最新刊期
卷 37 ， 期 10 ， 2017
- 摘要：The microstructure,mechanical properties and fracture behaviors of Mg-6Zn-1.5Cu alloy at ascast,solution and aging treatment were investigated by OM,SEM,TEM,XRD and mechanical tests,respectively.The experimental results indicate that the microstructure of the as-cast alloy is composed ofα-Mg,semi-continuously or continuously distributed intermetallics（α-Mg+MgZn2+Mg2Cu+CuZnMg）at grain boundaries and isolated particles in the grain.With the increase of holding time,solution effects and aging strengthening effects of the alloy are increased gradually with solution treatment at 450℃ for 12,20,28 and 36 h,and then aged at 180℃ for 12,20,28 and 36 h.With the solution and aging time more than 28 h,residual eutectic compounds and aging strengthening precipitation present coarsening phenomenon.With aged at 180℃ for 28 h,the alloy with desirable structure presents tensile strength and elongation of 265 MPa and 15.90%,respectively.The fracture morphology of the as-cast alloy is characterized by cleavage and inter-granular fracture,while the fracture behavior of the alloy aged is dominated by the mixture of inter-granular and trans-granular modes.关键词：Mg-6Zn-1.5Cu Magnesium Alloy;Microstructure;Heat Treatment;Mechanical Properties;Fracture Behavior
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发布时间：2023-12-18 - 摘要：Five typical metal materials for fashion jewelry,including 316L stainless steel,TA2 pure titanium,CoCrMo alloy,tungsten carbide and TaC system carbide,were investigated comparatively from physical properties,chemical properties,mechanical properties,process performance and safety performance.The results show that all the experimental materials belong to colorless with the highest brightness for CoCrMo alloy and the highest chromatic value for TaC system carbide.The five materials have excellent corrosion resistance in the artificial sweat,especially the highest corrosion potential for TA2 while the lowest for tungsten carbide.The higher hardness of the material presents the lower wear weightlessness rate in the wet erosion test,accordingly the glossiness on jewelry surface can be kept the longer.316 L,TA2 and CoCrMo alloy can adopt a variety of forming processes,in which 316L and TA2 alloy are more suitable for setting ornamental stones directly,and they can be colored by anodic oxidation process,by contrast,tungsten carbide and TaC system carbide can only be formed by powder metallurgy and linear cutting,which are unsuitable for setting stones directly.TA2 and CoCrMo alloys have the desirable biocompatibility among them.关键词：Fashion Jewelry;316LStainless Steel;TA2 Pure Titanium;CoCrMo Alloy;Tungsten Carbide;TaC System Carbide
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发布时间：2023-12-18 - 摘要：The relationship between pressing pressures and pressed densities of W powders with average size of 46μm was investigated systemically by combining theoretical calculation with experimental analysis,and the equation was deducted based on Huang’s formation theory.According to the equation,the molding parameters were selected to prepare the W-15 Cu composites with W-skeleton sintered at high temperature and infiltration method.Microstructure of W-skeleton and the composites prepared was observed by SEM,and density,hardness and electric conductivity were measured.It can be found that after pressing,W powders with average size of 46μm can follow the Huang’s formation theory.The Cu content in CuW composites prepared by isostatic cool pressing at 250 MPa and 1 850℃ reaches 15%,where electric conductivity,hardness（HB）and thermal conductivity reach 21.98 MS/m,221 and196 W·m-1·K（-1）,respectively.关键词：Isostatic Cool Pressing;Pressing Pressure;Density;Infiltration
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发布时间：2023-12-18 - 摘要：<正>近日,包头稀土研究院中试基地稀土镁合金中试线完成镁合金半连续熔铸系统的调试生产,制备出?300mm×4 000mm的镁合金棒材。对其进行超声无损检测发现,合金铸棒无铸造缺陷,符合对应产品质量要求,下一步将进行大尺寸稀土镁合金棒材的产业化制备工艺开发。镁合金半连续铸造技术是将金属液体经过结晶器凝结成壳后从下方拉出喷水冷却成具有一定断面形状和一定长度的铸坯的过程。半连续铸造生产的锭坯具有晶粒细小、
