最新刊期
卷 37 ， 期 9 ， 2017
- 摘要：The precipitation behavior of the 7050 thick sheet during the RRA process at 185 ℃ was analyzed by tensile test,conductivity test and transmission electron microscopy（TEM）observation,and it was compared with that of 7050-T6 ones.The results indicate that 7050-T6 alloy possesses high strength,such as the yield strength of 507 MPa,and low stress corrosion resistance,such as low conductivityof 16.59 MS/m.During the retrogression process,strength of the alloy is increased firstly and then decreased with the increase of electric conductivity through the whole process.As retrogressed at185 ℃for 1h,the 7050-RRA exhibits excellent comprehensive performance,where yield strength is increased to 523 MPa and electric conductivity is 20.07 MS/m.The TEM observation reveals that the main strengthening phase is GP（I）zone andη′in the 7050-T6 alloy.During the RRA process,the GP（I）zone is transformed into GP（Ⅱ）zone andη′,and the further precipitation ofη′results in the strength increase to a peak value.Then,retrogressed to 4h,the GP zone disappears and the transition ofη′→ηcauses the decrease of strength.关键词：7050Alloy;Retrogression and Re-Aging（RRA）;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：1145casting plates with 7mm in thickness have been manufactured with electrolytic aluminum liquid.Effects of different casting speeds（9001 400 mm/min）on the microstructure and the center layer segregation in cast-rolling plates were investigated and analyzed by means of optical microscope（OM）,scanning electron microscope（SEM）and energy disperse analysis techniques（EDS）.The results reveal that casting speed has important effect on microstructure of 1145 aluminum plates.When the roll casting speed is in range of 9001 200mm/min,with increasing in casting speed,change of the grain size along the longitudinal section of the cast-rolling plate can be ignored with the fine and uniformly distributed grain,and the center layer is free of segregation.With the casting speed more than 1 300mm/min,the grain begains to be coarsen and the segregation is more serious.Someβ-FeSiAl compounds are precipitated from the segregation layer.To obtain the cast-rolling plate with fine grain and free composition segregation,the optimum experimental casting speed is in range of 9001 200mm/min.关键词：Casting Speed;1145 Aluminum;Cast-rolling Plate;Microstructure;Center Layer Segregation
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发布时间：2023-12-18 - 摘要：<正>2017年8月25日,忠旺宣布完成该公司首宗海外并购。其间接全资附属公司忠旺铝业德国有限公司通过收购获得德国乌纳铝业股份有限公司（"乌纳铝业"）99.72%的股权。据了解,乌纳铝业成立于1914年,主要产品为无缝管、分流挤压管以及其他高附加值铝合金挤压产品,应用于航空和汽车工业等领域,主要客户包括空客、波音、庞巴迪、奔
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发布时间：2023-12-18 - 摘要：Effects of different solid solution and aging treatment on microstructure and mechanical properties of IMI834 Ti alloy were investigated to understand the relation of solid solution and aging treatment with microstructure and properties of the alloy as well as the optimized heat treatment parameters.The results reveal that with increasing in solid solution temperature,tensile strength and yield strength of the alloy exhibit increased firstly and then decreased in form of parabolic.The maximum strength and elongation of the alloy can be observed in range of 1 0051 025 ℃.The room and elevated strength as well as elevated contrac-tion of area are increased firstly and then decreased with increasing in aging temperature.Elongation and ambient contraction of area is increased slightly firstly and then decreased slightly.Microstructural evolution of alloy can be ignored with increasing in aging temperature.During tensile crack process,crack is generated at theαphase.The optimized heat treatment process for the asforged IMI834 alloy is presented as follows:solid solution at（1 0051 025 ℃）×2 h+ water quenching+aging at（750800 ℃）×2h +air cooling.关键词：IMI834Titanium Alloy;Solid Solution Temperature;Microstructure Evolution;Tensile Properties
