最新刊期
      卷 40 ， 期 10 ， 2020
      • Jiang Hongxiang,Sun Xiaojun,Li Shixin,He Jie,Zhao Jiuzhou
        Vol. 40, Issue 10, Pages: 1045-1049(2020) DOI: 10.15980/j.tzzz.2020.10.001
        摘要：Continuous solidification experiments have been carried out with Al-Bi alloys under a role of direct current.The effects of direct current density,alloy composition,solidification speed and conductivity of matrix liquid and dispersion phase on the solidification structure of immiscible alloys were investigated.The results demonstrate that a direct current shows great effect on the microstructure evolution in a continuously solidified immiscible alloy,which accelerate the minority phase droplets（MPDs）to migrate along the radial direction during the liquid-liquid phase change process.When the electric conductivity of MPD is lower than that of the matrix liquid,the MPDs is migrated from the center to the surface of the sample under the direct currents.When the electric conductivity of MPD is higher than that of the matrix liquid,the MPDs is migrated from the surface to the center of the sample.  
        关键词：Immiscible Alloy;Direct Current;Continuous Solidification;Spatial Migration   
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        发布时间：2023-12-18
      • Jiang Wenming,Li Guangyu,Guan Feng,Zhu Junwen,Yu Yang,Fan Zitian
        Vol. 40, Issue 10, Pages: 1050-1056(2020) DOI: 10.15980/j.tzzz.2020.10.002
        摘要：The effects of heat treatment on interfacial microstructure of solid-liquid compound Al/Mg bimetal processed by lost foam casting was investigated in order to explore the new process suitable for the Al/Mg bimetallic castings.The results reveal that the crack detect appears in the interface of the Al/Mg bimetal after homogenizing annealing+air cooling method,which is mainly attributed to the different expansion coefficient between matrix and intermetallic compound of the interface at a faster cooling rate,and the interface is easy to crack with large stress.While under the homogenizing annealing+furnace cooling condition,the interface is free of the crack defect,and a new diffusion layer composed by Al（Mg）solution+Mg2Si is formed between Al matrix and Al3Mg2+Mg2Si layer.With the increase of the homogenizing annealing time,the thickness of the new diffusion layer is constantly increased,and the grain size of theδ-Mg in the Al12 Mg17+δ-Mg eutectic is increased,and the Al12Mg17phase in the Mg matrix is dissolved into the primary phase continuously.Through multistep homogenizing annealing+aging treatment,interfacial microstructure and composition can be more uniform compared to the singlestep homogenizing annealing method,which induces the Al12Mg17phase in Mg matrix to precipitate with a fine lamellar structure.  
        关键词：Lost Foam Casting;Solid-Liquid Compound;Al/Mg Bimetal;Heat Treatment;Interfacial Layer   
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        发布时间：2023-12-18
      • Lu Ruopeng,Li Kun,Yao Keyu,Jiao Kai,Zhao Yuhong,Hou Hua
        Vol. 40, Issue 10, Pages: 1057-1061(2020) DOI: 10.15980/j.tzzz.2020.10.003
        摘要：Mg-8Zn-0.5Cu-xMn series alloys with different Mn content were prepared by electromagnetic induction smelting,and the effects of Mn on the microstructure and properties of the alloys were investigated.The results reveal that the as-cast alloy structure is mainly composed ofα-Mg+MgZn2 and MgZnCu phases.After the solid solution treatment,most of Zn elements are dissolved into the matrix and a small amount of Mg（Zn,Cu）2 phase remains at the grain boundary.After the two-stage aging treatment,the distribution of the second phase is more compact.With the increase of Mn content,the grain size of the alloy is obviously refined.When Mn content is increased to 1%,Mn elements in the alloy is agglomerated into Mn-enrichment particles.The as-aged Mg-8Zn-0.5Cu-0.5Mn alloy presents the satisifed comprehensive performance,and its yield strength,tensile strength and elongation reach up to 130 MPa,228 MPa and 6.8%,respectively.  