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发布时间：2023-12-18 - 摘要：<正>铝基非晶合金以其高的比强度和优异的耐腐蚀性能而备受关注,在航空、航天等领域中轻质构件材料应用极具发展前景。然而,铝基非晶合金体系低的玻璃形成能力是制约其工程化应用的瓶颈。金属所沈阳材料科学国家（联合）实验室非平衡金属材料研究部王建强研究员课题组与美国约翰霍普金斯大学马恩教授合作,在Al基金属玻璃的结构及玻璃形成能力等方面进行了多年的研究探索。在Al-TM（过渡金属）-RE（稀土）为基础的三元合金系中,分别以TM和RE作为溶质中
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发布时间：2023-12-18 - 摘要：<正>2017年9月,我国汽车产销分别完成267.1万辆和270.9万辆,产销量比上月分别增长27.6%和23.9%,比上年同期分别增长5.5%和5.7%。19月,汽车产销分别完成2 034.9万辆和2 022.5万辆,比上年同期分别增长4.8%和4.5%,低于上年同期8.5和8.7个百分点。乘用车产销呈现增长,同比增速低于汽车总体。9月,乘用车产销分别完成229.7万辆和234.3万辆,产销量比上
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发布时间：2023-12-18 - 摘要：<正>澳大利亚工业、创新与科学部数据显示:2017年前8个月,全球铝产量超4 000万吨,较去年同期同比增长5.8%。其中,今年前8个月,中国铝产量较去年同比增长7.7%,亚洲地区（除中国外）同比增长14%,南美地区同比增长3%。该部门还表示,为弥补中国冬季限产所造成的产能缺失,中国的铝生产商2017年上半年大幅提升铝产量至1 700万吨,同比增长11%。
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发布时间：2023-12-18 - 摘要：<正>近日,深圳市长盈精密技术股份有限公司（"长盈精密"）与潮州三环（集团）股份有限公司（"三环集团"）分别发布公告称,经双方协商一致,同意终止《合作成立合资公司的框架协议》、《关于合资成立潮州三环长盈新材有限公司的协议书》等双方共同签署的合资协议。此举意味着双方终止了原计划的智能终端和智能穿戴产品的陶瓷外观件及模组项目。公告称,经各方协商一致,同意注销此前合资成立的东莞长盈三环陶瓷技术有限公司和潮州三环长盈新材料有限公司。长
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发布时间：2023-12-18 - 摘要：<正>近日,江苏泰州一汽新能源客车项目正式签约泰州经济开发区。该项目由江苏正豪新能源汽车有限公司（"江苏正豪"）投资建设,总投资约30亿元,核心生产技术均来自一汽集团技术中心。主要生产新能源商用汽车和新能源专用汽车及相关零部件。据了解,一汽新能源客车项目,总投资约30亿元,用地面积约570亩,总建筑面积约16.8万平方米。建成以新能源商用汽车和新能源专用汽车及相关零部件生产基地。项
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发布时间：2023-12-18 - 摘要：<正>近日,南京埃斯顿自动化股份有限公司（下称"埃斯顿"）发布公告称,拟签署股权收购协议,出资约886.9万欧元（人民币6 895.6万元）,收购德国M.A.i.公司50.01%股权,并对剩余股份有优先收购权。据了解,M.A.i.公司成立于1999年,总部位于德国Kronach市,主要业务是为提供以机器人应用为基础的,高度自动化、信息化、智能化的装配和测试生产线,服务于汽车引擎和电子系统部件、半导体、航空部件和医疗器械等行业。
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发布时间：2023-12-18 - 摘要：<正>据SMM 2017再生铅蓄电池产业峰会上的数据,新能源汽车产业的发展已成大势所趋,2017年17月,新能源汽车产销分别完成27.2万辆和25.1万辆,同比分别增长26.2%和21.5%。其中纯电动汽车产销分别完成22.3万辆和20.4万辆,同比分别增长37.8%和33.6%;插电式混合动力汽车产销分别完成4.9万辆和4.7万辆,同比分别下降8.8%和12.8%。
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发布时间：2023-12-18 - 摘要：<正>常州世竟液态金属有限公司新工厂,在常州武进国家高新区创新园区正式投产。据悉,新工厂采用真空压铸、真空熔炼技术,开发和制造液态金属材料、压铸件产品,广泛应用于消费电子、智能装备、医疗设备等领域。常州世竟液态金属有限公司是一家专业从事液态金属材料研发、制造、销售的公司,致力于为消费电子、智能装备及先进医疗设备客户提供完整的液态金属解决方案。液态金属在消费电子领域的应用:外观结构件、结构相对较为复
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发布时间：2023-12-18 - 摘要：<正>世界金属统计局（WBMS）周三在其网站上公布的数据显示,今年前7个月全球铜市供应短缺19.7万吨,2016年全年为短缺10.1万吨。今年7月全球铜消费量为204.45万吨,17月为1 379万吨,上年同期为1 377万吨。中国前7个月消费同比减少7 600吨至673.7万吨,且占到全球需求仅位于49%下方。欧盟28国产量同比增加8%,且需求为204.9万吨,较上年同期减少0.5%。
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发布时间：2023-12-18 - 摘要：<正>由重庆大学牵头,重庆大学潘复生教授负责的国家重点研发计划"大规格高性能镁合金变形加工材制造关键技术"项目2017年度进展总结会在辽宁省沈阳市召开。据悉,镁合金作为重要的先进轻合金材料已列入国家科技创新发展规划。该研发计划项目的进行,有望在大规格高性能镁合金变形加工材制造关键技术研发上取得重要突破,将进一步强化与夯实我国变形镁合金的技术发展和产业进步基础,推动高性能镁合金在交通工具、航空航天、
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发布时间：2023-12-18 - 摘要：The filling and solidification process of gypsum mold Low-pressure casting shell were simulated by View Cast software.According to the simulated results,the size and location of possible defects in shell castings were predicted.The simulated results reveal that there exist a large area of shrinkages in the ear position of shell castings.The flake shrinkages appear in the side of the first produced castings.The position and cause of defects generated was analyzed,and the initial process was optimized by changing process parameters,such as increasing the chiller at the thick wall,adding the ingate,then the solidification simulation was carried out again.The final simulated results reveal that the optimized process scheme can reduce casting defects,presenting its feasibility.There exist no defects in the actual production,meeting the production requirements.关键词：Shell;Gypsum Mold Low Pressure Casting;Numerical Simulation;Process Optimization
