最新刊期
卷 39 ， 期 7 ， 2019
- 摘要：The first-principles molecular dynamics method was used to simulate the formation process of alumina inclusions by the anode gas mass transfer to the aluminum liquid.The results show that in electrolytic aluminum,CO2 is dissociated into CO and O,and aluminum is oxidized.The relative barrier change of the reaction process is the initial structure（0 Ha）→transition stateⅠ（0.019 Ha）→intermediate state（0.030 Ha）→transition stateⅡ（-0.042 Ha）→end of reaction（-0.056 Ha）.The reaction process between CO2 and electrolytic aluminum solution is:CO2→CO2（ad）→COad+[O]→CO↑+[O],3[O]+2Al→Al2O3.The total reaction is:3CO2+2Al→Al2O3+3CO↑.The aluminum oxide bond formed by the combination of the dissociated product oxygen and aluminum is very stable.Pure aluminum was prepared by using electrolytic aluminum as raw material.The microstructure of the solidified sample was observed by scanning electron microscopy.For high-temperature electrolytic aluminum liquid,the anode gas is a very strong oxidant,which can react with high-temperature aluminum liquid to form alumina inclusions.The oxidation inclusions in the electrolytic aluminum solution have a metallurgical genetic influence on the alloy structure.The oxidation inclusions are accumulated within the samples,and the surrounding pores are relatively developed,indicating that the gas passes through the oxidized inclusion nucleation and grows up.关键词：Liquid Aluminum;Anode Gas;Alumina Inclusion;Mass transfer;Molecular Dynamics Method
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发布时间：2024-04-01 - 摘要：(TiC)x/AlCr2FeNi2Cu1.6 high entropy alloy matrix composites were prepared by vacuum arc furnace.The effect of TiC content on microstructure and mechanical properties of AlCr2FeNi2Cu1.6 high entropy alloy was analyzed.The results show that（TiC）x/AlCr2FeNi2Cu1.6 high entropy alloy composites are composed of FCC phase and BCC phase.The addition of TiC powder does not change the phase structure of high entropy alloy.However,with the addition of TiC,the diffraction peaks of TiC appear in the alloy.The FCC phase contains more Cu,Al,Ni elements and the BCC phase contains more Fe,Cr elements in the high entropy alloy.With the addition of TiC,new Al,Ni and Cu phase which contaion TiC appeared in the alloy.The compressive yield strength and fracture strength of high entropy alloy is increased firstly and then decreased with the addition of TiC.When the content of TiC is 7.5%,the yield strength and fracture strength of alloy are relatively higher,and the compressive strain is decreased rapidly to 8.32%.关键词：High Entropy Alloy;Composites;Microstructure;Mechanical Properties;TiC Powder
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发布时间：2024-04-01 - 摘要：Diamond-like carbon films were prepared on three different substrates,such as stainless steel,aluminium alloy and silicon nitride,by plasma enhanced chemical vapor deposition（PECVD）using tetramethylsilane as the reaction source,and the performance of the films was evaluated.The surface morphology and structure of the films prepared were analyzed by atomic force microscopy（AFM）and Raman spectroscopy（Raman）,respectively.The hardness and elastic modulus of the films were measured by nanoindentation technique.The mechanical properties of the films were measured by friction and wear tester.The results of AFM characterization show that the deposited films present amorphous structure.Raman spectroscopy analysis shows that the deposited films belong to diamond-like films.DLC films can be prepared on non-metallic substrates by plasma chemical vapor deposition technology.DLC films on three substrates have compact structure,smooth surface and good uniformity.Compared with those of ones on aluminium alloy and silicon nitride,the hardness and elasticity modulus of the film on stainless steel as the substrate are less different from that of the substrate,and the stronger adhesion between the film and the substrate can be observed,reaching 13.55 N.The friction coefficient of the film with silicon nitride as the substrate is 0.094 8,however the adhesion of the film with silicon nitride as the substrate is poor,only 6.63 N.In addition,under the same experimental conditions,the composition and wear resistance of the films can be affected significantly by the type of substrates,while the surface morphology and roughness of the films are affected slightly.关键词：DLC;PE-CVD Technology;Doping;Raman;AFM