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发布时间：2023-12-18 - 摘要：By adopting four extrusion temperature,three extrusion ratio and three extrusion speed,effects of extrusion temperature and extrusion ratio as well as extrusion speed on the properties and microstructure of Gr.38 titanium alloy were investigated.The results reveal that the extrusion parameters have significant influence on the microstructure of Gr.38（ATI425）titanium alloy.With increasing in the extrusion temperature and extrusion ratio as well as extrusion speed,volume fraction ofαphase is decreased,and primaryαphase is recrystallized more fully,which is transformed from the distorted elongated shape gradually into spherical ones.Meanwhile,strength of the alloy is declined slightly with slightly rising of the elongation,which is attributed to more and more deformation thermal and deformation energy stored in the alloy resulting in the dynamic recovery and recrystallization.The optimized extrusion parameters of Gr.38 titanium alloy are presented as follows:extrusion temperature of 900930℃,extrusion ratio of 1418and extrusion speed of 7080mm/s.关键词：Gr.38 Titanium Alloy;Extrusion Parameters;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Hot compressive characteristics of 6061 aluminum alloy were investigated on Gleeble-3500 thermal simulation machine by performing isothermal compression tests at 300450 ℃ and 0.0110s-1 with the maximum reduction of 60%.The flow stress behavior of 6061 aluminum alloy at high-temperature was analyzed and the hot processing map was established based on the dynamic material model（DMM）.Moreover,the hot deformation mechanism was described according to the associated microstructure observation.The results show that the flow stress is decreased by increasing in the deformation temperature and decreasing in the strain rate,and the main softening mechanism of 6061 aluminum alloy is characterized by dynamic recovery.The instability zones of flow behavior appear widely at higher strain rate on the processing map.The optimum process interval of 6061 aluminum alloy for hot working is the deformation temperature at 430450℃and strain rate of 0.010.05s-1,in which some recrystallized grains canbe observed.关键词：6061 Aluminum Alloy;Hot Compressive Deformation;Flow Stress;Hot Processing Map
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发布时间：2023-12-18 - 摘要：The investment casting process of double metal cracking connecting rod was analyzed by designing side-pouring ways,and filling and solidification process was simulated by ProCAST software.Meanwhile,the orthogonal experiment method was used to optimize the process parameters,and cracking connecting rod was produced success fullg.The results show that in side gating system,sprue can play agood feeding effect,where only shrinkage porosity can be observed in the sprue cup and SPR.With the pouring temperature of 1 600℃,mould preheating temperature of 1 200℃,the cracking material preheat temperature of 500℃,shell mold is baked ahead,and then the cracking material is inserted to pour,so two kinds of materials with good bonding can be produced,meeting production requirement.关键词：Cracking Connecting Rod;Investment Casting;Numerical Simulation
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发布时间：2023-12-18 - 摘要：AuSn20 solder is widely used in the areas of high reliability microelectronic devices and optoelectronic devices packaging due to its excellent comprehensive properties.However,the coarse as-cast microstructure and inhomogeneous distribution of primary phase can result in the brittleness of the AuSn20 alloy,so it is difficult to prepare.Research of the preparation technology for the AuSn20 solder has been one of current hotspots.The principle and characteristics to prepare AuSn20 alloy solder using solid forming technology,liquid forming technology,thin-films technology and rapid solidification technology were reviewed,and the development direction of the preparation technology for the AuSn20 solder were also pointed out.关键词：AuSn20 Solder;Brittleness;Preparation Technology;Rapid Solidification
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发布时间：2023-12-18 - 摘要：The aluminum content in Mg-Al-Zn alloy was designed and analyzed by considering rheological behavior of semi-solid billet and corrosion resistance.The results reveal that when Al content is in range of 6% 11% and the solid fraction is increased from 30%to 60%,with increasing in Al content,the temperature sensitivity of alloys is decreased and solidification temperature range is narrowed.On the other hand,the corrosion resistance demonstrates that at the same solid fraction,with increasing in solid particle amount and decreasing in solid particle size,corrosion at the initiatory stage is accelerated,however,corrosion amount is decreased.With Al content of 8%,the Mg-Al alloy can form continuousβphase,which inhibits effectively the internal corrosion of semi-solid magnesium alloy.When Al content is in range of 8% 11%,it is suitable for the rheological requirement and improvement of corrosion resistance of semi-solid Mg-Al-Zn alloy.关键词：Mg-Al-Zn Alloys;Semi-solid;Composition Design