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发布时间：2023-12-18 - 摘要：The sand casting process of aluminum alloy cover was simulated by AnyCasting,and origination of defects was analyzed.Aiming at the casting defects in the sand casting process,by modifying gating system,setting the cold iron and riser reasonably,and increasing the casting speed,the casting defects can be reduced greatly,and the casting quality can be improved.关键词：Sand Casting;Aluminum Alloy;Process Optimization;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The gravity casting process of A356 aluminum alloy wheel was analyzed by numerical simulation to understand origination of casting defects and effect of air plug.The results reveal that solidification sequence of casting can be changed and casting defects can be reduced through setting air plug in the rational place.The actual production verified the simulation ones.关键词：A356Alloy;Numerical Simulation;Air Plug;Solidification Defects
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发布时间：2023-12-18 - 摘要：The source and hazard of inclusions in the copper alloys were described.The current situation and research progress of filtration purification technology at home and abroad for copper alloy melt were reviewed.The ceramic foam filtering mechanism and the thermodynamic conditions of filter to adsorb spontaneously non-metallic inclusions were emphasized.At last,the development prospect of filtering purification technology of copper alloys was presented.关键词：Copper Alloys Melt;Filtering Purification;Inclusions
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发布时间：2023-12-18 - 摘要：Application of 3DP and SLS sand core（mould）3D printing technology has been researched in railway castings.Sand samples were printed by two technology,and properties were tested.Coupler knuckle cores were printed using two technology,and casting experiment has been carried out.The results show that compressive strength and gas evolution of the 3D printed sand cores can meet casting production requirements.Both two 3D printing technology can produce coupler knuckle cores efficiently without casting mould,and coupler knuckles have precise size and smooth surface.关键词：3D Printing;3DP Technology;SLS Technology;Railway Castings
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发布时间：2023-12-18 - 摘要：The structure characteristics of 3 000 kN vertical semi-solid squeeze casting machine was described.The rheological process of aluminum alloy and the structure and properties of the aluminum alloy parts formed by rheological process combined with indirect squeeze casting were investigated.The results reveal that the vertical semi-solid squeeze casting machine is composed of bottom feeding,indirect squeeze casting and two-pressurization in the inner cavity.Entrapped-gas can be avoided by squeeze casting at the bottom.By the two-pressurization in the inner cavity of die,the solidified metal can be compensated effectively,and the microstructure and properties of the workpiece can be improved remarkably.关键词：Semi-solid;Rheological;Squeeze Casting Machine;Two-pressurization
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发布时间：2023-12-18 - 摘要：The technology of die casting aluminum cooling module was analyzed and compared based on numerical simulation.The optimized HPDC process was determined based on the better quality of important zone as project.After the trail production,the high-quality die castings can be produced sucessfully.The result shows that the numerical simulation method can reduce the time of trial-production,shortening the development period.关键词：Aluminum Alloy;Die Casting;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Microstructure and mechanical properties of Al-12Si alloy under pressurized solidification were investigated by OM,SEM and hardness testing.The results reveal that microstructure of the alloy is changed with pressurized solidification.And the tensile strength,elongation and hardness of the alloy are improved remarkably.When the specific pressure is increased from 0 MPa to 650 MPa,the size of primaryα-Al and aspect ratio of eutectic Si phase is decreased obviously.Meanwhile,the morphology of eutectic Si particles is changed from long needle-like to small vermicular and granular structure,and the fracture morphology is changed from brittle fracture to ductile one.