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发布时间：2024-04-01 - 摘要：The influence of lanthanum（Y）content on microstructure and mechanical properties of the as-cast and extruded Mg-Zn-Y alloys was investigated systematically.By casting and extruding Mg-Zn-Zr-Y alloys with different Y contents and performing metallographic microscopic analysis,it is found that Y can change the composition,morphology and distribution of the second phase in the magnesium alloy,and refine the grain size.Meanwhile,the mechanical properties of Mg-Zn-Zr-Y alloy were measured.The results reveal that the W phase of the ternary compound introduced by Y is broken and dispersed in the alloy during hot extrusion process,so that the alloy finally obtains a fine grain structure with a size of 5～7μm,greatly improving the mechanical properties of the magnesium alloy.关键词：Rare Earth Element;Extrusion;Fine Grain Structure;Mechanical Properties
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发布时间：2024-04-01 - 摘要：The effects of different Cu content（0,0.05,01,0.2）on the corrosion behavior of Zr-1 Nb-0.1 Fe alloy sheet with thickness of 1.4 mm at 400 ℃for 10.3 MPa super-heated steam were investigated,and the optimum Cu content was determined to design the alloys with excellent performance.The microstructure,distribution and size of the second phase of the samples were observed by OM and SEM,meanwhile,the size and distribution of the second phase were analyzed by Image-Pro software.The role of Cu content in the corrosion mechanism of the samples under 400℃/10.3 MPa was undersatnd.The results reveal that a certain amount of Cu addition can generate homogeneous,fine and dispersive second phase in Zr-1 Nb-0.1 Fe alloy,improving the corrosion resistance of the samples.It is demonstrated that Cu,either in the form of solid solution or in second phase,will enhance the corrosion resistance of zircaloy.关键词：Zr-Nb-Fe-Cu Alloy;Corrosion;Microstructure;Second Phase
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发布时间：2024-04-01 - 摘要：The solidification cooling curve of Al-6.5 Mg-0.14 Ti-0.12 Zr is distributed according with the Logarithm function,which presents as paste solidification easily due to the temperature interval of 111.4℃.The investment mold obtains the highest cooling rate,which is higher than the resin sand and plaster mold.Absence of casting/mold interface reaction can be observed during the solidification process,and the alloy has excellent filling capability,which can fill completely the different molds.The as-cast microstructure of the alloy is composed ofα-Al phase and Al3Mg2 phase,and the Al3Mg2 phase is distributed uniformly along the grain boundary.The average size ofα-Al phase can be reduced from 324μm to 132μm in resin casting compared with that of ones in plaster mold casting.The average tensile strength,yield strength,elongation and Vickers hardness of investment casting samples reach up to 274.7 MPa、136 MPa、14.9% and 60 HV,respectively.After the solid solution treatment at 400℃for 12 h,the average tensile strength,yield strength,elongation and Vickers hardness of the investment casting samples are increased to 322.7 MPa、144 MPa、31.9% and 68.3 HV,respectively.The as-cast fracture is presented absolutely crystal fracture,and some micro-dimples can be observed.The rupture mode is changed to dimple fracture after the solution treatment,and small Al3Mg2 phase,Al3Ti phase and Al3Zr phase particles are generated in the dimple.关键词：Al-Mg Alloy;Solidification and Cooling;Microstructure;Mechanical Properties
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发布时间：2024-04-01 - 摘要：The alloy was melted by medium frequency induction furnace,and the test blocks of non-magnetic austenite stainless steel were poured by investment casting.By metallographic microscope,X-ray diffractometer,Instron 5882 universal material testing machine and vibrating sample magnetometer,the microstructure,mechanical properties and relative permeability of 304 austenitic stainless steel at as-cast and solid solution conditions were analyzed.Then,based on the experimental results of previous 304 austenitic stainless steel,a type of new as-cast non-magnetic austenitic stainless steel was prepared by changing the content of main alloy elements such as Mn,Ni and Cu.The results demonstrate that the relative permeability of solid solution（1 200℃×4 h）304 austenitic stainless steel sample is 1.008 7,which meets the requirements of non-magnetic materials（μr≤1.02）,presenting the satisfied mechanical properties.The as-cast new austenitic stainless steel is non-magnetic material with relative permeability 1.006 6 and desirable mechanical properties.关键词：304 Stainless Steel;Solution Treatment;Chemical Composition;Relative Permeability