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发布时间：2023-12-18 - 摘要：The design idea of crucible radius was proposed,and influence of crucible radius on the magnetic flux density and electromagnetic force distribution of semisolid A356 aluminum alloy slurry was investigated.The change of magnetic flux density and electromagnetic force along the radius of the crucible for semisolid A356 aluminum alloy was simualted by ANSYS 15.0.The simulated results show that the magnetic flux intensity is increased from the center to the distance about 0.85 times of the crucible radius,decreased sharply and then increased near the edge.The electromagnetic force is increased with the increase of the crucible radius,and the increment-amplitude is larger and larger.The electromagnetic force is increased from the center to the distance about 0.9times of the crucible radius,decreased sharply at the edge.The experimental results of different crucible radius were compared with the simulated ones.The results reveal that the optimum crucible radius is 30 mm in the preparation of high quality semisolid aluminum alloy slurry.关键词：Crucible Radius;ANSYS;Electromagnetic Stirring;Magnetic Flux Density
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发布时间：2023-12-18 - 摘要：The SiC particle preform was prepared by 3D printing,and the SiC reinforced A356 matrix composites（SiCp/A356composites）were prepared by pressure infiltration technology.The microstructure and phase of SiCp/A356 composites were analyzed by optical microscope（OM）,scanning electron microscope（SEM）,energy dispersive spectroscope（EDS）,X-ray diffraction（X-ray）and other modern analysis methods.The results reveal that the microstructure of SiCp/A356 composites fabricated by above-mentioned methods exhibits compact with uniformly distributed SiC particles in the A356 matrix and the desirable interface bonding.Moreover,the interfacial reaction is well controlled.As a result,some harmful phases such as Al4C3 brittle phase are absent from interfacial reaction products.Elements Si in the A356 alloy can prevents the formation of Al4C3 brittle phase,and the existence of Mg in the A356 alloy can improve significantly the wettability of SiC with A356.关键词：3DPrinting;SiCp/A356;Microstructure;XRD
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发布时间：2023-12-18 - 摘要：Through adopting 3D printing and Drop-On demand injection,taking the casting wax as the material,printing precision of the wax pattern was investigated to understand effects of wax spray temperature,molding speed and feed pressure based on numerical simulation and experiment.The optimum combination of process parameters was presented by orthogonal test.Then the spraying model theory was analyzed.Meanwhile,the fluid at the nozzle of the piezoelectric jet valve was simulated and analyzed,and influence of the process parameters was determined.The dimension precision of the wax pattern was obtained by 3D scanning,which verified manufacture feasibility of wax pattern.关键词：Wax Mold;lnjection Molding;Process Parameters;Dimensional Accuracy
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发布时间：2023-12-18 - 摘要：The high vacuum die casting process of the automobile chassis structual part was introduced,and effects of different heat treatment on the mechanical performance of the structural part were investigated.The results indicate that the strength of the part can be improved greatly by T5 treatment,where the tensile strength and yield strength can be increased by 24%and by 45%,respectively,while the ultimate tensile strength can be deceased by T6 treatment,however the ductility of the part can be improved to 8.4%.The strength and ductility of the part can be enhanced by T7 treatment,where the yield strength can be increased by 53%,and the elongation can reach 9.1%.关键词：Automobile Chassis Structural Part;T6 Treatment;T7 Treatment;Mechanical Performance
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发布时间：2023-12-18 - 摘要：ZL111aluminum alloy scroll plate of the automotive refrigeration compressor was produced by squeezing casting.The effects of process parameters on mechanical properties and microstructure of the scroll plate were investigated by the single variable method.The results reveal that the castings have absence of casting defects with dense microstructure and satisfied comprehensive mechanical properties in the optimum process parameters（casting pressure of 100 MPa,holding time of 16 s,pouring temperature of 740 ℃）.The tensile strength,elongation and hardness of aluminum alloy scroll plate specimen can reach 370 MPa,2.5% and 128 HB,respectively.