关键词：Al-12Si Alloy;Specific Pressure;Structure Refinement;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of ultrasonic power and solidification pressure on the hardness of ZL114A aluminum alloy were investigated.Meanwhile,the relationship between hardness and ultrasonic power as well as solidification pressure was established.The results show that the ultrasonic power and solidification pressure has a significant effect on the Vickers hardness of the ZL114A alloy.At the fixed solidification pressure,with the increase of ultrasonic power,the Vickers hardness of the sample is increased firstly and then decreased,and when the ultrasonic power is 600 W,the Vickers hardness of the sample reaches the maximum value.At the same ultrasonic power,the Vickers hardness of the sample is increased with the increase of the solidification pressure.When the ultrasonic power is 600 Wand the solidification pressure is 350 kPa,the Vickers hardness of the sample reaches the maximum value.关键词：ZL114A Aluminum Alloy;Vickers Hardness;Ultrasonic Power;Solidification Pressure
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发布时间：2023-12-18 - 摘要：With the help of Magma software,the high pressure die casting process of automobile engine bracket was simulated.The results show that the bracket’s defects type and location predicted are well agreement with practical ones.The uneven part surface and thickness and gate solidification ahead result in difficulties in exhausting air,together with the poor effect of pressure at the distal end,which are responsible for generation of gas hole.Through analysis of gas hole formation and location,local squeezing device was designed to solve gas holes around the distal bearing hole,and it was observed by X-ray imaging system.Thus,the efficient engine bracket production mode combining with local squeezing process and high pressure die casting as well as CAE analysis was established,which could reduce gas hole rate in the engine bracket to 0.6%,improving effectively production efficiency.关键词：Automobile Engine Bracket;Local Squeeze;Die Casting;Porosity;Numerical Simulation
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发布时间：2023-12-18 - 摘要：In order to improve the expanding performance of the clamping unit in vertical squeeze casting machine,the working principle and structure feature of double toggle clamping unit were analyzed,and the virtual prototype parametric model of the half clamping unit was established based on design points by using ADAMS software.The expanding force coefficient Mp（α=3°）was regarded as objective function for the optimization,and the optimum design variables were determined by analysis.At meeting the design constraints for vertical double-toggle clamping unit,the clamping unit was optimized by using Successive Quadratic Programming（SQP）.The optimized results show that the expanding force coefficient is increased by 5.02%,and the maximum clamping force is increased by 6.14%,realizing the goal of optimization and meeting the design requirements.关键词：Vertical Squeeze Casting Machine;Clamping Unit;Parametric Model;Optimization Design
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发布时间：2023-12-18 - 摘要：The accuracy core-assembly molding process for complex projectile aluminum alloy casting was described including the casting process design,process modeling analysis,mold design,core making and core assembly method.Finally,complex projectile aluminum castings with high dimensional accuracy and high quality were produced.The molding process can be applied for different aluminum casting products.关键词：Complex Aluminum Alloy;Mold Design;Accuracy Core Assembly;Molding Process
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发布时间：2023-12-18 - 摘要：The fluidity of Ti-6Al-4V alloy remelting in vacuum induction arc furnace was measured in graphite mold and ceramic mold by adopting spiral-type fluidity testing sample.The fluidity of Ti-6Al-4V alloy in the two casting mold and Ti-6Al-4V containing different Fe in ceramic mold were analyzed comparatively.The results show that the mold material has great influence on the fluidity of Ti-6Al-4V,where the length of spiral-type sample in ceramic shell is as nearly two times as in graphite mold.In addition,fluidity of Ti-6Al-4V in ceramic shell is declined slightly with the increase of Fe content,where the length of spiral-type sample with 0.25% Fe reaches 80% of ones with 0.05%Fe.关键词：Fluidity;Casting Ti Alloy;Spiral-type Samples