        关键词：Mg-Zn Alloy;Two-stage Aging;Microstructure;Mn Content;Mechanical Properties   
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        发布时间：2023-12-18
      • Vol. 40, Issue 10, Pages: 1062-1066(2020) DOI: 10.15980/j.tzzz.2020.10.004
        摘要：The influence of squeeze casting on the microstructure,casting defects and mechanical properties of Mg-14Zn-3Al was investigated by OM,XRD and SEM.The results show that the microstructure of as-squeezed Mg-14Zn-3Al alloy is composed ofα-Mg matrix,long blockτ-Mg32（Al,Zn）49 phase and granular or skeleton-likeε-MgZn phase.With the increase of the squeeze pressure,the microstructure of the alloy is refined and the quantity of the second phase is increased.Meanwhile,the casting defects in the alloy are inhibited,whose area fraction in the casting is sharply reduced from 15.67% to 0.81%.After squeeze casting treatment,the tensile strength and elongation of Mg-14Zn-3Al alloy can reach 218.1 MPa and 5.2%,respectively,which are much higher than those of gravity casting（192.6 MPa,1.2%）.  
        关键词：Mg-Zn-Al Alloy;Squeeze Casting;Microstructure;Porosity;Mechanical Properties   
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        发布时间：2023-12-18
      • Yu Shuangxi,Zhang Youshou,Xia Lu,Zhou Lei,YeJinrui,Liu Zhihong,Wu Jianbiao,Guo Jian
        Vol. 40, Issue 10, Pages: 1067-1071(2020) DOI: 10.15980/j.tzzz.2020.10.005
        摘要：The modification of the existing phosphate binders was carried out by adding phosphonic acid and adjusting water addition.Microwave with high heating efficiency and good heating uniformity was adopted as the heat source to solidify rapidly sand.The results show that it can improve the humidity resistance of the test specimen by adding phosphonic acid to the adhesive,and the tensile strength reaches up to 1.93 MPa under relative humidity of 55%.On the other hand,the addition of phosphonic acid can significantly reduce the viscosity of the adhesive,improving the sand fluidity to a certain extent.Water content of the phosphate binder has also significant effects on the bonding strength,viscosity,humidity resistance,sand fluidity,hardening speed and other properties of the adhesive.Meanwhile,the mechanism of humidity resistance was also analyzed.  
        关键词：Modification;Organic Phosphonic Acid;Humidity Resistance;Viscosity;Sand Fluidity   
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        发布时间：2023-12-18
      • Xiong Cong,Wang Jian,Zheng Haizhong,Ma Panpan,Li Guifa,Lu Shiqiang
        Vol. 40, Issue 10, Pages: 1072-1076(2020) DOI: 10.15980/j.tzzz.2020.10.006
        摘要：Ti2AlNb-based alloys fabricated by smelting and casting,powder metallurgy and laser additive materials were introduced.The problems encountered in the preparation of Ti2AlNb-based alloys were described.The laser additive manufacturing Ti2AlNb-based alloy and its surface heat treatment technology were mainly introduced.The research progress in mechanical properties and heat treatment process of Ti2AlNb-based alloys were reviewed,and the achievements in terms of microstructure and performance were explored.The problems to be solved in the research of Ti2AlNb based alloy and the main bottlenecks in the engineering application in the future were put forward.  
        关键词：Ti2AlNb Alloy;Laser Additive Manufacturing;Heat Treatment Process;Surface Strengthening   
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        发布时间：2023-12-18
      • Qian Dongling,Lu Fumin,Yu Zhongtu,Zhang Henghua,Yang Yitao
        Vol. 40, Issue 10, Pages: 1077-1082(2020) DOI: 10.15980/j.tzzz.2020.10.007
        摘要：It is conducive to reducing the weight of the automobile by using aluminum alloy instead of steel to manufacture automobile chassis components,thereby reducing automobile energy consumption and emissions,which is of great significance to the environment and energy protection.The research progress in cast aluminum alloys for automobile chassis was reviewed based on the investigation of at home and abroad.In the related research of cast aluminum alloys,the composition variation mainly consists of Si,Mg,Mn and Zn.The types,strengthening mechanism,research background and die-casting process of cast aluminum alloys for automobile chassis was briefly introduced,and the current status of its component design and heat treatment process research was elaborated in detail,which could provid a reference for subsequent research and development.  
