparison to the pure glass coating under similar test conditions, the α-contamination layer thickness of the TAC5 coating is reduced by about one quarter. This reduction occurs as the Ti3AlC2 reinforcing phase reacts with the infiltrated oxygen in the coating, thereby diminishing contact between the substrate and oxygen and improving the coating’s ability to safeguard the TC4 alloy against oxidation at elevated temperatures.

    • Niu Yong, Wang Bingtao, Wang Yaoqi, Zhu Yanchun

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240189

      Abstract:The isothermal transformation process of TC17 alloy was investigated using microstructure analysis and numerical simulation. The experimental results show that TC17 alloy first precipitates α-phase at or near grain boundaries, and with the increase of aging time, a large number of needle-like α-phase is precipitated inside the grains, and the precipitated α-phase gradually becomes fine as the aging temperature decreases; with the decrease of the aging temperature, the rate of precipitated α-phase shows a tendency of increasing and then decreasing, and the phase transition driving force and solute atom diffusion rate reach the maximum matching degree at aging temperatures of 650°C-600°C. The maximum rate of precipitated α-phase is reached currently. At the aging temperature of 650°C-600°C, the phase transition driving force and the diffusion speed of solute atoms reach the maximum matching degree, and the rate of precipitating α-phase reaches the maximum currently. Numerical simulation results show that the α-phase precipitation rate is the fastest at an isothermal temperature of 650°C, and the results are in good agreement with the experimental results.

    • Luo Hengjun, Deng Hao, Yuan Wuhua, Liu Wenhao, Chen Longqing

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240192

      Abstract:The microstructure and mechanical properties of Ti-5Al-5Mo-5V-1Cr-1Fe (Ti55511) alloy subjected to a double annealing process are significantly influenced by the holding time. This study explores the impact of holding time on the microstructure and tensile properties of Ti55511 titanium alloy during double annealing. The findings reveal that the shape and size of the primary α (αp) phase are predominantly influenced by the holding time at the first stage. As the holding time increases, the long strip of αp transforms into a short rod due to the terminal migration mechanism, and the growth of αp slows down after 2 hours. The volume fraction of αp is mainly affected by the holding time of the second stage, leading to an increment in the prolonged holding time, along with a synergistic effect on the precipitation of αs. The mechanical properties of TI55511 alloy are influenced by both αp and αs. Tensile results indicate that the optimal holding time range is 1-4 hours for the first stage and 0.5-2 hours for the second stage, respectively.

    • , huangbensheng, jiechuandi, chengen, dujiao, sunhaishen

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240198

      Abstract:Cermets, known for their excellent hardness, strength, and wear resistance, have extensive applications in many industries. Currently, a significant research challenge involves enhancing the mechanical properties and oxidation resistance of metal-ceramics while reducing production costs through improvements in the ceramic phases and variations in the types and compositions of metals. In this study, we employed powder metallurgy to fabricate TiC-NiCr cermets and examined their oxidation behaviour at 900°C. The results revealed a uniformly structured TiC-NiCr cermets with excellent mechanical properties, exhibiting a Rockwell hardness value of (HRC65) and a flexural strength of 1450 MPa. This study investigates the high-temperature oxidation mechanism of TiC-based cermets using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Incorporating Ni and Cr elements, along with their solid solutions, not only bonds the hard phase TiC to ensure the physical performance of the cermet but also impedes internal diffusion during oxidation by forming a dense composite oxide layer, thereby enhancing its oxidation resistance. The TiC-NiCr cermet exhibited a dense protective oxide film at 900°C and endured continuous oxidation for approximately 1000 h. This paper presents a methodology for fabricating of TiC-NiCr metal matrix composites and evaluates their oxidation resistance, providing a theoretical and practical basis for enhancing both mechanical properties and oxidation resistance while reducing production costs.

    • Hu Lijuan, Wang Zixuan, Qiang Yuanyuan, Lin Jiamao, Shi Jin, Yao Meiyi, Xie Yaoping