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发布时间：2023-12-18 - 摘要：The origination of forming bulge defect in the investment casting check valve baffle was analyzed.The main cause of the defect is attributed to the bulge of large plane shell during molding and pouring process.Through inserting stainless steel wire in the wax pattern plane to form technological concave,and adopting special clamping fixture during pouring process,the bulge defects can be eliminated effectively.关键词：Investment Casting;Bulge;Technological Concave;Clamping Fixture
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发布时间：2023-12-18 - 摘要：Microstructure and precipitated phase morphology of ZL205A alloy were investigated by centrifugal machine at 1 g、1 000 g、2 000 g、3 000 g、4 000 g(1 g=9.8 m·s-2),and effects of high gravity field on the properties of ZL205A alloy were analyzed.The results reveal that,the high gravity field can reduce segregation defects in ZL205A alloy and refine obviously grain size.In the normal gravitational field of 1 g,the solidification structure in ZL205A alloy presents the large blocky segregation,and the grain size reaches 85μm.However,the segregation in the high gravity field is decreased with increasing in the high gravity field.When the gravity field reaches 4 000 g,the segregation reaches the lowest,and the grains become equiaxed grain with size of 35μm.The high gravity field can improve the morphology of precipitated phaseθ-phase.When the gravity field is 1 g,theθ-phase presents coarse bulky structure,while in the high gravity field,the θ-phase becomes small blocky structure.The refinement effects is increased with increasing in the gravity field.The hardness of ZL205A can be increased under high gravity field,which is 64.3 HV under normal gravity field,while it is 83.4 HV at 3 000 g.关键词：High Gravity Field;ZL205A Alloy;Segregation;Grain Refinement;Hardness
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发布时间：2023-12-18 - 摘要：The effects of complex modification of Sb+Ce on the primary Mg2Si phase in 20%Mg2Si/Al-5Si composites fabricated by in situ reaction were investigated.The results reveal that the average size of the primary Mg2Si particles is decreased firstly and then increased with the 0.2%Sb+xCe modification.The primary Mg2Si particles reach 28μm with uniform distribution with the addition of 0.2%Sb+0.6%Ce.With the addition of 0.4%Sb+xCe,the primary Mg2Si particles can be modified effectively and its average size reaches 3040μm.The optimum modification effect can be observed with the addition of 0.6%Sb+xCe,where average size of primary Mg2Si particles reaches 2731μm with the higher roundness and more uniform distribution.关键词：Complex Modification;Primary Mg2Si;Al Matrix Composite;Modification Mechanism
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发布时间：2023-12-18 - 摘要：Effects of reheating duration on the microstructure and tensile properties of Ti@（Al-Si-Ti）p/A356 composites fabricated by powder thixoforming were investigated.The results indicate that the primaryα-Al particles in the thixoformed Al based composites are coarsened obviously and the shape becomes more and more irregular with increasing in the reheating duration.Simultaneously,an expected core-shell structured Ti@（Al-Si-Ti）particle with a thick and compact shell is formed gradually around each Ti core.Then the shells are cracked and peeled off from the Ti cores with the transformation from τ1 phase into（Al,Si）3Ti phase after 50 min.The results from the tensile testing indicate that the mechanical properties of the composites are increased firstly and then decreased.The tensile strength,yield strength and elongation of the composites reach 373 MPa,268 MPa and 8.3%,respectively,with reheating duration time of 50 min.关键词：Powder Thixoforming;Al Matrix Composites;Core-Shell Structured Particle