关键词：Aluminum Alloy;Scroll Plate;Squeezing Casting;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：According to the structural characteristics of aluminum alloy base,the gating system of die casting was designed.The filling of casting process was visualized by using Flow-3Dsoftware.According to the distribution of temperature,distribution and content of entrapped-air were predicted during casting filling process.The simulated results were analyzed and then 8overflowing slots were set at the place with serious entrapped-air.The simulated results reveal that the temperature difference of casting surface is decreased and the entrapped-air mainly exists in the overflowing slots.The filling process exhibits more stable and smooth.The surface of practical casting exhibits desirable,and the casting defects are reduced with improvement of the air tightness.关键词：Base;Die Casting Process;Numerical Simulation;Casting Defects
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发布时间：2023-12-18 - 摘要：<正>镁电池提供了保证现代生活安全的承诺,它与传统的锂离子电池不同,它们不易燃,也不容易爆炸,但是储存能量的能力有限。发表于《自然·通讯》杂志上的文章带来了电池阴极的新设计,极大地提高了存储容量,并颠覆了传统观点。中科院研究人员姚炎在报告中指出,他们将纳米结构的阴极和对镁电解质的新认识结合在一起,这项工作早在2014年已经开始进行,历时数年。
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发布时间：2023-12-18 - 摘要：<正>深圳市长盈精密技术股份有限公司（"长盈精密"）发布公开发行可转换公司债券预案,拟募资16亿元用于"智能终端零组件"和"新能源汽车零组件"项目并补充流动资金,以迎合智能终端、新能源汽车行业快速发展对精密组件的需求。近年来,以智能手机为代表的消费电子终端迅速发展。据IDC统计数据,全球智能手机出货量已由2009年的1.74亿部增长至2016年的14.7亿部,预计2017年全球智
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发布时间：2023-12-18 - 摘要：<正>据海关总署统计数据,17月中国共出口各类镁产品28.38万吨,同比增加29.95%,累计金额6.54亿美元,同比增加26.81%。其中,镁锭共出口15.22万吨,同比增加40.13%;镁合金共出口7.51万吨,同比增加10.83%;镁粉共出口5.10万吨,同比增加40.22%。
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发布时间：2023-12-18 - 摘要：<正>锂空气电池因具有超高的理论能量密度而被认为是电动汽车的潜在动力电源。锂氧电池的放电产物过氧化锂（Li2O2）具有绝缘、不溶的特性,因此,随着放电的进行,电极表面会逐渐被其钝化而导致放电终止。大尺寸Li2O2的生成有助于延缓正极表面的钝化、延长放电时间、提高电池容量。然而,大尺寸Li2O2在电极表面往往随机散落,难以保证其与电极材料之间的有效接触,从而限制了电池的倍率性能和能量效率。因此,亟需实现大尺寸Li2O2在电极材料中的嵌入式生长。
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发布时间：2023-12-18 - 摘要：<正>以"创新创业创造,迎接智能社会"为主题的2017世界机器人大会8月23日在北京亦创国际会展中心开幕。出席开幕式的工信部副部长辛国斌表示,中国机器人产业近年发展迅猛,但与成熟产业相比仍处于起步阶段。技术产品不够丰富、产业规模总体偏小,应用领域还很有限,尚不能有效满足先进制造业和人们生活的需求。正因如此,我国机器人产业的市场空间广阔、发展潜力巨大。
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发布时间：2023-12-18 - 摘要：<正>近日,行业技术领先的压铸铜转子生产商——云南铜业压铸科技有限公司（"云铜压铸公司"）新压铸生产线——3号线试生产成功。据了解,云铜压铸3号新生产线试生产成功,比预定计划提前1个月建成。截止8月25日,云铜压铸已完成76549台铜转子的生产,提前4个月完成了今年全年生产7万台铜转子的目标。压铸公司2017年预计将生产11万台铜转子,较2016年产
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发布时间：2023-12-18 - 摘要：<正>8月16日上午,新松机器人（苏州）未来科技城项目签约落户苏州相城区。仪式上,新松机器人投资有限公司与苏州高铁新城签约,共同成立苏州新松机器人产业发展有限公司,并共同发起成立产业基金,积极推进国家级协同创新中心建设。据悉,项目将打造"五位一体"的机器人特色科技城,实现机器人有关的产业达成集聚发展效应。
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发布时间：2023-12-18 - 摘要：The effects of infiltrating silica sol process on mould surface roughness of SLS coated sand were investigated by infiltrating silica sol and post-processing into green part of SLS coated sand.The results reveal that,with the increase of the temperature and time of the silica sol infiltration,the surface roughness of the SLS coated sand mold is reduced firstly and then increased.With the silica sol infiltration at30 ℃for 15 h,the surface roughness of coated sand casting reaches the maximum value（Ra）of 11.48μm.With the increase of curing temperature and time of coated sand,surface roughness of SLS coated sand mould are decreased firstly and then increased.With the coated sand after curing temperature at 30℃for 15 h,the minimum surface roughness of coated sand casting reaches（Ra）13.96μm.关键词：SLS Coated Sand;Silica Sol;Roughness
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发布时间：2023-12-18 - 摘要：In the post-procedure of stainless steel investment casting,a large amount of waste powder can be formed,which contains plenty of stainless steel powder and scraps.Through adopting electrostatic separation technique and correspondingly selecting reasonable process parameters,based on the different electrical properties of different components in the powder,the effective selection of these powder waste can be realized as a result of certain components moving with different tracks under high-voltage corona field and high-voltage electrostatic field,and the high quality recycled stainless steel powder can be produced,which has been proved to be an economic and environmentally-friendly separation for stainless steel powder.关键词：Investment Casting;Stainless Steel Powder;Electrostatic Separation
