最新刊期
卷 39 ， 期 2 ， 2019
- 摘要：The mechanical properties of cast Be-37.6Al-0.4Sc alloy were characterized by nano-indentation and tensile tests,and effects of Sc-alloying on the microstructure and fracture behaviors of the alloy were investigated via tensile fractography and optical metallography.With Sc alloying,the microstructure of the Be-Al alloy is converted from coarse columnar dendritics to uniform and fine equiaxed grain,which are responsible for improving strength and decreasing plasticity.The Sc-containing secondary phases presents the highest elastic modulus of 321.48 MPa,the highest hardness of 9.83 GPa and the lowest plasticity index of 0.803 compared with those of the matrix alloy.The secondary phases locating at the Be/Al interfaces is not acted as pre-existing micro-crack sources during the deformation,whereas the highly-faceted secondary phases within Be grains induced the formation of micro-cracks and resulted in the decrease of elongation.The failure mode of Be-37.6Al-0.4Sc alloy are characterized by brittle cleavage failure of Be regions and ductile dimple failure of Al regions compared with the Be-Al alloy.关键词：Be-Al Alloy;Secondary Phase;Nano-indentation;Fractography
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发布时间：2023-12-18 - 摘要：The effects of different magnetic field excitation currents on the solidification microstructure and mechanical properties of ZL205A alloy were investigated by using downward traveling wave magnetic field,and the evolution law ofθphase was analyzed.The results show that the traveling wave magnetic field can refine the alloy structure to form fine near-equiaxed crystal structure,and improve the tensile strength and elongation of ZL205A alloy.Meanwhile,the excitation current of the magnetic field has a direct effect on the refinement effect of solidification structure.With the current frequency of 50 Hz,the desirable excitation current for ZL205A alloy is in range of 10～20 A.In addition,with the increase of the excitation current,theθphase appears to be paramagnetic in the magnetic field.As the magnetic field increase,the nucleation undercooling degree is increased,so the nucleation rate is increased andθphase is broken down.When the excitation current is less than 10 A,the electromagnetic force generated by the magnetic field has a great influence on the size of theθphase.When the magnetic current is 20 A,the melt viscosity is increased as a result of the magnetic field Lorentz force,which can prevent theθphase from further refinement.关键词：Downward Travelling Magnetic Field;ZL205A Alloy;Microstructure;θ Phase;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The casting-heat treatment integration process was put forward to treat Al-Si-Cu-Mg alloy.In the new process,the castings were put into heat-treatment furnace immediately after stripping the die.By utilizing the waste heat of the casting process,casting and solution treatment were conducted consecutively.In solution treatment process,more then half of man-hour and about 35% of energy consumption of traditional T6 heat treatment process can be cut in the integration process.After heat treatment in T6 process and integration process,Al-SiCu-Mg alloys have comparable mechanical performance,where the tensile strength and elongation reach 310 MPa and 2.3%,respectively.关键词：Heat Treatment;Casting-Heat Treatment Integration Process;Al-Si-Cu-Mg Alloy;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The effects of electroslag remelting with different low frequencies on the quality of NO8367 austenitic stainless steel ingots were investigated.The results show that the properties of the ingots after remelting are significantly improved,especially in the samples prepared at 7.5 Hz,where the number of inclusions is the least,and the mechanical properties are desirable with tough fracture morphology.关键词：NO8367Austenitic Stainless Steel;Low Frequency;Electroslag Remelting;Inclusions