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发布时间：2023-12-18 - 摘要：Carbon fibers with nickel coating reinforced aluminum matrix composites were prepared by stirring method,and it was analyzed by scanning electron microscope,XRD and universal tensile testing machine.The results reveal that carbon fibers are dispersed well in the matrix of aluminum by stirring.The Ni coating is dissoluted in the matrix to form Al3Ni phase as a result of the reaction between the aluminum matrix and the nickel coating.The Al3Ni can prevent effectively the brittle phase Al4C3 formed between the carbon fibers and the matrix.The tensile strength of the composites is increased with the increase of carbon fiber content.Compared with those of the pure aluminum,when the content of carbon fibers is 5% and 7%,the tensile strength of the composites prepared is increased by 29% and 35%,respectively,while the plasticity is decreased obviously.关键词：Carbon Fibers;Nickel Coating;Composites;Mechanical Stirring;Tensile Strength
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发布时间：2023-12-18 - 摘要：A C/C composites for piston with obvious anisotropy was prepared.The microstructure of the composites was characterized by metallographic microscope and scanning electron microscope.The tensile strength,thermal expansion coefficient and friction-wear properties of the composites were investigated.The results show that as the piston C/C composites,chemical vaporization infiltration（CVI）is used to prepare the deposited carbon with rough laminar structure to improve its thermal conductivity and avoid the smooth structure of sedimentary carbon.At room temperature,the tensile strength of the composites at the X and Z directions exhibits desirable,about 400 MPa.The thermal expansion coefficient at the X and Z directions is less than 0.5×10-6 K-1,while the thermal expansion coefficient at Y direction is closed to zero.Long fiber coiled C/C material has the higher wear resistance than high nickel cast iron.关键词：C/C Composites;Mechanical Properties;Piston
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发布时间：2023-12-18 - 摘要：<正>2017年9月2326日,由中国材料研究学会（CMRS）主办,中国科学院金属研究所承办的第六届国际镁及镁合金会议在沈阳召开。来自中国、德国、英国、加拿大、日本、韩国、澳大利亚等11个国家的400余名代表参加了本次会议。镁合金由于其低密度、比强度高等极具吸引力的特征,使其在汽车、航空航天、计算机、通讯和消费品工业的应用潜力与日俱增。尽管2008年的全球经济危机和镁价格动
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发布时间：2023-12-18 - 摘要：Through Zr55Cu30Al10Ni5 amorphous alloy inoculant as modifier of ZL205 alloy,the high temperature mechanical properties of ZL205 alloy at different temperatures and strain rates were analyzed,and effects of modification on the deformation mechanism of ZL205 alloy at high temperature were described.The results reveal that,the engineering stress and fracture strain of the unmodified ZL205 alloy are lower than those of the modified ZL205 alloy.With the increase of the deformation temperature,the stress sensitivity of the ZL205 alloy un-modified and modified is improved gradually,and the stress sensitivity of the modified ZL205 alloy is the higher than that of the unmodified ZL205 alloy.In addition,the high temperature deformation mechanism of the alloy un-modified and modified is characterized by dislocation climbing mechanism.The number of nano precipitated phases in modified ZL205 alloy at different temperature and strain rate is increased with the smaller and more uniform distribution.And at the same deformation temperature,the thermal deformation activation energy of the modified ZL205 alloy is the higher than that of the unmodified ZL205 alloy,so that the modified ZL205 alloy exhibits the better high-temperature strength and plasticity.