最新刊期
卷 40 ， 期 3 ， 2020
- 摘要：The high-temperature flow behavior of 2024 Aaluminum alloy was investigated by isothermal hot rolling tests with a Gleeble-3500 thermal simulator.The true stress-strain curves of 2024 Awere obtained by isothermal hot compression tests at the temperature of 300～450℃and the strain rate of 0.01～10 s-1.The results reveal that the flow stress of 2024 Ahas a nonlinear relationship with temperature,strain rate and strain,where it is increased with the increase of strain rate and decrease of deformation temperature.The modified Arrhenius constitutive equation considering the compensation of strain and modified Johnson-Cook（M-JC）model were established based on the experimental data,respectively.Then,the statistical method was introduced to quantitatively evaluate the accuracy of the two models.The average absolute relative error（AARE）and root mean square error（RMSE）of the modified Arrhenius model are 5.02% and 5.88 MPa,and the corresponding values of the M-JC model are 3.72% and 5.27 MPa,respectively.Therefore,the prediction accuracy of M-JC model is superior to that of the modified Arrhenius model,so it can be applied to describe hot flow behavior of 2024 Aaluminum alloy during rolling process.关键词：2024A Aluminum Alloy;Flow Behavior;Arrhenius Model;Johnson-Cook Model
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发布时间：2023-12-18 - 摘要：Effects of different Fe content on microstructure and properties of hot extrusion recycled aluminum alloy were investigated by optical microscopy,scanning electron microscopy,universal tensile machine and microhardness tester.Meanwhile,the evolution mechanism of iron-rich phase morphology was also described.The results show that the increase of Fe content is beneficial to suppress grain growth during extrusion and high temperature heat treatment process.Therefore the grain size is decreased gradually with Fe content increase,and the maximum decrease degree is reached to 25%.After hot extrusion,the iron-rich phase in the regenerated aluminum is broken and distributed in a strip shape along the extrusion direction.With the increase of Fe content,the area fraction and average length of iron-rich intermetallic phase are gradually increased,then area fraction and average length reach the maximum value when Fe content is 0.10%～1.24%,respectively,however,the roundness of the iron-rich phase is reduced slightly with the Fe content increase.Meanwhile,the tensile strength,yield strength and elongation of recycled aluminum present a decreasing trend with the increase of Fe,where maximum amplitude reach about 10.4%,23.2%and 46.0%,respectively,while the microhardness is increased gradually to21.7%.The fracture morphology is changed from a pure ductile fracture to a mixed fracture mode.关键词：Recycled Aluminium Alloy;Hot Extrusion;Iron Content;Iron Rich Phase
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发布时间：2023-12-18 - 摘要：<正>中国工业机器人产量规模分析中投产业研究院发布的《2020～2024年中国机器人产业投资分析及前景预测报告》显示,2019年1～12月,全国工业机器人累计产量为18.69万套,同比降低了6.1%。其中,12月份工业机器人产量最高,为2万套,同比增长了15.3%;其次是11月份,单月产量为1.61万套,同比增长了4.3%。《2020～2024年中国机器人产业投资分析及前景预测报告》显示,经济因素、技术因素和政策因素是我国机器人发展的主要推动力:机器人下游应用领域不断拓展,技术逐步成熟,
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发布时间：2023-12-18 - 摘要：<正>柳州市重点项目——柳州上汽汽车变速器有限公司七速双离合自动变速器项目已复工,其中DCT380项目产线正在进行调试。首款DCT七速双离合自动变速器将为北京汽车配套,目前已获得首批2 000台订单。据了解,此次建设的七速双离合自动变速器项目位于柳州阳和工业新区,投资3亿元,主要为上汽通用五菱配套生产汽车变速器,年产能可达30万台产能。据悉,柳州上汽基地厂房建筑面积18 144 m2,汽车变速器总成装配线3条,年设计装配能力为80万台,主要为上汽通用五菱以及扩展到西南地区的整车生产企业配套汽
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发布时间：2023-12-18 - 摘要：<正>近日,广东文灿压铸股份有限公司（"文灿股份"）发布公告称,其拟使用闲置募集资金暂时补充流动资金的金额为不超过人民币50 000万元,使用期限自公司董事会审议通过之日起不超过12个月,到期前将归还至公司募集资金专户。2019年,文灿股份公开发行可转换公司债券,募集78 639.79万元,将用于"新能源汽车电机壳体、底盘及车身结构件智能制造项目","天津雄邦压铸有限公司精密加工智能制造项目","大型精密模具设计与制造项目","文灿股份研发中心及信息化项目"。截止2020年3月24日,本次
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发布时间：2023-12-18 - 摘要：<正>邯郸二宁禾科技股份有限公司年产50万模基于半固态成形技术的铝镁合金制品产业化项目,经过两年时间的建设,公司已于近日正式投产。并被河北省发改委认定为"2020年第一批省高技术产业化项目",并获得600万元资金支持。据了解,邯郸二宁禾公司项目位于峰峰矿区经济开发区,项目新增建筑面积10 216m2,购置全自动半固态金属制备设备、熔化炉、转运炉、压铸机、机加工中心等生产和辅助设备,建设基于半固态成形技术的铝镁合金制造生产线。项目全部启动后,将形成年产50万件铝镁合金制品。此次建设的半固态成形技术是通过改变铝镁合金的金相,制备出低成本、高质量的铝镁合金产品。该工艺明显改善铝镁合金制品的性能,有助于增强我国在航空、汽车等工业水平的提高和在国际市场上竞争能力。