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发布时间：2023-12-18 - 摘要：The surface modification was used on FSC（FeSi7Cr3）magnetic powder with the coupling agent KH560 through the ball milling process.The microstructure and thermal analysis properties of the surface modification layer were analyzed by scanning electron microscopy（SEM）and thermogravimetric analysis（TG）.The vector network analyzer was adopted to measure the electromagnetic parameters of the microwave absorbing materials.The results show that the shape of the magnetic powder particle is changed from spherical to flat after ball milling treatment.TG results show that the sample after surface treatment still has good oxidation resistance after oxidation for 4 hat 900℃.The electromagnetic parameter results show that the dielectric parameters of the sample after high temperature oxidation are decreased,which is conducive to improving the dielectric matching of microwave absorbing materials.The high-temperature oxidation results show that the surface modification of FSC magnetic powder with coupling agent KH560 can improve the high-temperature resistance of the microwave absorbing material.The surface-modified FSC magnetic powder still maintain good microwave absorbing properties after high temperature treatment.At the oxidation temperature of 700～900℃,the reflection loss peak is shifted from 4 GHz to high frequency near 6 GHz,and the reflection loss performance is kept at approximately 15 dB.The surface-modified absorbing material shows the satisfied oxidation resistance and microwave absorbing characteristics.关键词：Heat Resistant;Coupling Agent;Surface Modification;Magnetic Powder;Absorbing Material
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发布时间：2023-12-18 - 摘要：<正>印度计划建造该国首座千兆瓦时级别的电动汽车锂离子电池工厂。该项目将成为"印度制造"倡议的一部分,能够提高电动汽车重要部件的国内生产效率。近日,印度LIBCOIN财团、马格尼斯能源技术有限公司、印度巴拉特重型电器有限公司与印度政府、重工业部门和公共企业部门达成协议,将要建立印度首座锂离子电池
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发布时间：2023-12-18 - 摘要：<正>近日,据日本经济新闻报道,新日本钢铁公司和神户制钢所分别开发出汽车用钛合金,并已开始着手开展相关业务。新日本钢铁公司的目标是在排气消声器和发动机阀门等配件上使用钛合金。神户制钢所在钛合金线材的量产化方面取得了成功,将于近期开始向汽车厂商提供样品。此外,新日本钢铁公司和神户制钢所还在联合开发钛合金低成本制造技术。如果该技术能在汽车这一材料需求
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发布时间：2023-12-18 - 摘要：<正>德国乌尔姆亥姆霍兹研究所和卡尔斯鲁厄理工学院正在共同开发基于镁的储能技术。镁电池是欧盟"展望2020"科研计划下的项目（E-MAGIC）,欧盟为此已投资超过650万欧元,汇集了欧洲10个科研机构的专业技术,未来该项目如取得成功,将有望替代现有的锂离子电池。镁电池与传统锂离子电池相比具有更多优点。据乌尔姆亥姆霍兹研究所副主任、该项目负责人马克西米利·费希特内教授
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发布时间：2023-12-18 - 摘要：Based on octree data structure,an algorithm for adaptive subdivision of finite differential meshes was developed.The algorithm uses the STL file model as the root node for spatial segmentation,and generates an unbalanced tree by recursively calculating and setting critical stop condition,so complex shape parts of complex models can be divided adaptively.The corresponding program was developed to calculate and analyze the geometric model file,and finally proved it could produce a high quality octree non-uniform grid.关键词：Octree;Adaptive Meshing;STL File;Finite Differential Method
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发布时间：2023-12-18 - 摘要：According to the structural characteristics of the shell seat,the die casting die and die-casting process were designed.The filling and solidification process of shell seat was simulated by the ProCAST software.The reasonable die-casting parameters were presented as follows:pouring temperature of 590 ℃,injection velocity of 3.4 m/s,mold preheating temperature of 165℃.The die-casting experiments with optimized die casting parameters were carried out,and qualified shell seat was manufactured sucessfully.The metallographic structure of the shell seat was observed,which verified that the quality was qualified.关键词：Shell Seat;Numerical Simulation;Filling Solidification;Processing Optimization
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发布时间：2023-12-18 - 摘要：Aiming at two kinds of extremely similar die casting shell,two kinds of die structure and reasonable pushing mechanisms were analyzed.For the thin-walled large cladding shell castings,the problems that the parts were broken easily by the push rod was solved successfully by using the two-stage ejection mechanism when the cavity was located at the moving mold.Through using auxiliary gate,the problem of insufficient feeding for side gate was eliminated.The structure of two-stage ejection mechanism has the features of simple,practical,and reliably.关键词：Two-stage Ejection;Side Gate;Auxiliary Gate;Shell Casting
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发布时间：2023-12-18 - 摘要：The shrinkage holes（porosities）in an aluminum alloy cylinder block with a large wall thickness were investigated.A series of countermeasures were considered from the formation mechanism of shrinkage holes in the aluminum alloy die-casting parts and the actual shrinkage conditions.First,through increasing the casting pressure from 65 MPa to 90 MPa and increasing thickness of the cake from 25 mm to 30 mm,the effect presents unsatisfactory.Then,the cooling condition of the mold cooling system was modified,and the spraying time of the release agent was increased,however,the effect could be neglected.Finally,combining with the principle of liquid aluminum solidification feeding,two pins in the region of the shrinkage holes were added with rationally adjusting the squeezing parameters,the shrinkage rate was reduced from 5% to 0.2%,achieving the desirable effect.关键词：Cylinder Block;Shrinkage Holes;Cooling System;Feeding;Squeezing Pin