        关键词：Automotive Chassis;Cast Aluminum Alloy;Light Weight;Heat Treatment;Mechanical Properties   
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        发布时间：2023-12-18
      • Lin Shaoyi
        Vol. 40, Issue 10, Pages: 1083-1088(2020) DOI: 10.15980/j.tzzz.2020.10.008
        摘要：The semi-solid rheomolding AZ91D auto tire active safety device parts were prepared.The effects of severe rolling friction on the semi-solid rheomolding AZ91D auto parts were analyzed by "the fatigue experiment" and "25 000 km road test of cars equipping with the sample parts" and "50 km road test of cars after sudden deflation of their tires".The results indicate that the heat generated by the severe rolling friction can increase the temperature of the parts sharply to increase the plasticity of the parts,which is responsible for the strain accumulation and shading holes at the crack tip of the semi-solid rheomolding AZ91D auto parts.Someα-Mg phases in the transient zone can be torn into thin strips about 110 nm in diameter or 31 nm sheets.The heat can cause the remelting of β-Mg17Al12 of the eutectic structure in the surface layer of the parts local firstly,and the molten liquid flows along long cracks at the fracture,so the content reduction of eutectic structure between the adjacentα-Mg phases can result in gaps of 700 to 2 700 nm.The hardness of part which failed at 36 km in the road test of cars after sudden deflation of their tires is decreased by 9.6%,and the maximum hardness position is moved 1 mm into the part,which are attributed to structure change in the surface layer and the high temperature annealing.  
        关键词：Friction;AZ91D Magnesium Alloy;Semi-solid Rheomolding;Auto Part   
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        发布时间：2023-12-18
      • Li Junhong,Wang Yu,Sun Yu,Sun Jue
        Vol. 40, Issue 10, Pages: 1088-1091(2020) DOI: 10.15980/j.tzzz.2020.10.009
        摘要：In order to obtain high-quality flange for reducer and save design cost,Finite Element Method（FEM）was used to simulate the squeeze casting process.The gating system was designed according to the predicted defect position,and the design result was simulated again.The rationality of process design was analyzed,and the reliability of simulation analysis result was verified by experimental test to determine the optimized scheme,which could provide a reference for mass production.  
        关键词：Squeeze Casting;Numerical Simulation;FEM;Experimental Verification   
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        发布时间：2023-12-18
      • He Yaoyao,Zhang Hang,Chen Zihao,Li Dichen
        Vol. 40, Issue 10, Pages: 1092-1098(2020) DOI: 10.15980/j.tzzz.2020.10.010
        摘要：The application and development of laser additive manufacturing,binder jetting,material jetting,light curing,and multi-material fusion deposition in multi-material additive manufacturing were described.The laser additive manufacturing technology was divided into four development stages:coating structure,gradient pore structure,functional gradient structure and multifunctional gradient coupling structure.The developing route of multi-material additive manufacturing technology was proposed.The application of multi-material additive manufacturing technology in terms of complex structure formation,multi-material collaborative manufacturing for multi-physical fields such as sound,light and electromagnetic,as well as application prospects for cutting-edge technology was put forward.  
        关键词：Multi-Material;Additive Manufacturing;Development Route;Application Prospects   
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        发布时间：2023-12-18
      • Hu Qiang,Yan Liangming,Du Qingchun,Xi Zhenjie,Li Xiaogang,Sun Jian
        Vol. 40, Issue 10, Pages: 1099-1103(2020) DOI: 10.15980/j.tzzz.2020.10.011
        摘要：A356 aluminum alloy was prepared by water-cooled die casting,and the hot deformation behavior of the alloy was analyzed by hot compression experiment.The stress-strain curve of the alloy was analyzed,and the constitutive equation was established,in addition,the hot working diagram was drawn.The results reveal that the flow stress of the alloy is increased with the increase of strain rate and the decrease of deformation temperature.It is also found that the softening mechanism of the alloy during thermal deformation is characterized by mainly dynamic recovery.At the same time,the average thermal deformation activation energy Q is calculated to be 238.6 kJ·mol-1.Through the hot working diagram and microstructure analysis of the alloy after hot compression,it is found that the alloy presents the satisfied hot workability at 330～380℃and 5～10 s-1.  