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发布时间：2023-12-18 - 摘要：<正>近日,国务院联防联控机制在北京召开新闻发布会,工信部信息通信管理局局长韩夏在会上表示,通过实施网络强国战略和大规模的通信网络建设,目前中国已经全面建成了光网城市,4G基站的总规模达到了548.8万个,行政村光纤通达率、4G通达率都超过了98%。多年持续通信建设,让中国的网络基础设施全球领先。疫情期间,新建的4G和5G基站超过6.3万个,进一步提升了网络的能力,夯实了通信服务保障的网络基础。韩夏指出,新型网络基础设施规模部署为新业态提供了有力支撑。像云办公、云教学、云医疗等等网络新业态的
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发布时间：2023-12-18 - 摘要：<正>近日,比亚迪与丰田电动车合资公司——比亚迪丰田电动车科技有限公司正式注册成立,注册地位于广东深圳。合资公司经营范围为纯电动车及其衍生车辆,包括纯电动汽车以及衍生车辆用零部件的设计、开发。据了解,比亚迪丰田合资公司注册资本为3.45亿元,比亚迪股份有限公司和丰田汽车公司各持股50%。按照此前双方签订的合约,未来双方将共同开发轿车和低底盘SUV的纯电动车型,以及上述产品等所需的动力电池。车型将使用丰田品牌,产品计划于2025年前投放中国市场。在2019年7月,比亚迪发布公告宣布与丰田汽车有限公司达成合作,共同探讨纯电动车及动力电池的开发。当年11月,双方就成立纯电动车的研发公司签订合资协议。到2020年3月,新公司正式注册成立,意味着合资公司进入实质性阶段。
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发布时间：2023-12-18 - 摘要：<正>目前国内新冠疫情基本得到控制,各地正积极、有序地进行复工和复产,但海外疫情形势依然严峻。疫情在全球的蔓延,对全球铝产业链带来了较大的影响。我国海外铝土矿项目主要分布在几内亚、澳大利亚、印尼、巴西、印度、马来西亚、加纳等国家,从目前疫情发展情况来看,几内亚、加纳等非洲国家疫情情况暂稳,虽然目前疫情尚未引起生产端发生变化,但若疫情不能得到及时有效的控制,后期可能会对港口、船运造成影响。未来市场将受主产地疫情的发展情况,以及下游电解铝产能的变动情况影响,后续还需多加关注。电解铝方面目前海外生产端没有传出因疫情导致的减停产消息。
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发布时间：2023-12-18 - 摘要：<正>随着5G手机的上市,5G手机普及的浪潮越来越近。据业内认识预测,2020年下半年将迎来5G终端的规模发展期,手机、泛终端产品将呈爆发式增长。为迎接5G终端规模化量产,配套厂家在2019年纷纷布局,建立自动化生产线。2019年5月,东莞茂伟电子有限公司购入了伊之密十余套DM300H压铸机及周边自动化配套系列,用于生产4G、5G手机中板。根据茂伟电子的产品需求,伊之密提供了全伺服三手系列（给汤机、喷雾机、取件机）实现全自动生产。对比人工操作,该全自动生产方案更稳定,产品合格率和生产效率更高,并节省人力成本。在手机中板自动化生产中,喷雾是较为重要的一环。喷雾过多,产品表面会出现发黑、水纹等现象;喷雾过少,产品可能难以脱模,从而造成拉伤产品。更为关键的是,对于厚度约0.3 mm的5G手机中板
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发布时间：2023-12-18 - 摘要：<正>温州市瓯海区生态环境分局于近日拟对浙江凯迪仕实业有限公司年产100万把智能锁具迁建项目环评申请审批。据介绍,此次搬迁新建设地址系原厂房租赁合同到期,拟将厂房整体搬迁至现建设地温州市瓯海区郭溪街道富豪路32号（瓯海高新技术眼镜产业园8幢）重新组织,从事智能锁具生产。据了解,此次建设项目是租用温州市瓯海经济开发区建设投资有限公司闲置厂房,占地面积7 584平方米,建筑面积约28 442m2,生产设备除锁体车间内新增加部分旋铆机、自动选码机等,生产规模为年产100万把智能锁具。项目总投资约1 000万元,预计2020年6月建成投产。
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发布时间：2023-12-18 - 摘要：In-situ formation of Ta-rich reinforced Zr-Cu amorphous matrix composites was performed by dealloying method.The difference of the second phase in composites prepared by the conventional arc-melting method and novel dealloying method was analyzed comparatively,and effects of dealloying on the second phase at different temperatures were expounded comparatively.Compared with that in the composites prepared by the conventional arc-melting method,the second phase in the composites prepared by the dealloying method presents finer in size,higher number density and larger in unit interface area,which is beneficial to the improvement of strength and plasticity.Meanwhile,as the dealloying reaction temperature increases,the size and volume content of the second phase are decreased,and hardness of the amorphous matrix and the second phase are increased.关键词：Amorphous Alloy;Composites;Dealloying;In-situ
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发布时间：2023-12-18 - 摘要：Due to aging of sodium silicate sand after mixing,it can reduce its strength,collapsibility,moisture resistance and so on.Sodium silicate was modified in an ultrasonic processor with a frequency of 40 kHz and a power of 480 Wto test its performance.The results show that the viscosity of sodium silicate is decreased with the increase of ultrasonic treatment time.At 30 min,the viscosity of sodium silicate is decreased by 11%,and the wettability of sodium silicate is increased by 13%～37% compared with that of ones before modification.The dry strength of sodium silicate sand is increased by 48%.At the same time,the residual strength of sodium silicate sand at high temperature is decreased by 41%,and the hygroscopicity of sodium silicate sand prepared by mixing sodium silicate sand before and after ultrasonic modification is increased by 8%.The results show that ultrasonic treatment can improve the strength and hygroscopicity of sodium silicate sand,and improve the collapsibility of moulding sand as well as reducing the amount of sodium silicate.关键词：Water Glass;Aging;Ultrasonic Modification
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发布时间：2023-12-18 - 摘要：The research status and the superplastic forming technologies of amorphous alloys were introduced briefly,focusing on the influences of temperature and strain rate on the superplasticity of amorphous alloys,as well as the constitutive model of supercooled liquid zone and application of superplastic forming processes.The problems that need to be solved in the research of superplasticity of amorphous alloys were proposed.关键词：Amorphous Alloys;Superplasticity;Supercooled Liquid Region