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发布时间：2023-12-18 - 摘要：Based on researching aluminum melting technology and casting rolling process as well as controlling the key parameters of production process and analyzing the microstructure,aluminum rod with excellent properties were produced.The results show that the ultra-fine drawn aluminum rod can be produced by controlling hydrogen content in liquid aluminum alloy below 0.15mL/100 g,setting rational cooling water as well as controlling grain degree of the billet to grade 1.Through the control of the key parameters of the rolling process,such as temperature of the rolling process and concentration of the emulsion,the produced aluminum rod can been drawn to 0.12 mm,and the wire breaking rate of the drawing process is reduced to 110min/times.关键词：Continuous Casting and Rolling;Aluminum Alloy Rod;Hydrogen Content
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发布时间：2023-12-18 - 摘要：Effects of reheating temperature on microstructure and tensile properties of the Ti@Al3Ti/2024 Al matrix composites fabricated by powder thixoforming were investigated.The results indicate that the primaryα-Al particles are coarsened gradually and the reaction shell of Al3Ti is increased with increasing the reheating temperature.The crack mode of the composites is transformed from defect fracture into the ductile fracture and finally into brittle fracture.The results indicate that the composites thixoformed at 645 ℃ have the desirable comprehensive tensile properties,where the ultimate tensile strength and elongation reach 361 MPa and 13.7%,respectively.关键词：Powder Thixoforming;Ti@Al3Tip/2024Al Matrix Composites;Reheating Temperature
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发布时间：2023-12-18 - 摘要：The effects of P on the microstructure and mechanical properties of 20Mg2Si/Al-Si composites fabricated by in situ reaction were investigated.The results show that the primary Mg2Si phase in the composites without P addition presents the feature of coars dendrite or polygonal block,while the primary Mg2Si phase is changed from dendrites to fine particles with the addition of P element,which is attributed to the elements Al and P forming a compound of AlP to be acted as heterogeneous nucleation sites.The hardness and tensile strength of the composites without P addition are 71.5 HB and 102.1MPa,respectively,while with adding P element,the hardness and tensile strength of the composites are increased to 97.2HB and 133.6 MPa,respectively.关键词：Primary Mg2Si;Al Matrix Composite;P Modified;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：3% short carbon fiber with a length of 3mm reinforced 2024 Al matrix composites were fabricated by vacuum hot press sintering（VHPS）.The effects of VHPS parameters on density,grain size,interface structure and hardness of the composites were investigated.The results reveal that the optimized VHPS processing parameters are sintered at 450 ℃ for 50 min and 50 MPa,where the specimens sintered exhibit compact structure with the desirable interface bonding between Cfandα-Al matrix,and the maximum hardness can be obtained.The improvement of mechanical properties by addition of 3% Cucoated Cfare more obvious than that of the non-coating Cfwith Cu coating on carbon fiber as a result of Cu-coating improving wettability of fiber withα-Al matrix.关键词：Cf/2024 Composites;Vacuum Hot Press Sintering;Interfaces;Hardness
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发布时间：2023-12-18 - 摘要：The effects of copper on the microstructure and mechanical properties of ZL114 Aaluminum alloy were investigated by optical microscope,scanning electron microscope and tensile testing experiment.The results reveal that there exist changes-absent in the microstructure or the mechanical properties with copper content less than 0.1%,which indicates that the copper is completely soluted in the matrix.As the increasing in Cu content,the tensile strength of the alloy is increased fast firstly and then declined slightly while the elongation is decreased.With the Cu content of 0.5%,the tensile strength and elongation of the alloy reach 337.21 MPa and 3.4%,respectively.Furthermore,the EDS data verifies that the improvement mechanisms of alloy is attributed to dispersed precipitation of the second phase W（Al2Mg5Si4Cu4）to form second phase strengthening effects with the content of Cu exceeding 0.1%（the limit of the matrix solid solubility）,and there exists also lattice distortion being generated as the second phase to improve the tensile strength of the ZL114 Aaluminum alloy.