        关键词：Water-Cooled Die-Casting;Dynamic Recovery;Constitutive Equation;Thermal Processing Map   
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        发布时间：2023-12-18
      • Cui Enqiang,Liu Yingzhuo,Sun Hao,He Kai,Wang Xianfei,Deng Xiaoliang,Qin Kang,Qin Jieqing
        Vol. 40, Issue 10, Pages: 1103-1106(2020) DOI: 10.15980/j.tzzz.2020.10.012
        摘要：In view of the structure and technical difficulties of large heat-resistant magnesium alloy shell castings,the casting process was analyzed,including system design,sand core and chilling system design.The casting process was simulated by the ProCAST software,and the casting defects were simulated to understand the causes,and the countermeasures were determined and secondary simulation verification was carried out.According to the simulated results,the casting process parameters were optimized.The results show that the gating system has stable filling and good feeding.The shell castings with good quality were produced by low pressure casting.  
        关键词：Heat Resistant;Magnesium Alloy;Shell;Low Pressure Casting   
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        发布时间：2023-12-18
      • Chen Jianhong,Nie Junyi,Zeng Qingjie,Li Weihao
        Vol. 40, Issue 10, Pages: 1107-1109(2020) DOI: 10.15980/j.tzzz.2020.10.013
        摘要：Due to the existence of mold closing gap during die-casting forming process,die-casting parts is easy to form flash and burr.Traditional manual operation to remove flash and burr usually requires a large amount of manpower with the high and strict skill.The surface polishing workstation of industrial robot is a good attempt to solve the above problems.The application results show that the demonstration production line using the surface polishing workstation of industrial robot can realize 1 person and 1 line,polishing 180 pieces of mass production in7 hours per shift,with a cycle of 180 seconds per piece.  
        关键词：Industrial Robot;Die Casting;Polishing Surface Station   
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        发布时间：2023-12-18
      • Zhong Jianwei,Sheng Guofu,She Guifeng,Xie Zhigang,Yu Guoyan,Wang Huisheng
        Vol. 40, Issue 10, Pages: 1110-1113(2020) DOI: 10.15980/j.tzzz.2020.10.014
        摘要：New fuel assembly bottom nozzle was manufactured with austenite duplex stainless steel containing 10% to 30% ferrite.According to the bottom nozzle characteristics and the technical requirements,the investment casting process was adopted.The results show that new fuel assembly bottom nozzle is produced successfully by optimizing the gating system,selecting the imported photopolymer resin with low thermal expansion coefficient as the raw material for the wax model,strictly controlling the slurry ratio and viscosity in casting surface coating stage,cleaning the shell with alkali boiling and core removal,and other improved casting processes.  
        关键词：Bottom Nozzle;Investment Casting;Process Control   
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        发布时间：2023-12-18
      • Kong Youshun,Li Fei,Si Jinmei,Mao Changcheng,Wang Jianjun
        Vol. 40, Issue 10, Pages: 1113-1117(2020) DOI: 10.15980/j.tzzz.2020.10.015
        摘要：The fracture origination of investment casting aluminum alloy component was analyzed and detected mainly through the aspects of macrostructure,microstructure,modification effects and mechanical properties.The results show that the fracture mode is characterized by brittle fracture,and the fracture is located at the thinnest part,where exist a great stress concentration.As for the material,the plasticity and fatigue resistance of the material are decreased due to inadequate modification and dendrite shrinkage  
        关键词：Aluminum Alloy;Investment Casting;Fracture Failure   
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        发布时间：2023-12-18
      • Li Bobo,Yuan Bingbing,Yang Guang,Liu Yinqi,Ma Yi
        Vol. 40, Issue 10, Pages: 1118-1120(2020) DOI: 10.15980/j.tzzz.2020.10.016
        摘要：Domestic titanium and titanium alloy castings are mainly produced by machined graphite and investment precision casting.However,subject to technical limitations,the actual production process can’t fully satisfy customers’ demand of high quality,low cost and short delivery time.Therefore,it is rather necessary to promote the research and application of new casting technology,thus complementing with the existing technology.Lost foam casting has advantages over other casting methods,which has been widely used in metal castings such as steel,aluminum,etc.,yet rarely reported in titanium alloys.The advantages and application prospects of titanium alloy were reviewed to provide reference for EPS lost foam cladding casting technology.  