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发布时间：2023-12-18 - 摘要：Because of its unique two-dimensional structure and excellent physical,chemical properties,graphene has great potential effects in improving the mechanical behavior,electrical and thermal properties of the composites,and it has become the most ideal reinforcement of metal matrix composites.Copper metal has excellent thermal conductivity and good ductility,however its low strength,non-wear resistance and high temperature deformation characteristics seriously hinder its application and development in industry fields.Therefore,combining the properties of graphene with copper,it has become one of the hotspots in the research of composites through adding graphene as reinforcement to copper to prepare graphene reinforced copper matrix composites with excellent properties.The preparation methods of graphene copper matrix composites were reviewed,and the characteristics of each method was analyzed comparatively,and the future trendency of preparation technology was put forward.The problems and challenges in the preparation of graphene reinforced copper matrix composites were described,and the possible research directions in the future were prospected.关键词：Graphene;Copper Matrix Composites;Preparation Method;Dispersion;Wettability
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发布时间：2023-12-18 - 摘要：The tensile and shear behaviors of Al3Ti single crystal were analyzed by molecular dynamic method.The deformation processes of Al3Ti were simulated at room temperature and constant strain rate,and the effects of temperature and strain rate on the tensile and shear properties of the system were described.The results reveal that Al3Ti shows brittle characteristics at room temperature,and the rapid development of voids and dislocations produced by Al3Ti in a short period of time after the elastic deformation stage is responsible for material failure.With the increase of temperature,mechanical properties of the single crystal Al3Ti,such as tensile strength and Young’s modulus,shear strength and shear modulus,are decreased,while with the increase of strain rate,the tensile strength and shear strength of the Al3Ti are improved,and the Young’s modulus and shear modulus are independent.关键词：Molecular Dynamics;Al3Ti;Mechanical Properties;Temperature;Strain Rate
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发布时间：2023-12-18 - 摘要：A mathematical model was established to describe the behavior of molten steel jet flow and steel/slag interface fluctuation with EMBR ruler.The effects of different electromagnetic parameters on the behavior of molten steel jet flow and steel/slag interface fluctuation were investigated by numerical simulation.The influence of magnetic induction intensity,the change of distance between the level electromagnetic pole and submergence depth of SEN was analyzed on the behavior of molten steel jet flow and steel/slag interface fluctuation.The results reveal that the application of EMBr ruler can control effectively the molten steel jet flow,and reduce the velocity of upward backflow and downward backflow as well as stabilizing the fluctuation of molten steel and liquid slag interface when the electromagnetic field of EMBr ruler coveres the jet flow impact region,upward backflow and downward backflow zone（D=20 mm）at the same time.For a long distance between the level electromagnetic pole and submergence depth of SEN（D=220 mm）,the molten steel velocity of upward backflow in the mold can′t be depressed by increasing the magnetic induction intensity.A higher magnetic induction intensity isn’t conductive to stabilize the fluctuation of molten steel and liquid slag interface,and the probability of slag entrapment is increased.关键词：Electromagnetic Brake;Molten Steel Jet Flow;Steel-slag Interface