关键词：Modification;ZL205 Alloy;Deformation Temperature;Strain Rate;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of different pulsed voltage and pulsed frequency on distribution and morphology of primary silicon in Al-20Si alloy were investigated.The results show that primary silicon mainly presents segregation and coarsening under pulsed magnetic field,which provides possibility for the preparation of gradient materials.When the pulse voltage is 80 V,the primary silicon is coarsened with segregation,which is concentrated in the edge not in the core position.With the pulsed voltage of 160 V,primary silicon tends to be coarsened and agglomeration,however the whole distribution tends to be uniform.When the pulse voltage is 240 V,the agglomeration and coarseness of primary silicon is weakened with more uniform distribution.When the pulsed frequency is 15 Hz,the distribution and morphology of primary silicon will be independent on the increase of the pulse frequency.However,when the pulse frequency is increased to 10 Hz,the primary silicon presents segregation and coarsening effects.关键词：Pulsed Magnetic Field;Al-20Si Alloy;Primary Silicon
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发布时间：2023-12-18 - 摘要：The isothermal constant strain rate compression experiment was carried out on titanium alloy TC4 ELI at the two phase region temperature of 750950 ℃ and the strain rate range of 0.00170 s-1 by using Gleeble-3500 thermal simulation machine.The hot deformation behavior of the alloy was analyzed,and the constitutive model of the alloy was established by the Arrhenius equation and BP artificial neural network model.The results reveal that the effect of strain rate and deformation temperature on the flow stress of titanium alloy TC4 ELI exhibits remarkable,and the flow stress is decreased with increasing in deformation temperature and decreasing in strain rate.In the deformation of the two-phase region,theαphase in the original microstructure has a certain degree of spheroidization/dynamic recrystallization,and the low strain rate can promote occurrence of the spheroidization/dynamic recrystallization.The average errors reach 17.51% and 1.36% for establishment of Arrhenius equation and BP artificial neural network model for the constitutive equations,and BP artificial neural network model has a higher precision,which is more suitable for predicting the flow stress of titanium alloy TC4 ELI.关键词：TC4 ELI Titanium Alloy;Hot Deformation Behavior;Constitutive Relationship
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发布时间：2023-12-18 - 摘要：The effects of Sb additions on the microstructure and tensile properties of A356 alloy were investigated systematically,and thermal analysis and quenching experiments were carried out to explore the modification mechanism of Sb on Al-Si alloys.Microstructure observations show that with 0.4% Sb addition,coarse plate-like eutectic silicon phase can be converted into fibrous structure.Tensile tests show that the mechanical properties（especially the elongation）of A356 alloys are improved greatly.The maximum elongation value reaches 11.3% under as-cast condition,which is 79% higher than that of the unmodified alloy.Thermal analysis and quenching structure observation reveal that the nucleation temperature of eutectic Si phase is continuously decreased with Sb additions,therefore the nucleation undercooling can be increased to decrease nucleation rate of eutectic Si phase.关键词：Sb Modification;A356 Alloy;Mechanical Properties;Modification Mechanism
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发布时间：2023-12-18 - 摘要：Aimed at solving the air leakage problem（under the pressure of the 0.2 MPa）in the aluminum alloy shell castings,based on analysis of the structure and process of the castings,resin sand casting technique was adopted.In addition,with the help of the Anycasting software,the casting process was optimized.After improvement of the casting technique,the gualified rate of the air tightness of the aluminum alloy shell castings was improved from 14.3% to 71%.关键词：Aluminum Alloy;Thin-walled Shell Castings;Leakage;Process Improvement