        关键词：Titanium Alloy;Lost Foam Casting;Cladding Casting   
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        发布时间：2023-12-18
      • Du Mingzhe,Wang Jiefang,Zhang Yunjie,Yang Ruibin,Zhang Guopeng,Liu Zhongxia,Cai Bin
        Vol. 40, Issue 10, Pages: 1121-1126(2020) DOI: 10.15980/j.tzzz.2020.10.017
        摘要：The high temperature creep properties and microstructure of 2024 aluminum matrix composites containing Sc were investigated,which was reinforced by copper coated short carbon fiber（Cf）with different lengths（2,3,4,5 mm）and the same content（3%）.The results show that the creep behavior of 2024 containing Sc composites reinforced by 2 mm carbon fiber is optimized under the creep condition of 200℃and 300 MPa,where the creep fracture time is 21.16 hand steady creep rate is 1.05×10-5 s-1.The creep observation at different temperatures（150～190 ℃）and different stresses（200～400 MPa）shows that threshold stress of composites is decreased linearly with increasing in temperature,and 2024 containing Sc composites reinforced by 2 mm carbon fiber has the highest creep activation energy of 83.9 kJ/mol.The main creep mechanism of 2024 containing Sc aluminum matrix composites reinforced by short carbon fiber is characterized by dislocation climbing.  
        关键词：Aluminum Matrix Composites;Short Carbon Fiber;Aging;Creep   
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        发布时间：2023-12-18
      • Lin Chunmei,Wang Yujin,Xu Weiliang,Yang Chao,Qin Fangcheng
        Vol. 40, Issue 10, Pages: 1126-1130(2020) DOI: 10.15980/j.tzzz.2020.10.018
        摘要：The liquid-liquid composited casting was used to produce 2024/6061 aluminium casting blank.The microstructure characteristics of the bimetallic casting blank with different pouring interval time was investigated.The evolution of the interfacial microstructure,element diffusion laws and bonding properties were analyzed.The interface bonding mechanism of the bimetallic blank was described.The results show that the composited casting blank bonding with different interval time is characterized by metallurigical,and the bonding interface is clear and sound.The Mg,Si,and Cu elements on both sides of the interface are diffused to some extent,where Si has the farthest diffusion distance.When the interval time is 20 s,the composite blank is characterized by the completed metallurgical bonding,and the bonding properties are between those of 2024 and 6061 alloys.The hardness,yield strength,tensile strength and elongation are 88.7 HV,193.4 MPa,290.4 MPa and 20.8%,respectively.  
        关键词：Aluminum Alloy;Bimetallic Blank;Liquid-liquid Composited Casting;Pouring Interval Time;Binding Properties   
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        发布时间：2023-12-18
      • Qin Yiming,Zhuang Linzhong,Meng Zhibao,Chen Zhennan,Tang Xin
        Vol. 40, Issue 10, Pages: 1131-1134(2020) DOI: 10.15980/j.tzzz.2020.10.019
        摘要：The effects of molten pool depth on H solubility in Al-melt under the coupling of gravity and vacuum condition were calculated.The results reveal that the H solubility is decreased with the decrease of molten pool depth and temperature and the increase of vacuum degree,while the H solubility for theoretical calculation were lower than that in actual measurement,which may be attributed to the uneven H concentration in the depth direction and the existence of H-gas bubbles.By controlling the degree of vacuum and the depth of molten pool,the lower H solubility can be achieved,and the theoretical range of the vacuum degree and the bath depth of Al-melt is suggested for the H solubility less than 0.2 mL/100 g.  