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发布时间：2023-12-18 - 摘要：Low-pressure casting red copper crystallizer was analyzed,focusing on the design of sand mould,melting of red copper.In sand mould,the resin was adopted as adhesive,and the moisture content of the sand mould is 8% with the permeability in liquid above 70 Pa and green compression strength of 0.02～0.03 MPa,dry tensile strength of 0.1～0.2 MPa as well as baking the core.In addition,the highest furnace temperature is 180～200℃,and melting in intermediate frequency induction electric furnace with temperature of 1 200～1 220℃and deoxidization casting.The amount of the deoxidization phosphor-copper is below 0.05% with adopting the vacuum degassing.关键词：Red Copper;Sand Mould;Low-pressure Casting
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发布时间：2023-12-18 - 摘要：By using OM,SEM,ICP analysis,microstructure and phase composition of ADC12 die casting aluminum alloy were investigated,and the stress distribution of the pedestal during scram operation of the robot was analyzed by using FEM simulation.The results reveal that lots of defects are generated in the structure of ADC12 die casting aluminum alloy during casting process,such as shrinkage cavity,segregation and segregation tumors,especially in the bend area.The mechanical properties of the alloy are decreased seriously due to the microstructure defect.In addition,there exists a stress concentration at the junction between the front and rear of the base and the platform.Therefore,the comprehensive influence of the casting defects and stress concentration during scram operation results in cracking failure of the ADC12 die casting aluminum alloy pedestal.关键词：ADC12 Aluminum Alloy;Microstructure Defect;Stress Concentration;Cracking Mechanism
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发布时间：2023-12-18 - 摘要：Mg93YZn6 alloy was prepared by squeeze casting,and then it was treated by heat treatment at high temperature.The microstructure,microhardness and mechanical properties of the as-cast and heat-treated Mg93YZn6 alloy were analyzed by OM,SEM and tensile testing.The results reveal that theα-Mg matrix and the qusaicrystal I-phase are generated in the microstructure after squeeze casting and heat treatment.After heat treatment at 500℃for 4 h,the content of quasicrystal phase can be ignored for change in the as-cast alloy.The quasicrystal phase is decreased after heat treatment at 550℃for 2 h.Compared with those of the as-cast alloy,the hardness,tensile strength and elongation of the alloy are all improved,especially elongation after heat treatment.关键词：Mg93YZn6 Alloy;Quasicrystal;Squeeze Casting;Heat Treatment;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Based on the vacuum die casting aluminum shock tower developed for Al arc welding platform vehicle body,process modified methods were analyzed,and mechanical performance of the shock tower was evaluated.The results reveal that through increasing the density of aluminum liquid,reducing the Mg content,optimizing heat treatment,the mechanical properties of shock tower can be improved greatly.After T7 temper,the yield strength,tensile strength and elongation of the modified shock tower reach 128.92 MPa,216.18 MPa which is12.14% higher than previous trial-producet and 11.5% which is 56.89% higher than previous trial-producet,respectively,and the density is 2.682 1 g/cm3,meeting the requirements of design and application.In addition,the welding filler of ER4043 and ER5356 was used to evaluate the welding performance of shock tower.The strength of ER5356 welding joint is more than 160 MPa,and efficiency of welding joint reaches 76%,which is superior to that of ER4043.关键词：Vacuum Die Casting;Shock Tower;Arc Welding;AlSi10MgMn Alloy
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发布时间：2023-12-18 - 摘要：Based on CATIA,the sub-frame structure and pouring system were designed,and the finite element model of the sub-frame was established to analyze the stiffness,strength and mode of the sub-frame.The ProCAST software was used to simulate the low-pressure casting process of the sub-frame.The reliable durability of the integral hollow aluminum alloy sub-frame produced by low pressure casting was verified.The results show that the low pressure casting sub-frame meets the performance requirements.关键词：Low Pressure Casting;Integral Hollow;Aluminum Alloy Sub-frame;Numerical Simulation;Experimental Verification