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240202

      Abstract:Dental implants influence the biological response of bone tissue during chewing, thus necessitating implant materials with long-term stability and favorable biomechanical properties. To assess the biomechanical performance and potential applications of a novel zirconium alloy, this study employed finite element method to investigate the effect of material elastic modulus on stress and strain distribution in implants and bone tissue. Utilizing dental manufacturer and clinical statistical data, implant and mandible bone models were established. Material parameters for prepared Zr30Ti and Zr22Nb alloys were obtained through tensile testing, with Ti6Al4V (elastic modulus: 110 GPa) and Zr24Nb (elastic modulus: 30 GPa) selected as contrasting materials. Bone tissue was modeled using orthotropic material properties closer to real characteristics. Vertical and inclined loads were applied according to ISO 14801 standards, with a tilt angle of 30°. All studies were referenced against Ti6Al4V, and the results showed that: The decrease in implant elastic modulus detrimentally affects its load-bearing capacity under inclined loads, with stress increments for Zr30Ti (76 GPa), Zr22Nb (59 GPa), and Zr24Nb (30 GPa) of 2.98%, 5.47%, and 14.55%, respectively. However, maximum stresses still remained below their respective strengths (952 MPa, 611 MPa, respectively). The stress transmission from implants was primarily borne by cortical bone, with maximum stress increments in cortical bone under inclined loads for Zr30Ti, Zr22Nb, and Zr24Nb of 17.59%, 31.92%, and 79.14%, respectively. The risk of cortical bone overload increases with decreasing implant elastic modulus, but the stresses generated by Zr30Ti and Zr22Nb within cortical bone remained below cortical bone strength, ensuring favorable application safety. The stress transmitted from implants to cortical bone increased and became more uniform with decreasing elastic modulus, with average Mises stress increments at the implant-bone interface for Zr30Ti, Zr22Nb, and Zr24Nb under inclined loads of 12.75%, 122.94%, and 155.11%, respectively. While The stress difference at the interface for implant-bone decreased by 16.82%, 29.45% and 65.41%, respectively. This is attributed to larger deformation zones within implants with lower elastic modulus, where under inclined loads, the internal maximum strains in the neck region of Zr30Ti, Zr22Nb, and Zr24Nb implants were 2 times, 2.61 times, and 4.87 times greater than Ti6Al4V, respectively, with minimal differences in modulus between implants and bone tissue promoting more coordinated deformation at the interface.Thereby it can promote stress transfer to cortical bone and reduce interfacial stress difference. With elastic modulus decreases, the stress at the bottom of cancellous bone implant sites gradually decreases, and the overall stress was concentrated in the upper part. The stress distribution of the cancellous bone in Zr30Ti and Zr22Nb zirconium alloy implants was more uniform.

    • Bi Guangli, Wei Zhichao, Jiang Jing, Zhang Niuming, Li Yuandong, Chen Tijun

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240205

      Abstract:The effects of the co-addition of Ni and Zn on the microstructure and mechanical properties of the extruded Mg-6.84Y-2.45Cu (MYC, wt.%) alloy were researched at room temperature. In addition to the α-Mg and Y-rich phases, the lamellar 18R-LPSO phase and granular Mg2(Cu, Ni, Zn) phase precipitated in the as-cast Mg-6.79Y-1.21Cu-1.12Ni-1.25Zn (MYCNZ, wt.%) alloy with the co-addition of Ni and Zn. During homogenization, a phase transformation occurred in the MYCNZ alloy, transitioning from the 18R-LPSO phase to the thin striped 14H-LPSO phase in the grain interior. After extrusion, the amounts, morphology, and distribution of the second phase were altered, and the grain size of the extruded MYCNZ alloy was significantly reduced to ~2.62 mm. Additionally, a weaker basal texture formed in the extruded MYCNZ alloy. The tensile results indicated that the co-addition of Ni and Zn significantly enhanced the tensile strengths of the extruded MYC alloy while maintaining good ductility. The tensile yield strength (σ0.2), ultimate tensile strength (σb), and elongation to failure (εL) of the extruded MYCNZ alloy were 266.9 MPa, 299.8 MPa, and 20.1%, respectively. The excellent tensile strength of the extruded MYCNZ alloy was mainly due to grain refinement and the second phase strengthening, while its outstanding ductility could be ascribed to the texture weakening and activation of non-basal slips.

    • WANG Xiaoxi, ZHANG Xiang, ZHANG Fei, XIA Xiaolei

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240213

      Abstract:A novel process named Expansion Equal Channel Angular Pressing (Exp-ECAP) which couples multiple forms of deformation such as upsetting, shearing, and extrusion into one was proposed. Ti/Al bimetallic composite rod was successfully fabricated by a single pass of Exp-ECAP process at 450 ℃ combined with post annealing heat treatment. The interface microstructure and bonding properties of Ti/Al bimetallic composite rod were investigated using SEM, EDS, XRD, EBSD and shear test. The results show that under the severe shear stress of Exp-ECAP process and the high-temperature annealing conditions, the Ti/Al bimetallic composite rod achieves good interfacial bonding quality, and a metallurgical bonding layer of approximately 1.27μm thickness is appeared through mutual diffusion of the titanium and aluminum matrix elements. New phases generated in the bonding interface layer are mainly intermetallic compound TiAl, and a small amount of inhomogeneous distributed Ti3Al (near the titanium side) and TiAl3 (near the aluminum side) are also contained. Moreover, a large number of equiaxed ultrafine grains are obtained in the Ti/Al interface bonding layer through phase transformation reactions and partial recrystallization, and the grains grow randomly without obvious preferred orientation. The shear strength of Ti/Al bimetallic composite rod is about 66.29 MPa, and shear failure mainly occurs in the TiAl phase layer, exhibiting brittle fracture characteristics.