关键词：ZL114A alloy;Copper;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of Ca content on porosity,microstructure,phase composition,compressive strength,micro-hardness and corrosion resistance of porous Mg-1Zn-xCa alloys were investigated.The results reveal that with the increase of Ca contents,the porosities of porous Mg-1Zn-xCa alloys are decreased.However,the compressive strength and micro-hardness of the alloy are increased firstly and then decreased slightly.The compressive strength and micro-hardness of porous Mg-1Zn-2Ca reach 35.6MPa and 51.2HV,respectively,which are 46.5% and 35.4% higher than those of porous Mg-1Zn alloy.SEM analysis shows that the compactness of the pore cell（porous material matrix）of porous Mg-1Zn-xCa alloy is increased with the increase of Ca contents.XRD and EDS analysis show that the porous Mg-1Zn-2Ca alloy is composed of single phase ofα-Mg solid solution,and porous Mg-1Zn-2.5Ca alloy consists of two phases ofα-Mg and Mg2 Ca.Corrosion resistance measurement reveals that the corrosion rates of porous Mg-1Zn-xCa alloys are decreased firstly and then increased slightly by increasing in Ca content.The porous Mg-1Zn-2Ca alloy has the minimum corrosion rate of 0.15mm·a-1 and desirable corrosion resistance with immersed in SBF for 48 h.关键词：Porous Mg-Zn-Ca Alloy;Ca Content;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：The electric spark deposition method was used to strengthen TC4 alloy surfaces under powdermixed near-dry EDM.Through the medium mixed with B4 C powder,graphite electrode as the tool electrode,the hardness of titanium alloy surface was improved by forming strengthening layer with enriched in C,B,Ti and Al phases.The results indicate that dense,well combined with matrix and cascade chrysanthemum petal-like microstructure can be observed,and with increasing in current,the grain size is increased.It is found that the micro-hardness of about 899 HV and 1 039 HV can be obtained when the current is 3.7Aand 6.6A,which is improved significantly compared with that of the original alloy（about 312HV）.XRD results reveal that TiC,TiB,B8C,Al3BC,Al3Ti and Al5Ti2 phases can be observed in the strengthening layer.The metastable phase of Al3.3Ti appears,and the phase of Ti-Al intermetallic compound is increased significantly with the current of 6.6A.关键词：Powder-Mixed Near-Dry EDM;TC4Alloy;Microstructure;Microhardness;Phase Composition
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发布时间：2023-12-18 - 摘要：In order to realize the recycling use of the scrap wires of AZ31 Mg alloy,the wires were joined using TIG spot welding.The microstructure and mechanical properties of welded joints of magnesium alloy wires were analyzed by scanning electron microscope,metallurgical microscope and universal testing machine.The results reveal that TIG spot welding technology can realize a reliable joint of the scrap magnesium alloy wires.The tensile strength of the joints can reach 80% of the substrate material.In addition,the joint has good bending resistance.关键词：Mg Alloy;Wire;Recycling Use
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发布时间：2023-12-18 - 摘要：Five kinds of A356 alloys were prepared by compound refining modification,micro-alloying and T6 heat treatment.The mechanical properties,microstructure and thermal fatigue properties of A356 alloys under different temperatures were investigated,and the growth behavior and mechanism of fatigue crack were analyzed.The results reveal that,the mechanical properties of as-cast A356 alloys can be improved by compound refining modification,micro-alloying and T6 heat treatment.After T6 heat treatment,the morphology of the eutectic silicon phase is changed from needle plate to granular and the degree of roundness of eutectic silicon was improved in A356 alloy with complex refinement and composite refinement & micro-alloying.The thermal fatigue crack initiation life of as cast A356 alloy can be improved by composite refinement modification,micro-alloying and T6 heat treatment.The thermal fatigue life of the alloy is decreased with the increase of the temperature amplitude limit when the temperature amplitude limit is constant.The crack initiation and propagation rate of the alloy E after composite refinement modification + micro-alloying+ T6 heat treatment is the lowest and the thermal fatigue life is the longest.关键词：A356 Alloy;Composite Modification;Micro-Alloying;T6Heat Treatment;Thermal Fatigue