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发布时间：2023-12-18 - 摘要：The orientation evolution of Mg alloy grains was in-situ tracked during compression at 100℃ by the electron backscatter diffraction（EBSD）method,meanwhile,quantitative analysis was also conducted on activations of slips and twinning.Effects of extension twin activation on slips activations were analyzed during deformation based on calculation of variations of Schmid factor（SF）for different slips before and after twinning.The results reveal that there are absence of distinct changes for Schmid factor of basal slips before and after twinning for Mg alloy grains with basal textured orientation,while the Schmid factor of prismatic slips is decreased distinctly after twinning and it is difficult to be activated during the subsequent deformation.In addition,the Schmid factor of pyramidal slips is increased distinctly after twinning,and it is relatively easy to be activated during the subsequent deformation.关键词：Schmid Factor;Extension Twin;Grain Orientation;Slips
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发布时间：2023-12-18 - 摘要：Effects of ultrasonic treatment on the solidification and mechanical properties of AS31 magnesium alloy were investigated,and its mechanism was described.The results reveal that with the increase of ultrasonic power,the grain size of AS31 magnesium alloy is refined obviously,and the morphology,size and distribution of eutectic Mg2Si in the microstructure of the alloy are improved greatly.With the ultrasonic power of 750 W,the eutectic Mg2Si phase in the alloy is changed from coarse Chinese script to short rod ones.The average size is reduced from 160μm to 50μm.Meanwhile,the strength and elongation of the alloy reach up to 203 MPa and 3.4%,compared with those of the non-ultrasonic treatment alloy,increased by 25% and 100%,respectively.The fracture analysis of AS31 magnesium alloy without ultrasonic treatment presents cleavage fracture,while the ultrasonic treatment AS31 magnesium alloy presents dimple fracture.关键词：AS31 Magnesium Alloy;Ultrasonic Treatment;Eutectic Mg2Si;Mechanical Properties
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发布时间：2023-12-18 - 摘要：<正>据日本媒体报道,斯巴鲁在2017年10月发表声明称,神户制钢所篡改了强度等性能数据的铝制品用于汽车和飞机。马自达也透露其乘用车使用了神户制钢生产的铝制品。两家公司都表示正在确认对安全性的影响,斯巴鲁说明"将最优先保障正在使用该制品的客户的安全"。关于无法达到与客户所承诺的性能的铝制品和铜制品,神户制钢改写了检查证明书的数据,伪造成符合标准。
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发布时间：2023-12-18 - 摘要：The charging mode and technology application of mobile phone fast charging were described,and development of lead frame material was reviewed.The tensile strength,thermal conductivity,electrical conductivity and thermal expansion coefficient of lead frame materials for mobile phone fast charging connector were analyzed comparatively.The progress of Cu-Ni-Si series alloy was introduced.The possible failure modes and origination were discussed according to the design of the main mobile phone fast charging connector,and the countermeasures were proposed to improve the quality of Cu-Ni-Si lead frame for mobile phone.关键词：Mobile Phone Fast Charging;Connectorlead Frame;Cu-Ni-Si Alloy;Failure Modes
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发布时间：2023-12-18 - 摘要：Low Ag solder Sn-0.3 Ag-0.7 Cu-0.5 Bi-Ni（SACBN）and Sn-3.0 Ag-0.5 Cu（SAC305）were selected to be analyzed comparatively.The solder reflow oven was applied to prepare the SACBN and SAC305 solder joints.The wetting angle and expansion rate of the SACBN and SAC305 solder joints were measured.The temperature of reflow soldering of SACBN is 260 ℃ and SAC305 is 250 ℃.The solder joints were treated by aging treatment at 150 ℃ for 48,72,144,192,and 240 h,respectively.The results show that the expansion rate of SACBN is 74.15% with the wetting angle of 25.87°.The expansion rate of SAC305 is 76.75% with the wetting angle of 22.11°.The wetting properties of SACBN are closed to those of SAC305.The IMC thickness of SACBN is less than that of SAC305,and the growth coefficient of SACBN is less than that of SAC305.关键词：SnAgCuBiNi Solder Alloys;Aging;Expansion Rate and Wetting Angle;Growth Coefficient
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发布时间：2023-12-18
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