    • Zhang Yuandong, Zhao Zhanglong, Cao Sheng, Feng Kaikai, Li Pu, Zha Xiaohui, Li Qian, Xin Shewei

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240214

      Abstract:The evolution of microstructure and tensile properties of Ti-5Al-6.5Mo-1.5Fe low-cost titanium alloy under different forging parameters was studied, and it was found that there is a significant correlation between the microstructure and properties of the alloy under different forging parameters.The results show that when the alloy is forged in α+β phase region, the content and size of the primary equiaxed αp phase in the microstructure decrease gradually with the increase of temperature, and the tensile strength and plasticity fluctuate slightly. As the forging deformation increases, the morphology of αp phase in the microstructure changes obviously, and the strength and plasticity of the alloy remain stable. There is a continuous accumulation of misorientation inside the αp phase to promote spheroidization and recrystallization. The orientation of β phase gradually transforms into the Cube texture {001}<100> under deformation force. When forged in the single β phase region, the alloy obtains coarse original β grains, the αp phase completely disappears, the intragranular secondary α phase (αs) increases, the long strip grain boundary α phase (αGB) precipitates, and the plasticity of the alloy drops sharply. The coexistence of equiaxed αp phase which can coordinate deformation and nanoscale αs phase which significantly improves the strength of the alloy in the microstructure can achieve high strength and high toughness at the same time, allowing the alloy to obtain better mechanical properties in α+β phase region. The β coarse grain is the main reason for the decrease of plasticity after forging in the single β phase region of the alloy, and the tensile fracture mechanism of the specimen changed from single dimple fracture after forging in α+β phase region to cleavage-dimple mixed fracture after forging in single β phase region.

    • LIU Jinsong, TANG Xujing, WANG Songwei, XIAO Yu, ZHANG Renwei, SONG Hongwu, ZHANG Shihong

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240215

      Abstract:Copper-chromium-zirconium alloy is widely used in communication electronics, rail transit, aerospace and other fields, and improving its strength and conductive properties is a research focus in recent years. In this paper, Cu-1Cr-0.1Zr and Cu-1cr-0.1zr-0.07La alloy ingots were designed and prepared, and treated by solution solution-warm rolling - cold rolling - pre-aging - cold rolling - aging process. The micro and micro structures of the two alloys were analyzed by optical microscope, scanning electron microscope and transmission electron microscope. The hardness and conductivity of the alloys were measured by microhardness tester and eddy current metal conductivity meter. The results show that after 400℃ warm rolling, a small amount of nanometer Cr phase with FCC structure is precipitated from the alloy matrix, the size is about 5nm. The primary Cr phase is distributed in spherical and rod-like form in grain boundaries and crystals, and rare earth La is wrapped in the outer layer of Cr phase to form a core-shell structure, which inhibits the growth of Cr phase. After 83% cold rolling +400℃×2h aging treatment, Cu-1cr-0.1zr-0.07La alloy reaches a peak hardness of 199.8HV, and the conductivity is 66.5%IACS, which is 20HV higher than that of Cu-1Cr-0.1Zr alloy, and the corresponding conductivity is 3.5%IACS lower. After further cold rolling at 44%, Cu-1cr-0.1zr-0.07La alloy reached the peak hardness of 212.9HV, tensile strength of 640MP and the conductivity of 74.4%IACS after aging at 400℃×4h, which was 17.2HV higher than that of Cu-1Cr-0.1Zr alloy, and the conductivity decreased by 4.7%IACS.

    • Dong Guowen, Wang Wenli, Zhao Di, Li Haoyang

      Available online:June 17, 2024  DOI: 10.12442/j.issn.1002-185X.20240218

      Abstract:In-situ alloying is an approach that employs compositional design to blend commercially available powders in specific ratios as feedstock for Selective Laser Melting (SLM) fabrication of alloy components, potentially addressing the challenges associated with the preparation of pre-alloyed powders. In this paper, Mg-3.4Y-3.6Sm-2.6Zn-0.8Zr multi-component rare-earth magnesium alloy bulk sample and melt track samples were prepared by SLM in-situ alloying method using Mg, Y, Sm, Zn, and Zr commercial powders as raw materials. The formability, relative densities, surface morphology, microstructure and microhardness of the samples under different process parameters were investigated and compared with the pre-alloyed powder-forming specimens. The results show that a single melt track can be obtained at a laser power of 80 W to obtain a stable and smooth melt track, and the melt pool is in conduction mode. The bulk sample has the maximum relative densities of 98.71% at a laser power of 80 W and a scanning speed of 300 mm/s, with the least pores and unmelted particles, and a microhardness of 98.97 HV.The physical phases of the in-situ alloyed samples are composed of the Mg matrix, Y-Zr-O rare-earth oxides, and the eutectic phase (Mg,Zn)3(Y,Sm), and the microstructures are mostly fine equiaxed crystals.

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    Latest number
    Rare Metal Materials and Engineering
    2024,Volume 53, Issue 5
    Editor in chiefPingxiang Zhang
    Associate editorYingjiang Shi
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