        关键词：Vacuum;Hydrogen;Pressure;Molten Pool Depth;Solubility   
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        发布时间：2023-12-18
      • Zhou Sipeng,Sun Youping,He Jiangmei,Yang Chunyang
        Vol. 40, Issue 10, Pages: 1134-1138(2020) DOI: 10.15980/j.tzzz.2020.10.020
        摘要：2524 aluminum alloy was carried out by optical fiber laser welding test and the influence of welding speed on the microstructure and mechanical properties of optical fiber laser welding joint was investigated by means of microstructure analysis,X-ray diffraction,tensile and hardness testing.The results illustrate that the welding speed has a significant effect on the joint.With the low welding speed,the heat input will be increased so that the weld joint can be collapsed.On the contrary,the lack of heat input will result in the joint welded incompletely.With the decrease of heat input,the weld width is decreased gradually,and the size of equiaxial dendritic crystals in the center of the weld is decreased,and the area of columnar dendritic crystals in the fusion zone becomes narrower.Meanwhile,the dendritic spacing is decreased,and the growth direction is enhanced.In the unidirectional tensile testing,the tensile strength of the joint is increased with the increase of welding speed,and it reaches up to the maximum value of 329.21 MPa at 75 mm/s,which is 73.15% of the base metal.The hardness curve of the joint presents U-shaped distribution,and the softening presents the most severe in the weld center.  
        关键词：Aluminum Alloy;Laser Welding;Mechanical Properties;Microstructure   
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        发布时间：2023-12-18
      • Wang Xin,Jiang Feng,Liu Xiangling,Niu Yu,Wang Yijian
        Vol. 40, Issue 10, Pages: 1139-1143(2020) DOI: 10.15980/j.tzzz.2020.10.021
        摘要：The hypoeutectic Al-6.34Mg-3.66Si is mainly used in the light-weight materials,however,the coarse Chinese script Mg2Si phase will seriously fracture the Al Matrix.Therefore,the effect of melt superheating temperature and time on the microstructure and mechanical properties of hypoeutectic Al-6.34Mg-3.66Si was investigated.The results show that with the superheat temperature at 850 ℃ for 25 min,the primary-Al phase is changed from fishbone-like dendrite to fine equiaxed crystal,and the thick lamellar Mg2Si is completely changed into fine fibrous with uniform distribution.The size of Mg2Si is decreased from 3.02μm to 0.97μm,which is 67.9% smaller than that of the original alloy.The tensile strength is increased by 34.4%,and the fracture mode is converted from the original brittle fracture to the combined one,presenting good plasticity.  
        关键词：Hypoeutectic Al-6.34Mg-3.66Si;Melt Superheating;Microstructure;Mechanical Properties   
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        发布时间：2023-12-18
      • Zhu Zhenfeng,Liang Pengguang,Sun Youzheng,Liang Xiaoning
        Vol. 40, Issue 10, Pages: 1143-1146(2020) DOI: 10.15980/j.tzzz.2020.10.022
        摘要：The properties of 7150 aluminum alloys in T6 and RRA states were analyzed by means of Vickers hardness test,conductivity test and tensile as well as intergranular corrosion testing.The effects of regression time on the microstructure of 7150 aluminum alloy in RRA state were investigated by optical microscopy（OM）and transmission electron microscopy（TEM）.The results show that the 7150 aluminum alloy presents higher strength with poor intergranular corrosion resistance.With the increase of regression time,the intergranular corrosion resistance of the 7150 alloy in RRA state is increased,while the strength is first increased and then decreased.When the regression time is 1 h,the main precipitate in the grain is GP area,accompanied with fine precipitateη′,which is distributed uniformly with the size of several nanometers.The precipitation phase at grain boundary is large and discontinuous with obviously precipitate free zone.The 7150 alloy treated at T6+185℃×1 h+T6 possesses both high strength and good intergranular corrosion resistance,presenting the optimal comprehensive performance.  
        关键词：7150 Aluminum Alloy;Regression Time;Intergranular Corrosion Resistance;Microstructure   
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        发布时间：2023-12-18
      • Wang Xinyu,Gao Yang
        Vol. 40, Issue 10, Pages: 1147-1151(2020) DOI: 10.15980/j.tzzz.2020.10.023
        摘要：Ti-6Al-4V alloy was prepared by compression molding+vacuum sintering process.The effects of sintering temperature on the relative density,microstructure,phase composition and hardness of the alloy were systematically investigated with the help of OM,SEM,EDS,XRD,hardness tester.The results show that when the sintering temperature is 1 035℃and 1 100℃,the microstructure of the alloy is composed of equiaxedαgrains and intergranularβphase.When the sintering temperature is 1 150℃,the microstructure presents bimorphic and contains equiaxedαgrains,lamellar alpha grains and a small amount of intergranular beta phase.At the sintering temperature of 1 200 ℃ and 1 300 ℃,the microstructure contains a large number of lamellar alpha grains and small short rod-shaped alpha grains.When the sintering temperature is above 1 100℃,vanadium is almost absent in theαphase in the sample.As the sintering temperature increases,the ambient gas is more likely to invade the sample to form interstitial solid solution.When the sintering temperature is 1 300 ℃,the oxygen content in the sample reaches 0.507%.With the increase of sintering temperature,the densification process of the sample is accelerated,and the relative density of Ti-6Al-4V alloy sintered reaches 97.878% at 1 300℃.Due to the ascension of densification and the increase of interstitial elements,the hardness of Ti-6Al-4V alloy is increased with the sintering temperature increasing.  