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发布时间：2024-04-01 - 摘要：The effects of 0.4% and 0.8% Mn element content on the tensile strength and yield strength of highsaturation Al-8Zn-1.8Mg-1.4Cu alloy forgings were investigated by means of transmission electron microscopy,high resolution transmission electron microscopy,room temperature tensile testing and JMatPro software.The results reveal that with 0.4% and 0.8% Mn addition,the tensile strength of the Al-8Zn-1.8Mg-1.4Cu alloy reaches 545 MPa and 553 MPa,respectively,which is increased by 7.9%and 9.5%compared with that of the matrix alloy,and the yield strength reaches 448 MPa and 469 MPa,which is increased by 16.3% and 17.4% compared with that of the matrix alloy.The Al6Mn precipitate phase can be formed in the solution heat treatment alloy with the Mn addition after solid solution and ageing treatment,where the Al6Mn precipitate phase exists in the shape of a rod inside and outside the grains,and the amounts are increased with the increase of the Mn content.In addition,the precipitated phase of Al6Mn exists in a non-coherent form with the aluminum matrix after solution heat treatment,and the strength of the alloy is enhanced by dispersion of Al6Mn phases.The Mn atom can replace the Al atom in the aluminum matrix,resulting in the lattice expansion of the face-centered cubic aluminum matrix and the lattice constant increase,so leading to lattice distortion and solid solution strengthening.关键词：Mn;Al-8Zn-1.8Mg-1.4Cu Alloy;HRTEM Diffusion Strengthening;Solution Strengthening;Tensile Strength
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发布时间：2024-04-01 - 摘要：<正>近日,沙特军事工业公司（SAMI）与全球知名航空部件制造供应商法国Figeac Aero公司在巴黎航展签署协议备忘录,拟在沙建立一家合资工厂生产军用和商用航空金属部件,SAMI持多数股份。新工厂将位于利雅得或吉达,项目合同为期两年半。工程师和技术人员需经严格培训,从事钣金加工、表面工艺处理和零部件装配等自动化操作,并将成品交付给客户。受益于航空制造业资格许可,该工
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发布时间：2024-04-01 - 摘要：<正>力拓表示公司已开发出一种铝合金,可使车轮减重7%,同时将车轮强度提高15%～20%。公司将其称之为"Revolution-Al",隶属于3xx系列高强度合金。力拓对新产品秉承:外观上,增强视觉效果;性能上,提高车辆操纵性和机动性,减少二氧化碳排放量及轮胎磨损度,保证与现有铸造工艺无缝过渡。另外,与传统的A356.2合金相比,该合金还可延长使用时限。
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发布时间：2024-04-01 - 摘要：<正>2019年6月26日,中信戴卡摩洛哥铝车轮生产基地投产仪式在摩洛哥举行,标志着北非地区首家中国品牌的铝合金车轮产品将从这里生产,发往全球。中信戴卡摩洛哥铝车轮生产基地位于摩洛哥西北部的海口城市盖尼特拉,总占地面积约5万m2。截至目前,这一项目已为当地创造约600个就业岗位,该基地铝车轮年产量近300万件。2019年5月25日,北非地区第一只中国品牌的成品铝合金车轮从这里生产下线。未来,安全、轻量、环保、高品质的中国品牌铝合金车轮产品将从这里源源不断地发往全球。
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发布时间：2024-04-01 - 摘要：<正>国际铝业协会数据显示,2019年5月份全球氧化铝产量约为1 020万t,环比小幅增加约0.1%,同比减少0.7%。今年1～5月份全球氧化铝产量累计约为5 060万t,较去年同期增加约1.2%。数据显示,5月份中国氧化铝产量约为556万t,环比减少约3.5%;大洋洲氧化铝产量约173万t,环比增加约4.1%;非洲和亚洲（除中国）氧化铝产量约为84.3万t,环比增加约13.6%;南美洲氧化铝产量约为74.3万t,环比增
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发布时间：2024-04-01 - 摘要：The casting process of aluminum alloy piston for a gasoline engine was simulated by Magma software.The mould was optimized according to the types and location of casting defects.The results reveal that the liquid aluminum storage tank on the front end of top die can avoid the liquid aluminum that is easily oxidized in front remaining on the top,so as to reduce the air hole defects caused by poor exhausting of the mold when the aluminum liquid is filled to the top surface.The consistency between the simulated results and the actual production has been verified by dyeing and CT scanning technology.Through small batch production verification,piston top casting defects has been reduced from 50%to less than 5%,solving effectively the casting defects on the top surface and improving the product quality.关键词：Piston;Gasoline Engine;Numerical Simulation;Casting