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发布时间：2023-12-18 - 摘要：The effects of La and Pr composite modification on the mechanical properties and microstructure of Al-Cu alloy were investigated by OM,TEM and tensile testing,and the existing forms and mechanism of La and Pr were described.The results reveal that the peak hardness of 0.3%（La+Pr）composite modified Al-Cu alloy at different aging temperature is the higher than that of unmodified AlCu alloy,and the suitable aging treatment process is at 165℃for 10 h.The tensile strength and elongation at room temperature of La+Pr composite modified Al-Cu alloy are significantly higher than those of unmodified Al-Cu alloy,and the tensile strength and elongation reach the maximum value with 0.2%La+0.1%Pr composite modification on Al-Cu alloy,In addition,the tensile strength and elongation at high temperature are the higher than that of unmodified Al-Cu alloy at the same temperature.The main strengthening mechanism of 0.2%La+0.1%Pr composite modified Al-Cu alloy belongs to fine grain strengthening and second phase strengthening.关键词：La;Pr;Al-Cu Alloy;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：The effects of Yb and Er addition on the mechanical properties,electrical conductivity and high temperature creep properties of 8030 conductive alloys were investigated by tensile testing.The content of Fe,Cu,Yb and Er was optimized.It is found that ambient-temperature mechanical properties are improved,while electrical conductivity is decreased with increasing in alloying elements.However,the excessive amount of Fe and Cu is deteriorated to the high temperature creep resistance performance,while the Yb and Er addition can improve the high temperature creep resistance of the alloy.After hot extrusion+hot rolling+cold rolling+ageing at 180℃for 1h,the tensile strength（159177MPa）at ambient temperature and electrical conductivity at 20 ℃（34.8635.84 MS/m）of all alloys can meet the requirements of the AT1 alloy standard specified in the IEC62004.The experimental results show that the Al-0.55Fe-0.15Cu-0.05Yb-0.10 Er alloy has the optimum ambient-temperature mechanical properties,high temperature creep resistance and electrical conductivity.关键词：8030 Alloy;Mechanical Properties;Electrical Conductivity;Creep
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发布时间：2023-12-18 - 摘要：Effects of Sr element on the microstructure and mechanical properties of Mg93Zn6 Y alloy were investigated.The results show that with the increase of Sr addition,the grain size of primaryα-Mg phase in the alloy is decreased gradually from 1 190μm to 360μm.Meanwhile,secondary phase is refined gradually with the improvement of partial segregation.With increasing in Sr addition,the tensile strength and elongation of Mg93Zn6 Y alloy are increased.With 0.4% Sr addition,the tensile strength and elongation of the alloy reach up to 191 MPa and 3.8%,increased by 43.6%and 90.0%,respectively,compared with those of the unrefined alloy.关键词：Sr Element;Mg93Zn6Y Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The hypereutectic Al-20 Si alloys were modified by P and rare earth element La,and effects of P and La on the modification of primary silicon phase in the alloys were investigated.The experimental results indicate that the addition of P can refine greatly primary silicon phase in hypereutectic Al-20 Si alloy.The primary silicon phase in modified alloys is changed into fine granule from coarse block shape in unmodified alloys and well-distributed in matrix.The optimal refinement on the primary silicon phase can be obtained when the content of P is 0.06%,where the average size of primary silicon phase is decreased from 122μm to 25μm.However,with the addition of 0.09% P,the primary silicon in the alloy can be coarsened.The complex modification of P-La can further improve the refining effect of primary silicon.The optimal refinement on eutectic silicon in the alloy can be observed when the content of La is0.9%,while with La of 1.2%,over-modification effects can be observed.关键词：Hypereutectic Al-20Si Alloy;P-La Complex Modification;Primary Silicon
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发布时间：2023-12-18 - 摘要：Nb-22.5Cr alloy adding with 0.125% Nd2O3 was prepared by mechanical alloying and hot pressing.The effects of Nd2O3 on thermal stability of Nb-22.5Cr alloy were analyzed through thermal exposure experiment at 1 200 ℃.The results reveal that the Nb-22.5Cr alloy can still remain high relative density and good fracture toughness after thermal exposure for 100 hby adding with Nd2O3.Meanwhile,the variation rate of properties,such as hardness and room temperature compressive mechanical properties,is decreased gradually.The results indicate that the thermal stability of Nb-22.5Cr alloy can be improved by adding Nd2O3 particles.关键词：Nb-Cr Alloy;Nd2O3;Thermal Stability
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发布时间：2023-12-18
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