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发布时间：2023-12-18 - 摘要：The effects of different forming temperatures and different heat treatment processes on squeezing casting bimetal track plate were investigated by numerical simulation.The results reveal that the track plate is first solidified ahead at the contact position of the steel skeleton and mould,which is also the stress concentration position.The shrinkage defects,such as porosity,may appear in the thick and large position of the final solidification.The steel and aluminum composite forming of the bimetal track plate can be realized by squeezing casting with absence of defects such as shrinkage and crack.The microstructure of the squeezing castings presents typically near spherical structure with the uniform and fine distribution.There exist some fine grain regions and mixed crystal areas at the interface of the steel and aluminum.The grain boundary of the alloy is smooth after heat treatment and the intergranular phase disappears.After heat treatment,the interface of steel and aluminum is separated slightly with about 2～6μm.The Brinell hardness of high strength aluminum alloy after first stage solid solution reaches 165 HB,and it reaches 180 HB after the two-stage solid solution treatment.关键词：Bimetal;Track Plate;Squeezing Casting
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发布时间：2023-12-18 - 摘要：The casting defects such as looseness,segregation,crack,flux inclusion and porosity in anti-gravity pressure casting magnesium alloy shells were analyzed.The corresponding countermeasures were put forward.Through strictly controlling casting process,molding quality and metal liquid quality,a reasonable process plan was designed to reduce casting defects,meeting Class I casting requirements.关键词：Anti-Gravity Pressure Casting;Magnesium Alloy Shell;Casting Defects
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发布时间：2023-12-18 - 摘要：<正>为加强锂离子电池行业管理,引导产业转型升级,大力培育战略性新兴产业,推动锂离子电池产业健康发展,工信部对《锂离子电池行业规范条件》和《锂离子电池行业规范公告管理暂行办法》进行了修订,修订的锂电池行业规范条件和管理暂行办法自2019年2月15日起施行。《规范条件》指出,在国家法律法规、规章及规划确定或省级以上人民政府批准的自然保护区、饮用水水源保护区、
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发布时间：2023-12-18 - 摘要：<正>2019年1月2日,湖北省航特汽车底盘轻量化项目建设现场,机加车间正在进行钢构主体施工,铸造车间主体工程已完工项目负责人介绍,价值1亿元的生产设备已经从国外订购,两台低压铸造机正从德国转运至深圳海关。航特装备制造股份有限公司是一家以节能减排净化技术开发、产品制造、轻合金材料及成型技术开发、产品制造及航空产品销售与运营、液压制动器设计与制造为业务的创新型高新技术企业。
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发布时间：2023-12-18 - 摘要：<正>近日,湖北十堰市张湾区举行2019年第一季度重点项目集中开工仪式。此次开工项目48个,总投资200亿元,其中包括多个压铸件及汽车零部件建设项目。其中,浙江正成汽车零部件新工厂项目,投资6 000万元,占地18亩,厂房1.1万m2,主要从事铝压铸件研发、生产和销售。东风（十堰）有色铸件有限公司2 500t高性能压铸自
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发布时间：2023-12-18 - 摘要：<正>近日,从陕西省工信厅获悉,陕西省新材料产业近年来快速发展,其新品研发在诸多关键领域实现快速突破,极大地推进了陕西省原材料工业的转型升级,也为陕西省工业高质量发展提供了材料保障。截至目前,陕西省新材料产业年产值占原材料工业年产值比重超过25%。陕西省目前在超导材料、特种轻质合金材料、核电装备材料、金属3D打印材料等关键领域的产品成功实现产业化应用,一
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发布时间：2023-12-18 - 摘要：Based on the numerical simulation analysis,the shrinkage porosities in ZG0Cr17Ni4Cu3Nb alloy parts for tail lap part of aircraft engine,which was manufactured by investment casting,were investigated by the orthogonal experiment method and trial.The effects of the main process parameters,such as pouring temperature,casting speed and mold temperature,on probability of shrinkage volume were expounded.And the influence of various process parameters on shrinkage porosities was described.The results reveal that the pouring temperature has the largest effect and the second is the mold temperature.Combined with numerical simulation,the design of the gating system was also optimized.The reliability of the simulation results was verified through trial-production,and the qualified castings were produced sucessfully.The optimized process parameters are presented as follow:the symmetry arrangement of the inner gate on both sides,pouring temperature of 1 560℃,pouring rate of 320 mm·s-1 and mold temperature of 920 ℃.关键词：Stainless Steel;Aero-Engine;Investment Casting;Shrinkage Porosities;Optimized Process
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发布时间：2023-12-18 - 摘要：In view of the structure features that narrow slots and thin blades appearing alternately,and difficult to forming,the process of investment casting was made from trial-and-error experiments.In making wax mould process,the mould was composed of whole ceramic core and separated wax pattern.During smelting,needle blanket was used to parcel the thin blades area for insulation,and heat the shell at high temperature and pour also at high temperature and tilted.Through this process,the requirement of skill level and labor strength of works could be decreased.Meanwhile,the production efficiency could be improved with stable quality.关键词：Investment Casting;Narrow Slot;Thin Blade;Ceramic Core