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发布时间：2024-04-01 - 摘要：According to the structural characteristics of the filter housing,the die casting process was designed.The Flow-3 Dsoftware was used to simulate the die casting process,and position of the defect was predicted based on the distribution of the entrained air.The simulated results of the initial scheme reveal that there exist more entrained air in the middle and both ends of the cavity,resulting in defects such as blowholes and shrinkage porosity.It is judged by the temperature field distribution that the solidification mode of the die casting belongs to solidified layer by layer,indicating the reasonable filling process.Through adjusting the shape and position of the gating system,the ability of the over-flowing slots to collect entrained air was enhanced.The results reveal that the entrained air in the filter housing is reduced significantly,and the defects are eliminated,meeting production requirements.关键词：Die Casting;Numerical Simulation;Process Optimization;Fiter Housing
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发布时间：2024-04-01 - 摘要：Flow-3 Dsoftware was carried out to simulate the filling process of casting parts with three type of structures in low pressure die casting（LPDC）process.The influence of the pressurization rate and structure of the castings on the volume of entrained air were investigated.Based on the simulated results,the models with big volume of entrained air and most smoothly filling process were selected and produced in the factory.Tensile samples were prepared and the relationship of the air entrainment and mechanical properties were analyzed.关键词：Numerical Simulation;LPDC;Gas Entrainment;Mechanical Properties
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发布时间：2024-04-01 - 摘要：The defects in die-casting rocker arm chamber were investigated,and the origination of the shrinkage and gas leakage was analyzed.The internal shrinkage condition of the rocker arm chamber was improved by applying new local pressurization technology.The results reveal that the quality of the die castings is much better after using new local pressurization,and the oil passage gas leakage rate of the rocker arm chamber is reduced greatly from 18.7%to 0.6%,decreasing greatly cost.关键词：Rocker Arm Chamber;Die Casting;Local Pressurization;Gas Leakage
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发布时间：2024-04-01 - 摘要：Transient fluctuations of liquid slag layer and the slag entrainment in continuous casting mould were simulated by large eddy simulation（LES）.The accuracy of the mathematical models was also verified through the water simulation experiments.The effects of operating conditions on the fluctuation of the slag layer,bare "slag eye" region and the size distributions of slag droplets were analyzed quantitatively.The results show that casting speed has a significant effect on the fluctuation of the slag layer in the continuous casting mould.With the increase of casting speed,the peaks of the fluctuation are moved from the narrow wall of the mould toward the SEN,and the regions of "slag eye" is changed from the asymmetric distribution to the " open" conditions.Meanwhile,the size distributions of entrained slag droplets become wider.SEN insertion depth presents the great effects on the fluctuation of the slag layer,the change of "slag eye" region and the distribution of slag droplet size in the continuous casting mould.关键词：Large Eddy Simulation;Continuous Casting;Mould
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发布时间：2024-04-01 - 摘要：The thickness of the solidified shell at different casting speeds was measured by the nail-shooting method.The solidification heat transfer model of the round billet was established and the growth curve of the solid shell was calculated.Based on the results of the nail-shooting experiment and the mathematical model,the optimized installation position of the final electromagnetic stirring（F-EMS）should be located at 10.23 mfrom the mold level.In consideration of plant conditions for the continuous casting of SWRH82 Bhigh carbon steel,the FEMS installation position was moved from 11.1 mto 9.75 mfrom the meniscus.The results show that after the process parameters optimization,the equiaxed crystal ratio in SWRH82 Bround billet is increased from 40%～46% before optimization to 50%～64%,and the central carbon segregation index is decreased from 1.08～1.10 before optimization to 1.04～1.06.The quality of continuous casting round billets has been improved significantly.Through tracking the quality of the rolled sheet,it is found that the network carbide in the SWRH82 Bwire rod is reduced,which indicates that the quality of the rolled sheet is improved greatly.关键词：Continuous Casting;Solidification;Center Segregation;Electromagnetic Stirring