        关键词：Compression Molding;Ti-6Al-4V Alloy;Microstructure;Relative Density   
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        发布时间：2023-12-18
      • Xiao Jiangbo,Yao Junping
        Vol. 40, Issue 10, Pages: 1152-1155(2020) DOI: 10.15980/j.tzzz.2020.10.024
        摘要：The idea work of adhesion,density of state（DOS）and Millken charge distribution of TiC（111）/Mg（0001）interfaces with alloying elements（Al,Zn,Cu）were investigated by the plane wave pseudopotential method based on the first-principle density functional theory（DFT）to understand the effects of doping alloy elements（Al,Zn,Cu）in Mg Matrix on the stability of TiC（111）/Mg（0001）interface.The results show that for the ideal TiC（111）/Mg（0001）interface,the C-terminated center-site interface is the most stable after geometric optimization.When adding alloy elements（Al,Zn,Cu）to different positions in Mg phase,the idea work of adhesion,partial density of states and Millken charge distribution of the interfacial atoms,are changed in different degree.When doped atoms are in the non-interfacial layer,adhesion work has slight change,which has slight effect on the stability of TiC（111）/Mg（0001）interface.And when the doped atoms are in the interface layer,adhesion work has significant change,where the doped Al atoms and Cu is beneficial to improving the wettability of TiC（111）/Mg（0001）interface,enhancing the stability of the interface,with the satisfied effect of Al atom.Moreover,doped Zn atoms mainly combine with other atoms through metallic bonds instead of interfacial covalent bonds,resulting in a decrease in the adhesion work of the interface,which is adverse to improving the interface wettability.  
        关键词：Alloy Element;TiC/Mg Composites;Interface;First-principle   
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      • Zhong Mingjun,Wang Kelu,Lu Shiqiang,Li Xin,Zhou Xuan,Feng Rui
        Vol. 40, Issue 10, Pages: 1156-1160(2020) DOI: 10.15980/j.tzzz.2020.10.025
        摘要：The isothermal constant strain rate compression test of the forged TC20 titanium alloy was carried out by using Gleeble-3800 thermal simulator.The change of flow stress at 940～1 030℃and strain rate of 0.001～10 s-1 was investigated.According to the experimental data,the temperature-increment value under different deformation conditions was calculated,and the features of deformation heat generation were analyzed.Based on the superposition diagram of strain rate sensitivity exponent m contour map and instability map,the influence of thermal deformation parameters on the local flow behavior of the TC20 titanium alloy was analyzed combined with the verification of microstructure observation.The results show that the flow stress of TC20 titanium alloy is decreased with the increase of the deformation temperature and increased with the increase of the strain rate.The temperature-increment caused by the deformation heat effect is increased with the increase of the strain rate and decreased with the increase of the deformation temperature.With deformation at 940～990℃and high strain rate of 0.32～10 s-1,the alloy is prone to local flow with the deformation temperature decreasing and the strain rate increasing.  