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发布时间：2023-12-18 - 摘要：The copper cladding aluminum composite rod with 12 mm in outer diameter and 8 mm in inner diameter was prepared by continuous casting with nitrogen pressure and core-filling.The composite wire with 0.6 mm in diameter was manufactured by multi-passes drawing without annealing.Copper cladding aluminum wire prepared has smooth surface with absence of dent and cracks as well as other defects,meanwhile,the ratio of copper and aluminum keeps stable at different stages of processing.The drawn composite wires were annealed at different temperatures for 1 h.The results show that the satisfied comprehensive performances can be obtained at 450 ℃,where tensile strength,elongation and direct current resistivity reach 208.43 MPa,13.44% and 2.454×10-8Ω·m,respectively,meeting the requirement of electronic industry standard.关键词：Copper Cladding Aluminum;Continuous Casting;Composite Wires;Annealing
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发布时间：2023-12-18 - 摘要：A new type of Cu-Sn-Ti-B alloy wire was designed by horizontal continuous casting-cold rolling and drawing.The effects of cold deformation and isothermal annealing on microstructure and properties of the alloy prepared were investigated by means of optical microscopy,scanning electron microscopy,hardness testing,electrical conductivity and tensile testing.The results show that the microstructure of the as-cast alloy is large bulkyαmatrix phase with a length of millimeters,after the cold working,the distortion of the crystal grains is obviously elongated.When the lead speed is 230 mm·min-1,the as-cast alloy rod presents the desirable mechanical properties,where tensile strength and elongation reach 186 MPa and 44%,respectively.In addition,the alloy wire with φ3 mm is subjected to isothermal annealing at 400～500 ℃for 100 min,resulting in recrystallization in the alloy and refinement of the grains.After isothermal annealing for the alloy at different temperatures,it is found that a certain precipitation behavior can be observed in solid solution of the alloy.Meanwhile,after annealing at 400～500 ℃for 100 min,the alloy wire has a maximum electrical conductivity of 48.314 MS/m.The Cu-Sn-Ti-B alloy wire with a diameter of 1 mm has excellent performance with strength of 550 MPa and conductivity of 47.56 MS/m,which was drawn by the alloy wire with φ3 mm annealed at 500 ℃ for 100 min.关键词：Cu-Sn-Ti-B Alloy;Tensile Strength;Electrical Conductivity;Microstructure
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发布时间：2023-12-18 - 摘要：Based on the deep analysis of the characteristics of lost foam casting and Flow-3D,the temperature,pressure and negative pressure mathematical models affecting the heat transfer coefficient were reconstructed on the basis of the deficiency of the simulation model.Fortran language was used to write the software code and visual studio 2008 development environment compiled link to generate executable programs.The developed 3D model was used to simulate the lost foam casting.The simulated results were compared with the experimental ones.The results show that the developed simulation model of the lost foam casting based on Flow-3 Dis feasible and instructive to practical production.关键词：Lost Foam Casting;FLOW-3D;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Striped slag is often appeared in the spigot position of centrifugal ductile iron pipes.The average thickness of slag layer is about 5～10 mm with black and dense structure,resulting in poor appearance and worse internal performance.The analysis reveals that the Si content in the stripped slag reaches 65.15%,and the "silicon rich structure" is formed by the accumulation of iron melt inoculant in the socket site without melting and diffusion.The stripped slag is mainly attributed to the advanced flow of Fe liquid.According to the analysis,through refining molten iron and strictly controlling the advanced flow of molten iron as well as pouring at high temperature,keeping uniform flow of the liquid Fe in the flow slot and matching with inoculants,stripped salg can be eliminated effectively.关键词：Centrifugal Ductile Iron Pipe;Striped Slag Defect in the Spigot;Advanced Flow of Molten Iron