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发布时间：2024-04-01 - 摘要：<正>近日,贵州航天所属航天风华公司与中科院等单位联合申报的《新型高性能镁合金及其关键工程化技术研究》项目,荣获中国稀土学会、中国稀土行业协会稀土科学技术一等奖。航天风华公司高度重视产学研一体化建设,积极与相关高校、科研院所等展开合作,通过科研、生产、技术的强强联合,推进企业自主创新。2012年,航天风华公司与该研究所合作开展了新型镁合金铸造工艺技术应用研究,通过优化合金稀土元素成
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发布时间：2024-04-01 - 摘要：<正>7月5日,工业和信息化部发布1～5月有色金属行业运行情况。前5个月,有色金属行业运行总体平稳,效益降幅进一步收窄,行业信心有所提振。（1）生产总体平稳,价格同比回落。1～5月,我国10种有色金属产量为2 341万t,同比增长4%。其中,Cu、Al、Pb、Zn产量分别为370、1 445、238、227万t,同比分别增长4.4%、2.7%、15.8%、-0.6%。铜材、铝材产量685、2 198万t,同比增长11.7%、6.5%,增幅分别扩大2个、4.8个百分点。Cu、Al、Pb、Zn现货均价分别为48 589、13 781、17 029、22 088元/t,同比下跌6.5%、
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发布时间：2024-04-01 - 摘要：<正>山西傲天镁业有限公司消息,目前,公司落户山西转型综改示范区潇河产业园区的傲天镁业的高端镁合金产品先进制备生产项目,正在加紧建设中。该项目总投资62.5亿元,其中一期建设年产镁合金棒锭1万t,镁铝合金挤压型材8 500t、镁铝合金压铸件500万件,中间合金锭300t,镁合金终端产品30万件。傲天镁业是一家以镁合金基础材料制备及压延深加工为主,轻量化产品研发、生产、销售企
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发布时间：2024-04-01 - 摘要：<正>从OPPO智能科技有限公司获悉,OPPO（重庆）智能生态科技园目前项目一期工程约47万m2主体部分已全部完成,现厂房正在进行外墙立面、机电安装、内部装饰装修等工程施工。整个一期工程预计今年9月全面完工,10月正式投产。据了解,OPPO（重庆）智能生态科技园由广东欧珀移动通信有限公司（"OPPO"）投资建设,项目位于渝北区前沿科技城石港大道中段,于2018年3月开工建设。项目总投资达70亿元,规划建筑用地面积约1 524亩,总建筑面
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发布时间：2024-04-01 - 摘要：<正>日前,由北海新绎游船有限公司和北海市万海船舶制造有限公司合作建设的高性能铝合金船艇建造项目,在北海新绎游船有限公司海运船厂举行启动仪式。据介绍,该项目具有良好的经济效益、社会效益和环境效益,对加快发展海洋型经济、推动经济社会发展具有重要意义。项目设计生产能力为4～24 m游艇及功能船舶1 000艘/年,年产值不低于2亿元,贡献税收1 000万以上。"该项目总投资5 000万元,建设期限为2019年6月～2020年12月。项目定位于打造铝合金船艇的建造、销售、靠泊、维保为一体的自主品牌,力争创造复合、开放、
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发布时间：2024-04-01 - 摘要：<正>即将在上海举行的"CHINA DIECASTING 2019中国压铸展"上,浙江万丰科技开发股份有限公司（下称"万丰科技"）将首次现场展示整条低压铸造生产线及方案,从原料到铸件产品,从熔炼、铝汤处理、铸造成形、喷涂、取件、切边、去毛刺、抛光打磨、热处理等一体化、全自动生产线解决方案,展示其在全线设备研发、软件开发、系统集成等方面的强大实力。万丰科技智能装备事业部总经理吴军先生表示:"工业4.0是行业发展潮流,压铸及铸造车间在这方面尤为迫切。今天,我们推出整条全自动化低压铸造生产线,为客户提供从原料到成品的智能自动化生产解决方案。10年前,我们主要为客户提供单一的低压或重力铸造设备;5年前,我们开始提供成套智能生产单元,这是市场变化与行业发展趋势,我们既顺应行业潮流也满
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发布时间：2024-04-01 - 摘要：Tribaloy T-800 shaft sleeves were produced by silica sol investment casting.After heat treatment,the shaft sleeves meet the requirements.During smelting and pouring process,some key points were paid attention such as the sequence of materials puting into the medium frequency induction furnace,melting temperature,liquid steel temperature-reduction process,pouring temperature.In addition,the riser was covered with thermal insulating agent and controlling the solidifying curve,keeping the castings cool slowly,so shaft sleeves with full Laves′phases were produced.关键词：Cobalt-Base Alloys;Tribaloy T-800;Investment Casting
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发布时间：2024-04-01 - 摘要：The casting defect distribution and macro-morphology of the directionally solidified IC10 superalloy turbine blades were described.In addition,the microscopic morphology and the formation mechanism of defects were analyzed,which could be related with the inadequate feeding during the last stage of solidification.Afterwards,the chemical composition in the vicinity of defect region was analyzed in order to understand the effect of Al,Hf on the thermodynamic and kinetic of feeding process.Finally,phase field simulation via MICRess software was carried out to predict the effectiveness of heat radiation on the solidification process at various cooling rate.The results reveal that with cooled at a lower rate,untransformed liquid tends to form connected channels in interdendritic region,which is in accordance with the morphology of defects observed experimentally.关键词：Directionally Solidified Superalloy;Casting Defects;Characterization Method