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发布时间：2023-12-18 - 摘要：Taking the middle plate as an example,the main difficulties in the machining of thin-wall plate-like die casting parts were described,and the machining scheme during development was analyzed to find out the control points to ensure the machining precision of the thin-wall plate-like parts,and to improve the quality of the process development.During the trial production,through data analysis,it is found that the thermal deformation of CNC machine results in insufficient process capability of machining holes.The error compensation method was adopted to solve the problems,so that the rejected parts with poor position accuracy were eliminated.关键词：Thin-wall Plate-like Parts;Deformation;Thermal Deformation of Machine;Error Compensation
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发布时间：2023-12-18 - 摘要：Columnar crystal Cu-Al-Be shape memory alloy rods were prepared by vertical Ohno continuous casting technology,in which the Mfwas below-50℃,and the columnar crystal growth direction presented the axial direction.The samples which are normal polycrystalline or parallel to the columnar crystal direction or perpendicular to the columnar crystal direction were compressed in single direction under a low temperature condition below the Mf.The image along the growth direction and fracture morphology of the columnar crystal were observed by optical microscope（OM）and SEM.The results reveal that the microstructure of the columnar Cu-Al-Be alloy rod is similar to that of the hierarchical structures of nacre and the fracture morphology is similar too.In addition,the sample perpendicular to the columnar crystal direction presents the desirable plasticity and the highest absorption energy before fracture,showing the desirable comprehensive performance.关键词：Columnar Crystal;Cu-Al-Be Shape Memory Alloy;Low Temperature Compression;Fracture Mecha-nism;Hierarchical Structures of Nacre
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发布时间：2023-12-18 - 摘要：A selective laser melting technology was used to form TC4 samples.The effects of scan line power,exposure time and annealing process on the microstructure and properties of TC4 sample were investigated.The microstructure,section morphology and mechanical properties of the samples before and after heat treatment were analyzed.The results show that the defects of sample are decreased with the increase of scan line power.The tensile strength of the sample after annealing reaches 1 153 MPa,which is nearly 300 MPa higher than that of ordinary forging TC4 titanium alloy when the power of the scan line is 400 Wand the exposure time is 30μs.The tensile fracture of the sample presents brittle crack.关键词：Selective Laser Melting;Annealing Treatment;Mechanical Properties;TC4Titanium Alloy
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发布时间：2023-12-18 - 摘要：A self-lubricating composites filled with polytetrafluoroethylene with AlSi10 Mg as the matrix was prepared by selective laser melting（SLM）,impregnation and vacuum sintering.The friction and wear behavior were investigated by reciprocating Bruker UMT-3 friction tester under different loads（10,30,50,70 N）at a given speed（5 mm/s）.The composition and structure of the composites prepared were characterized by SEM and EDS.The tribological behavior test was carried out on a ball-on-disc mode.The results reveal that the average friction coefficient and wear rate of the composites are increased firstly and then decreased with the increase of the load.The friction stability of the composite is mainly determined by the PTFE stored in the skeleton.The friction mechanism is mainly that when the friction surface is worn under the action of load,the PTFE stored in the skeleton will capture the abrasive debris to form a complete PTFE lubrication film,and to transfer the film,thus increasing the tribological stability of the composites.关键词：AlSi10Mg;Selective Laser Melting（SLM）;Polytetrafluoroethylene（PTFE）;Self-lubricating Friction Material