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发布时间：2023-12-18 - 摘要：Mg3Sb2/Mg and（Mg3Sb2+AlSb）/Mg composites with a varied volume fraction of Mg3Sb2 and Mg and（Mg3Sb2+AlSb）were prepared by in-situ reaction.The phase and morphology of the composites were analyzed by XRD and SEM.The hardness and mechanical properties of the composites were tested by microhardness tester and CTM universal testing machine.The electrochemical corrosion performance of the composites in 3.5% NaCl solution was measured by electrochemical workstation.The results show that the in-situ reaction method can fabricate Mg3Sb2/Mg and（Mg3Sb2+AlSb）/Mg composites with different volume fractions.In addition,the hardness,yield strength and tensile strength of Mg3Sb2/Mg composites can be improved significantly with the addition of Al.The corrosion potential of Mg-15.4 Sb-5 Al composite is-1.38 V,presenting the desirable corrosion resistance.The corrosion resistance of（Mg3Sb2+AlSb）/Mg composites is superior to that of Mg3Sb2/Mg composites.关键词：In-situ Synthesis;Composites;Intermetallic Compound;Mechanical Properties;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：Mg/Al composite plates were fabricated by liquid-solid cast rolling technology,which were annealed treatment subsequently.The effects of annealing temperature on the relationship between microstructure and mechanical properties of the composite plates were analyzed.The results reveal that the interfacial transition zone of Mg/Al composite plates is divided into three regions,region Ⅰ adjacent to AZ31B forming Mg transition region(δ-Mg and Mg17Al12),region Ⅱ close to A356 forming Al transition region（α-Al and Al3Mg2）,and the diffusion interfacial middle region Ⅲ (Mg17Al12、Mg2Si and Al3Mg2).The width of Al transition region is more than that of Mg transition zone.The microhardness of the interfacial transition zone is obviously higher than those of bilateral alloys.When the annealing temperature is or lower than 250 ℃,absence of new intermetallic compounds can be observed in the interfacial transition zone.When annealing temperature is higher than 250℃,thickness of the interfacial transition zone is grown in form of exponent with the increase of annealing temperature.After annealing at 250 ℃ for 180 min,the tensile strength,yield strength and elongation of the composite plates reach 188 MPa,148 MPa and 10.1%,respectively,and the comprehensive mechanical properties present desirable.关键词：Liquid-solid Cast Rolling;Annealing Temperature;Interfacial Transition Zone;Intermetallic Compounds
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发布时间：2023-12-18 - 摘要：Graphene/aluminium matrix composites were prepared by filling graphene and graphene/aluminium powder into aluminium plate（one-step and two-step）with FSP,respectively.The influences of FSP preparation method on the dispersion,structural damage of graphene in aluminium matrix and the mechanical properties of the composites were investigated by OM,SEM,EDS and tensile testing.The results reveal that the graphene dispersion is more uniform,and the structural damage is less for the two-step FSP preparation method.The tensile strength of the composite prepared by two-step FSP reaches 115 MPa,which is 15% higher than that of the onestep FSP.关键词：FSP Preparation Method;Graphene/Aluminum Matrix Composites;Dispersion;Structural Damage
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发布时间：2023-12-18 - 摘要：The laser-MIG composite welding was used to weld Q960 steel/6061 aluminum dissimilar metal,and the microstructure,phase composition and mechanical properties of the composite welded joint before and after adding Cu were analyzed comparatively,and the fracture morphology was observed.The results reveal that the weld joint remains the typical melt brazing characteristics after Cu addition,and the interface layer of the IZ region presents obvious change,where the thickness of the interface layer is decreased from 16μm before adding Cu to 6μm after adding Cu,and the needle like Fe4Al13 phase and the tongue Fe2Al5 phase in the interface layer are transformed into fine block Al13（Fe,Cu）4 and tongue Al5（Fe,Cu）2,and microcracks in the interface layer disappear.The maximum hardness of the steel/aluminum composite welded joint after adding Cu still occurrs in the interface layer,however the maximum hardness is reduced significantly,which is mainly related to the formation of Al13（Fe,Cu）4 and Al5（Fe,Cu）2 intermetallic compound in the interface layer.After adding Cu,the tensile strength and elongation of welded joints are increased by 110.5% and 183.3%,respectively,compared with those of ones before Cu addition,while the fracture locations are all located at the steel/aluminum interface region.