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发布时间：2024-04-01 - 摘要：DTA,stereo microscope,SEM and micro-area EDS were used to observe and analyze the shrinkage porosity in the gypsum mold jewelry castings.The results show that during the solidification process,the crystal grows in dendritic form and the shrinkage porosity generated in the dendrite gaps is caused by insufficient feeding of external liquid metal.Some parameters,such as alloy properties,casting structure,pouring system,mould temperature and pouring process,have significant impact on the dendritic growth and shrinkage porosity.To avoid shrinkage porosity defect in jewelry casting,alloy materials with suitable melting point and narrow solidification range should be selected preferentially,and jewelry structure and pouring system should be optimized,and castings with markedly different structures should not be poured at the same time,meanwhile,the mould temperature and pouring temperature should be controlled reasonably,and sufficient feeding force should be provided by centrifugal pressure casting or vacuum suction casting.关键词：Jewelry;Gypsum Mould;Investment Casting;Shrinkage Porosity;Technological Measures
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发布时间：2024-04-01 - 摘要：SiCp/2024 aluminum matrix composites with a volumetric fraction of 60% SiCp were prepared using a powder semi-solid thixoforming process.The effects of SiCp article morphology and heat treatment on the properties of the composites prepared were investigated.The results reveal that the composite reinforcement particles prepared by surface-shaped SiCp articles are uniformly dispersed in the aluminum matrix,and the relative density can reach 99.97%.After the stress relief annealing and T6 heat treatment,the composites present the desirable comprehensive performance,and the flexural strength and hardness of the composites are obviously improved,which is 47.5%and 57.7%higher than those of ones before heat treatment.The fracture of the composites exhibits a cleavage fracture of SiC as a whole,and the matrix exhibits tearing behavior.After SiC particle shaping and composite annealing as well as T6 heat treatment,the CTE of the composites is reduced to（4.85～8.51）×10-6℃-1 and（4.86～8.32）×10-6℃-1,respectively.The improved H-J model is better suitable for mixed reinforcement and bimodal particle size distribution.After SiC particle shaping and composite annealing as well as T6 heat treatment,the TC of the composites is significantly improved,reaching 195 W·m-1·K-1 and 206 W·m-1·K-1,respectively.关键词：Powder Semi-solid Thixoforming Process;SiCp/2024 Aluminum Matrix Composite;Particle Shaping;Heat Treatment;Thermo-physical Performance
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发布时间：2024-04-01 - 摘要：The lamellar-interpenetrated gradient SiC/Al-Si-Mg composites with 20% SiC content（in volume fraction）were prepared by directional freeze casting combined with squeeze infiltration process.The microstructure and element distribution in composites,interface between Al-Si-Mg and SiC were investigated by scanning electron microscope（SEM）,energy dispersive spectroscopy（EDS）and X-ray diffraction（XRD）.The results reveal that liquid Al-Si-Mg alloy is completely infiltrated in the lamellar SiC preform prepared by directional freeze casting process and the interface of Al-Si-Mg and SiC in composite is well bonded.The gradient lamellar structure of SiC preform is well preserved in the composites.The SiO2 film is generated on the surface of SiC particles after sintering at 1 300℃,and the MgAl2O4 phase is formed in the infiltration process,which improves the wettability and interface bonding between the matrix phase and the reinforced phase.关键词：Directional Freeze Casting;Squeeze Infiltration;Lamellar-interpenetrated Gradient SiC/Al-Si-Mg Composites;Microstructure;Interface
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发布时间：2024-04-01 - 摘要：The effects of Fe3Al reinforced particles and deformation technology on microstructures and mechanical properties of the Fe3Al/Cu composites fabricated by in-situ reaction were investigated by XRD,OM,SEM,TEM and tensile testing.The results show that with the increase of Fe3Al contents,the grain size is decreased.The nanoscale Fe3Al particles are uniformly distributed in Cu matrix.After cold rolling and annealing,obvious grain refinement and significant increment in strength are observed.After 90%cold-rolling reduction,the hardness and strength of 10% Fe3Al/Cu composite containing 10% Fe and Al elements reach 272 HV and 871 MPa,respectively.关键词：Composites;Fe3Al Second Phase;In-situ Reaction;Mechanical Properties