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发布时间：2023-12-18 - 摘要：B4Cp/Al composites were prepared by electromagnetic stirring technology,in which B4C particle were pretreated.The wear properties and mechanism of the composites prepared were investigated by wear test on MMW-1 Awear tester.The results reveal that the impurity metal mixed in the particles can be effectively removed by pretreatment for B4C particles.The composites prepared present the satisfied wear resistance with electric stirring intensity of 60%,stirring frequency of 20 Hz,stirring time of 15 min and particle content of 3.5%.During the wearing process,with the increase of wear time,the wear mechanism is changed from palling wear to the comprehensive effect of oxidative wear,adhesive wear and abrasive wear.关键词：Electromagnetic Stirring;B4C;AlSi9Mg;Composites;Friction Wear
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发布时间：2023-12-18 - 摘要：The macroscopic and microscopic mechanical behaviors of TiB2 particle reinforced iron matrix composites were characterized by room temperature uniaxial stretching,microhardness,nanoindentation and scanning electron microscopy.The results reveal that as the volume fraction of high modulus TiB2 particles increased from15%to 25%,the tensile strength and elastic modulus of the composites are increased from 531.0 MPa and 215.5 GPa to 659.0 MPa and 247.0 GPa,respectively,and the specific stiffness is gradually increased from 28.8 GPa·cm-3·g-1 to 34.7 GPa·cm-3·g-1,and the total elongation is decreased from 22.0% to 7.9%.The fracture mechanism undergoes the transition from ductile microporous aggregation to brittle transgranular cleavage,while the dominant strengthening mechanism might be fine grain strengthening and dislocation proliferation.关键词：TiB2 Particle;Iron-Based Composites;Nanoindentation;Fracture Mechanism
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发布时间：2023-12-18 - 摘要：During Vacuum Arc Remelting process,deeper shrinkage cavity usually appears on the top of the largesize finished titanium alloy ingot,which also causes the high discarding amount of the ends.The reasons causing shrinkage cavity were analyzed,and the principle and method to design the parameters of hot topping were described.Thus,the hot topping system suitable for the production was determined which reduced the depth of the shrinkage cavity and increased the yield rate of the finished ingot greatly.关键词：Titanimu Alloy;Vacuum Arc Remelting;Hot Topping;Depth of Shrinkage Cavity
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发布时间：2023-12-18 - 摘要：The composites of Al-50 Si,Al-60 Si and Al-70 Si alloy were prepared by hot pressing to understand effect of Si content on the microstructure and physical properties of the composites prepared.The results show that the Si content has a great influence on powder metallurgy aluminum-silicon composites.When the Si content is 50%,the Al matrix forms a continuous network structure in the composites prepared,however a large number of fine pores can be observed.When the Si content is increased to 60%,the Al matrix is distributed in a continuous network and the internal pores are reduced obviously.When the Si content reaches 70%,the probability of Si particles growing apart from each other presents more obvious,and the Si phase size is significantly increased.The Al-60 Si composites has the desirable performance with thermal conductivity of 128.0 W/（m·K）,and the thermal expansion coefficient is 9.92×10-6℃-1 from room temperature to 150℃,and the density reaches up to2.462 g/cm3.关键词：Electronic Packaging Materials;Hot Press Forming;Density;Thermal Conductivity;Thermal Expansion Coefficient
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发布时间：2023-12-18 - 摘要：The quenching sensitivity of high zinc-containing Al-Zn-Mg-Cu alloy was described under different heat treatment conditions.The results show that the hardness retention values of the high zinc-containing Al-Zn-MgCu alloy with end quenching at 120 mm are 91.26% and 96.25% after artificial aging and natural aging,respectively.With the increase of the distance from the quenched end of the specimen after artificial aging,the size of the precipitation-enhancing phase is increased with the decrease of the density,and the non-deposited precipitation band becomes wider,all of which reduce its hardness.The GP zone is the main strengthening phase of the natural aging alloy,and the density difference between the quenched end and the quenched end of the specimen is relatively low after natural aging for 1 680 h,therefore,the high zinc-containing Al-Zn-Mg-Cu alloy in this state has low quenching sensitivity.关键词：Al-Zn-Mg-Cu Alloy;Quenching Sensitivity;End-Quenching;Aging