关键词：Steel/Aluminum;Laser-MIG Compound Welding;Cu;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：The effects of cooling rate on the microstructure and mechanical properties of the as-cast Fe81（CoCrNiAl）4.75 high entropy alloy were investigated by SEM,EDS,XRD and tensile testing.The results show that the alloy undergoes martensite transformation at different cooling rates,and the volume fraction of martensite is increasesd with the decrease of cooling rate.The structure of the alloy is a single BCC phase.The mechanical properties of the alloy is changed with the decrease of the cooling rate,presenting the tendency of decrease firstly and then increase.The slip zone in the deformation zone is denser with the decrease of the cooling rate and the plastic deformation ability is enhanced.关键词：High Entropy Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The CuCrFeNiMn（S1）,CuCr2Fe2Ni2Mn2（S2）and Cu2CrFe2NiMn2（S3） high entropy alloys were prepared by arc melting process.The microstructure and corrosion resistance of the alloys prepared were investigated.The results show that the S1 and S3 alloys are composed of simple face centered cubic solid solution and body centerd cubic solid solution（FCC1+FCC2+BCC）,while the S2 alloy consists of single face centered cubic solid solution（FCC1+FCC2）.In 1 mol/L NaOH solution,the average corrosion rates of S1,S2,and S3 reach 0.078,0.04 and 0.119 mm/a in immersion testing,respectively,and the average corrosion rate of S1,S2,and S3 reach 7.2×10-7,2.8×10-7 and 3.4×10-6 mm/a in polarization corrosion testing,respectively.The S2 alloy shows an excellent alkali-resistance because of simple FCC solid solution and high content of Cr and Ni.关键词：High Entropy Alloy;Microstructure;Immersion Corrosion;Polarization Corrosion
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发布时间：2023-12-18 - 摘要：Experiments of removing non-metallic inclusions from commercial pure aluminum were conducted with a laboratory-scale apparatus by electroslag refining.The results show that the removal efficiency of inclusions by relectroslag refining is increased with the decrease of remelting rate.Under the remelting rate of 108 g·min-1,the removal efficiency can reach 97.6%.The reaction of the molten slag to capture inclusions accounts for the removal of inclusions in the refining process.It is explained thermodynamically by the Gibbs energy calculation that inclusions can transfer spontaneously from the aluminum melt to the molten slag.关键词：Inclusions;Aluminum;Electroslag Refining;Purification
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发布时间：2023-12-18 - 摘要：The dimensional deformation of large aluminum alloy frame during heat treatment was investigated.The experimental results reveal that the heat treatment deformation cann’t be completely eliminated by welding tendons.After quenching,there still exists deformation and the maximum deformation is 12.4 mm.After solid solution treatment,the frame structure castings are corrected by combining artificial with mechanical correction which can control effectively the deformation size within the effective range and meet the design requirements.The frame castings were added with reinforcing ribs and formed as a whole.The maximum deformation is 2～5 mm,obtaining the satisfied effects.关键词：Aluminum Alloy;Frame;Heat Treatment
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发布时间：2023-12-18 - 摘要：In order to solve the problems of poor corrosion resistance of high rare earth magnesium alloy,the surface treatment of magnesium alloy was performed by micro-arc oxidation to improve its corrosion resistance.For the micro-arc oxidation process adopted,based on analysis,the step-down method was used to control the process parameters,and the orthogonal test of each parameter of the electrolyte was analyzed.The ratio of the corrosion area obtained by the neutral salt sprayed testing and the thickness of the film observed by the metallographic phase were used as indicators to obtain the optimized electrolyte parameters.The thickness,phase composition and surface morphology of each group in the orthogonal experiment were analyzed by OM,XRD and SEM.The results reveal that when the voltages of each stage are 550 V,500 Vand 450 V,respectively（using the voltage control system under the step-down method）,with the negative voltage of 250 V,the duty ratio of 20% and the oxidation time of 50 min,the optimized electrolyte parameters can be obtained by range analysis:sodium silicate of 20 g/L,sodium tetraborate of 40 g/L,NaOH of 20 g/L,triethanolamine of 15 ml/L,nickel acetate of 0.12 g/L,a complexing agent（sodium citrate）of 15 g/L,where odium silicate presents the most importance.The film analysis by XRD and ED reveals that the film is mainly composed of the spinel phase Mg2SiO4,cubic structure of MgO,MgSiO3,MgCO3 and Ni2O3 as well as a small amount of Na,Gd and other elements.关键词：High Rare Earth Magnesium Alloys;Micro-arcoxidation;Orthogonal Experiment;Electrolyte Parameter;Corrosion