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发布时间：2024-04-01 - 摘要：AlTiVZr0.2B0.2 high entropy alloys were prepared by vacuum hot pressing sintering process at varied sintering temperatures.The microstructure and mechanical properties of the alloy prepared were investigated.The results show that AlTiVZr0.2B0.2 high entropy alloy mainly consists of the matrix phase with simple cubic structure and spherical precipitates of black TiB12 and white Al3Zr2.The densities of the alloys are lower than that of TC4 titanium alloy while the hardness and compressive strength are higher than that of one.Especially,the AlTiVZr0.2B0.2 alloy prepared at 1 100 ℃ presents the highest hardness（809.7 HV）,compressive strength（2 080 MPa）and specific strength（432.7×103 N·m/kg）,which is attributed to the precipitation of TiB12 and white Al3Zr2 in the microstructure of the alloys sintered at 1 100℃ with the highest dispersion degree and the most uniform distribution,so showing the desirable dispersion strengthening effect.关键词：High Entropy Alloy;Hot Pressing Sintering;Microstructure;Mechanical Properties
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发布时间：2024-04-01 - 摘要：Based on the first principles method,the formation energy,binding energy,adsorption energy and population number were calculated to understand effects of Ti and Al addition on the high temperature oxidation resistance of Nb/Nb5Si3 composites.The results reveal that the oxidation resistance of Nb/Nb5Si3 composites can be improved by doping Ti and Al elements,and the adsorption becomes more stable,especially the existence of Ti,which can preferentially react with O to form titanium dioxide,thus hindering the diffusion of O to the matrix to a certain extent.Therefore,the doping of Ti is superior to that of Al,which can improve the high temperature oxidation resistance of Nb/Nb5Si3 more effectively.关键词：First Principles;Oxidation Resistance;Nb/Nb5Si3;Adsorptive Energy
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发布时间：2024-04-01 - 摘要：The effects of different calcium content on corrosion resistance of ZA104 alloy in 3.5% NaCl solution were investigated by metallographic microscope,static weight loss corrosion test and electrochemical method.The results reveal that the static weight loss corrosion rate of ZA104 magnesium alloy in NaCl solution is decreased and then increased with the increase of calcium content.The self-corrosion potential of ZA104 alloy is increased with the addition of calcium.With 0.3% Ca addition,the polarization curve of the alloy shows that the self-corrosion current density is the lowest,and the corrosion resistance of ZA104+0.3 Ca alloy presents desirable.In addition,the addition of calcium is beneficial to refine the structure and improve the corrosion resistance of the alloy.关键词：Ca;ZA104 Magnesium Alloy;Corrosion Resistance;Polarization Curve
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发布时间：2024-04-01 - 摘要：The Al-5Fe,Al-5Fe-0.9Ce and Al-5Fe-5Ce alloys were heated to 800℃,900℃and 1 200℃to observe the iron enrichment morphology under different superheat conditions including furnace cooling,mold cooling and liquid quenching.The results show that with the degree of superheat of 127℃,the size of the iron-rich phase is refined remarkably.At degree of superheat of 127℃,the iron-rich phase is the finest in liquid quenching condition.关键词：Superheat;Cooling Rate;Al-5Fe Alloy;Iron-rich Phase;Microscopic Morphology
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发布时间：2024-04-01 - 摘要：6013 aluminium alloy sheets obtained by semi-continuous casting and extrusion were investigated,focusing on the effects of extrusion temperature and speed on the structure and properties,by optical microscopy,scanning electron microscopy,tensile and hardness testing.The results reveal that both extrusion temperature and extrusion speed have significant effects on the microstructure and mechanical properties of the 6013 aluminum alloy.Recrystallized structure is trend to be generated at higher extrusion temperature or speed.At a lower extrusion speed,the tensile strength of the alloy reaches its maximum at 500℃.The elongation and hardness of the alloy are decreased with the increase in temperature at various extrusion speed.Moreover,fractographic analysis reveals that the alloy with large and deep dimples accompanied with tearing edges observed in the fractography presents the higher plasticity.关键词：6013 Aluminum Alloy;Mechanical Properties;Extrusion Temperature;Extrusion Speed;Recrystallization