        关键词：TC20 Titanium Alloy;Deformation Heat Effect;Strain Rate Sensitivity Exponent;Local Flow   
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      • Kong Lingbao,Zhou Yanjun,Song Kexing,Feng Cunli,Kang Junwei,Cao Jun,Li Zhou,Niu Liye,Guo Huiwen
        Vol. 40, Issue 10, Pages: 1160-1163(2020) DOI: 10.15980/j.tzzz.2020.10.026
        摘要：The effects of drawing deformation and heat treatment on the conductivity,mechanical properties and microstructure of Cu-Ag alloy prepared by hot horizontal continuous casting were investigated contractively.The results show that the alloy can obtain excellent comprehensive properties within the test range by applying 85.9% drawing deformation between solution and aging heat treatment.The electrical conductivity,microhardness,tensile strength and elongation reach 51.91 MS/m,169.7 HV0.1,541.6 MPa and 15.5%,respectively.The alloy grains can be refined and arranged in a specific direction by applying drawing deformation between solid solution and aging treatment.Meanwhile,the tensile fracture morphology is dominated by uniformly distributed dimples,and the fracture surface is relatively flat.  
        关键词：Cu-Ag Alloy;Drawing Deformation;Heat Treatment;Electrical Conductivity;Microstructure   
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      • Gao Shuai,Zhao Junsheng,Zhang Guodong,Li Chunjian,Cao Zhijuan,Xue Shuangqiao
        Vol. 40, Issue 10, Pages: 1164-1167(2020) DOI: 10.15980/j.tzzz.2020.10.027
        摘要：Based on Simufact software,the three-dimensional elastic-plastic FE model of cold and hot spinning of CuSn8 Palloy cylinder was established.The reliability was validated by experiments,and the variation of spinning force and the distribution of stress and strain in the large plastic deformation zone were analyzed.The results indicate that the radial spinning force is the primary driving force of the spinning forming,followed by the axial force,and the tangential force is the mininum value.The maximum value of the equivalent stress always appears in the three-wheel operating area,while the equivalent plastic strain always presents a gradient distribution that both ends are increased towards the middle in the axial direction and its maximum value is located at the formed zone.With the fixed other parameters,the values of spinning force and equivalent stress in hot spinning forming are less than those in cold spinning,while the equivalent plastic strain is the reverse.  
        关键词：Simufact;CuSn8P Alloy;Spinning   
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        发布时间：2023-12-18
      • Ma Ding,Huang Guoping,Liu Haiding,Yang Xianjun,Cai Xinnan
        Vol. 40, Issue 10, Pages: 1168-1171(2020) DOI: 10.15980/j.tzzz.2020.10.028
        摘要：The VIM+ESR+VAR triplex melting process was adopted to produce the Ni-Cr resistance alloys and the purity variation was analyzed comparing with VIM+ESR double process products.The results reveal that the reduction of harmful elements and nonmetallic inclusion in triplex melting process products reach up to 50%.Meanwhile,the trial-produced alloy has a better machining performance,which meets the requirements for processing Ni-Cr precision resistance alloy foil.  
        关键词：Triplex Melting Process;Precision Resistance Alloy;Purity   
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        发布时间：2023-12-18
      • Zhang Hui,Li Xingguo,Guo Guqing,Wu Wei,Chang Chao
        Vol. 40, Issue 10, Pages: 1172-1176(2020) DOI: 10.15980/j.tzzz.2020.10.029
        摘要：The crystal structure types of FeAlxNiCrMn high entropy alloy were analyzed by the solid solution characteristic parameters and the first principle,and the effects of Al content on the crystal structure and mechanical properties of FeAlxNiCrMn high-entropy alloy was investigated.From the aspects of calculation of solid solution characteristic parameters,energy analysis,and stability criterion of material mechanics,it is found that FeAlxNiCrMn（x=0,0.25,0.5,0.75,1）high-entropy alloy mainly exists in a single face-centered cubic solid solution structure.The results reveal that the lattice constant of FeAlxNiCrMn alloy is gradually increased with Al content increase,and the melting point and hardness of the alloy is first increased and then decreased.When x=0.75,the elastic modulus and shear modulus of the alloy will be more than those of other FeAlxNiCrMn alloys（x=0,0.25,0.5,1）.When x=0.25,the bulk modulus of the alloy reaches the maximum value.Meanwhile,the plasticity of FeAlxNiCrMn alloy is decreased gradually with increasing in Al content.The molar content of 0.5 is not only the critical value for the alloy to change from toughness to brittleness,but also from elastic anisotropy to elastic isotropy.  
        关键词：First Principle;High Entropy Alloy;Crystal Structure;Mechanical Properties   
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