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发布时间：2023-12-18 - 摘要：The smelting process such as refining,modification and grain refinement of Al-6Si-3.5Cu-0.3Mg alloy for engine cylinder head was investigated.The results show that the Al-6Si-3.5Cu-0.3Mg alloy can achieve the satisfied refining effect by rotary injection refining process,and the holding time should be controlled within 1.5 has much as possible.Al-10Sr master alloy was used as a modifier,and when the amount of Sr added was 0.06%,better modification effect could be obtained.The grain refining treatment was carried out by using Al-5Ti-1B master alloy,and the addition of 3%,had better refining effect.关键词：Engine Cylinder Head;Refining;Modification;Grain Refinement
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发布时间：2023-12-18 - 摘要：Hot compression tests of equal channel angular pressed Mg-4Zn alloy were conducted on a Gleeble-3800 thermal-mechanical simulator at 200～350℃and 0.001～1 s-1.The deformation activation energy（Q）was calculated using a hyperbolic sine constitutive equation.The results show that Qis increased with strain increase.At the beginning of deformation,the rate controlling process is characterized by lattice self-diffusion controlled.At the late stage of deformation,the rate controlling mechanism is characterized by the cross-slip of dislocations.Based on the dynamic material model,the processing maps of Mg-4Zn alloy were established.The areas of the instability domains are decreased with increasing in strain since the initiation of non-basal slips and cross-slip enhancing the dynamic recrystallization process.Workability domain occurs at 260～350 ℃ and 0.01～0.1 s-1.关键词：Rate Controlling Mechanism;Workability;Processing Map;Equal Channel Angular Pressing;Magnesium Alloy
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发布时间：2023-12-18 - 摘要：The finite element software of Simufact was used to analyze the extrusion process of tin bronze connecting rod bushing.The processing parameters,such as punch extrusion speed,the punch radius,the punch working belt length and the extrusion temperature,were selected as the test factors,and the damage value of connecting rod bushing after extrusion was used as the evaluation index.Orthogonal testing was designed and analyzed,meanwhile Taguchi method was adopted to optimize the extrusion parameters.And the optimized parameters are presented as follows:the punch extrusion speed of 5 mm/s,the punch radius of 3 mm,the punch working belt length of 7 mm,and the extrusion temperature of 600 ℃.关键词：Simufact;Tin Bronze Connecting Rod Bushing;Extrusion;Taguchi Method;Damage Value
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发布时间：2023-12-18 - 摘要：Cu-25Zn-6Al-3Fe and Cu-25Zn-6Al-3Fe-4Mn alloy samples were prepared by medium frequency induction furnace smelting and graphite mould casting.The hardness and tribological properties of the two alloys were tested,respectively,and structure of the alloys was characterized by OM,XRD,SEM and EDS.The results reveal that both two kinds of alloy are composed of the CuZn matrix and the second phase.The addition of manganese does’ t change the type of the main strengthening phase and the self-lubricating phase of the alloy,and component testing confirms that the second phase of the two alloys belongs to iron-enrichment phase.The manganese element in the Cu-25Zn-6Al-3Fe-4Mn alloy exists in the matrix and iron-rich phase in form of solute atoms and has the highest concentration in the iron-enrichment phase.The addition of manganese can change the morphology of the second phase particles,and refine the size of the second phase,increasing the dispersion of the particles and improving the hardness of the matrix and the second phase by solid solution strengthening.As a result,the hardness of Cu-25Zn-6Al-3Fe-4Mn alloy reaches 251（HV）,and the friction coefficient and the wear rate reach 0.319 and 5 mg,respectively,and the tribological properties are superior to those of the Cu-25Zn-6Al-3Fe.关键词：High-Strength Brass;Mn Element;Hardness;Tribological Properties
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发布时间：2023-12-18
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