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发布时间：2023-12-18 - 摘要：γ-TiAl based alloys were canned extruded in theα+γ phase field at near isothermal condition.The effects of extrusion temperature on the homogeneity of deformed microstructures and subsequentlyαsolid solution treated microstructures in the whole extruded rod were investigated,and room temperature tensile properties of corresponding microstructures were compared.The results reveal that the deformed microstructures in the center and edge of rod are different.The center region presents coarse near-lamellar structure,while the edge region has fine equiaxed near-γphase,which are related with the deformed temperature and inhomogeneity of deformed rate distribution.With the increase of the extruding temperature,the residual lamellar grain in the center region is decreased with the increase of recrystallized lamellar grain.With the equiaxedγ phase increasing in the deformed structure,the grain size of the lamellar structure is refined gradually,so the grain size in the alloy after solid solution is decreased,leading to the improvement of the elongation.The extruded rod at 1 280 ℃ has the homogeneous structure after solid solution,and the elongation of the alloy presents the ingronat difference in the center and edge at room temperature.关键词：γ-Tial Based Alloys;Extrusion Temperature;Microstructure;Tensile Properties;Homogeneity
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发布时间：2023-12-18 - 摘要：The effects of different La additions on structure and cooling curve of Sr modified Al-9 Si-Cu alloy were investigated.The results show that with the increase of addition of La（0～0.8%）,the size of primaryα-Al of0.02 Sr modified Al-9 Si-Cu alloy is decreased,and the minimum growth temperature Tmin-αand maximum growth temperature TG-αof primaryα-Al are increased.A small amount of La addition（0.1%～0.2%）can enhance significantly the modification effect of eutectic Si,decrease eutectic minimum temperature Tmin-siand maximum temperature TG-si,and increase eutectic recalescence temperature(ΔTR-Si).However,with the addition of a higher amount of La（0.4%～0.8%）,eutectic silicon modification effect is deteriorated,while Tmin-si、TG-siandΔTR-Siare decreased.It is found thatΔTR-Sihas a good function with the eutectic silicon modification effect,and with the increase of the ΔTR-Si,the modification effect is improved.关键词：Al-9Si-Cu;La;Sr Modification;Microstructure;Thermal Analysis
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发布时间：2023-12-18 - 摘要：<正>据外媒报道,尽管目前新型冠状病毒疫情仍在肆虐,但电动汽车制造商特斯拉仍在继续建设德国柏林工厂,其一期工程已经初见规模,特斯拉开始为大楼地基平整土地。按预定计划,特斯拉拟定于2020年3月开始建设第一座大楼,并准备在本年度7月21日之前投产。项目位于GVZ Berlin-Ost Freienbrink工业园区附近,占地300公顷。2019年,特斯拉柏林工厂的计划泄露,包括了工厂整体结构图,按照数字序号依次为电池和驱动单元制造、座椅制造、总装、油漆车间、中央供应楼、高架仓库、废水处理、车体构造、塑料生产/冲压车间/铸造、新火车站、测试赛道、运送和收集以及停车场。
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发布时间：2023-12-18 - 摘要：The effects of drawing deformation on the microstructure,mechanical properties and electrical properties of hard copper rolling rod and drawing rod were investigated by means of optical microscope,universal testing machine and resistor.The results show that with the increase of drawing deformation,the tensile strength of hard copper rolling rod is decreased slightly firstly and then increased,while the electric conductivity is decreased.The tensile strength of the drawing rod is increased,and electric conductivity keeps stable at first and then decreased slightly.When the drawing deformation is more than or equal to 70%,the tensile strength and conductivity of the single wire drawn by the hard copper drawing rod are superior to that of the rolling rod.The electrical and mechanical properties of hard copper single wire drawn by drawing rod are relatively stable and meet the requirements of TB/T3111-2017 standard.关键词：Hard Copper Drawing Rod and Rolling Rod;Deformation;Grain Orientation;Tensile Strength;Conductivity
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发布时间：2023-12-18
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