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发布时间：2024-04-01 - 摘要：The energy absorption of the 7075 alloy during low temperature impact was investigated at 0,-25℃,-50℃,-80 ℃,-120 ℃,respectively.It is found that with the decrease of temperature,the impact crack shape energy Eiof the 7075 alloy is gradually increased,while the impact crack instability expansion energy Eupof the 7075 alloy is gradually reduced,however,the total energy Eadd（Eaddis the sum of Eiand Eup）is relatively stable.The average strength energy Estunder high impact load is the main factor on the low temperature impact behavior of 7075 alloy,and the average strength energy Estunder high impact load is determined by the increase of the average impact load Faveand the change of the metastable extended displacement dstjointly.关键词：7075 Alloy;Low Temperature Impact;Impact Load;Metastable Extended Displacement
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发布时间：2024-04-01 - 摘要：The coatings can reduce casting defects such as sand sticking,inclusions,sand holes,sulfur-increment and improve surface quality of castings as well as reducing cleaning workload and production costs,improving production efficiency.Magnesia powder was used as aggregate,sodium bentonite and sodium carboxymethyl cellulose（CMC）as suspension agent,sodium silicate and starch as binder,and water as carrier.With different size of refractory aggregate,the number of magnesia powder was increased from 200 mesh to 340 mesh.Coatings were designed to test the properties of coatings,and the effect of size of refractory aggregate on the properties of coatings was analyzed.关键词：Magnesia Powder;Granularity;Magnesia Powder Coating Performance
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发布时间：2024-04-01 - 摘要：The effects of B addition on microstructure and properties of the ZM5 magnesium alloy were investigated.The results show that the B element presents the satisfied grain refinement effects.With increasing in B addition,grain size in the alloy is decreased gradually.With 0.03% B addition,the average grain size of ZM5 magnesium alloy is only 76μm,which is decreased by 72.2%compared with that of the unrefined ones,which is attributed to the generation of AlB2 compound with Al and B to act as heterogeneous nuclei to refine grain size in the alloy.With increasing in B additions,the hardness of ZM5 magnesium alloy is further increased.With 0.03% B addition,the hardness of ZM5 magnesium alloy is increased by 23.2%compared with that of the unrefined ones.关键词：B;ZM5 Magnesium Alloy;Microstructure;Hardness
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发布时间：2024-04-01 - 摘要：Φ16 mm Cu-3.5 Ag alloy rods were prepared by horizontal Ohno continuous casting process,and the influence of continuous casting speed on the microstructure,electrical conductivity and mechanical properties of Cu-3.5 Ag alloy were investigated systematically.The results show that the continuous casting speed has a significant effect on the microstructure and properties of Cu-3.5 Ag alloy.The microstructure perpendicular to the continuous casting direction is dominated by the staggered " woven fabric" dendritic morphology,and as the continuous casting speed increases,the dendrites are gradually refined.The microstructure parallel to the continuous casting direction is regularly arranged as the "fishbone",and as the continuous casting speed increases,the "fishbone" dendrites are gradually increased.In addition,the non-equilibrium eutectic phase is mainly distributed in the dentrite arm spacing.As the speed of continuous casting increase,the electrical conductivity of the alloy is increased from48.082 MS/m to 50.054 MS/m,and the hardness is increased from 60.3 HBW to 69.2 HBW.In test range,when the continuous casting speed is 50 mm/min,the strength and electrical conductivity of Cu-3.5 Ag alloy are acceptable,and the overall performance is desirable.关键词：Horizontal Ohno Continuous Casting;Cu-3.5Ag Alloy;Continuous Casting Speed;Electrical Conductivity;Microstructure
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发布时间：2024-04-01
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