最新刊期
卷 34 ， 期 5 ， 2014
- 摘要：Effects of pulsed magnetic field with different excitation current and magnetic field frequency on structure and properties of Al-12.5Mg-6.7Si Alloy were investigated by scanning electron microscope（SEM）and hardness testing.The results show that with the increase of excitation current and magnetic flux density,primary Mg2Si and eutectic Mg2Si are fined greatly.Comparing with those in gravity field, the primary Mg2Si phase size is decreased by 36%and the hardness is improved slightly.However,primary Mg2Si is coarsened significantly with magnetic field frequency more than 2Hz,and the morphology of eutectic Mg2Si is transformed into needle from dot-like structure,resulting in the decrease of hardness.The pulsed magnetic field with excitation current of 1518Aand magnetic field frequency of 1 2Hz can improve remarkably the microstructures and mechanical properties of the Al-12.5Mg-6.7Si alloy.
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发布时间：2023-12-18 - 摘要：Effects of Gd addition on microstructure and mechanical properties of Mg-6Al-1.2Y-0.9Nd alloy were investigated by optical microscopy（OM）,scanning electronic microscopy（SEM）,tensile tests and XRD（X-ray diffraction）analysis.The results reveal that the refinement of microstructure in the alloy can not be observed,and the grain size is increased with keeping in a small size range.With 3.6% Gd addition,the tensile strength of the alloy at room and high temperature reaches up to the maximum value.The mechanical properties of Mg-6Al-1.2Y-0.9Nd alloy is slightly improved at 20175℃,and the mechanical properties are improved apparently at 200℃.However,the excessive addition of rare elements may weaken the strengthening effect on Mg-6Al alloy.关键词：Rare Earth;Magnesium Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Zn-Al alloy was fabricated under a transverse direct current steady-state magnetic field by using horizontal Bridgman directional solidification equipment.Effects of magnetic field on the microstructure and electrochemical properties of Zn-Al alloy were investigated through structure analysis,second dendrite arm spacing（SDAS）measurement and electrochemical property testing.The results show that the SDAS is decreased gradually and the microstructure is refined with the increase of the solidification rate. The SDAS reaches up to the minimum value of 24.294μm,and corrosion current density is 11.62 μA/cm2 in 3.5% NaCl solution at the current intensity of 80Aand solidification rate of 1K·s-1.关键词：Zn-Al Alloy;Directional Solidification;Magnetic Field;Electrochemical Behavior
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发布时间：2023-12-18 - 摘要：Effects of Si and RE on the hot-dip aluminizing HK40heat-resistant steel were investigated.By means of optical microscope,scanning electron microscope and energy spectrum analysis,the microstructure and element distribution of coating were analyzed.The phase constitute of coating was investigated by X-ray diffraction,and the hardness testing was carried out at different zone from steel base to coating.The results show that the surface thickness of coating is decreased and exhibits more smoothly, meanwhile,the coating and the matrix are characterized by metallurgical bonding with the addition of Si and RE.More FeAl3and Fe2Al5phases appear in coating,and the micro-hardness of transient layer is improved largely.关键词：HK40Heat-Resistant Steel;Hot-Dip Aluminizing;Structure;Si;RE
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发布时间：2023-12-18 - 摘要：Effects of retrogression and reaging（RRA）treatment on microstructure and mechanical properties of underaged spray forming 7075aluminum alloy were investigated by transmission electron microscope（TEM）and tensile testing,and compared with those of alloys under peak aging and conventional RRA treatment.The results show that underaging at 120℃for 12has preaging treatment is more beneficial for the re-dissolution of precipitates in matrix than peak aging（T6,120 ℃×24h）in retrogression treatment.By retrogression treatment,the precipitates on the grain boundary are disconnected completely.After reaging treatment,fine and dispersed precipitates can be observed in the grain.And the tensile strength and yield strength of the alloy reach 776MPa and 723MPa,respectively,which are higher than those in T6or conventional RRA treatment.关键词：Spray Forming;7075Aluminum Alloy;Underage;Retrogression and Reaging;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of extrusion temperature on microstructure,mechanical properties and biodegradation of Mg-2.2Zn-1Mn-0.5Ca alloy were investigated.The results show that complete crystallization occurs at 280℃,and the crystallized grains are coarsened obviously with the increase of extrusion temperature, accompanied with the decrease of mechanical property.Meanwhile,the dislocation density is increased with increasing in extrusion temperature,which is responsible for the decrease of biodegradation.关键词：Magnesium Alloy;Microstructure;Biodegradation;Recrystallization
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发布时间：2023-12-18 - 摘要：<正>云南铜业科技发展股份有限公司成功研发纯铜及高含铜合金电动机转子。该项研究历时近10年,其成果填补了国内空白,云南铜业科技发展股份有限公司也成为全国中小企业股份转让系统（俗称"新三板"）首批全国企业集体挂牌的266家企业
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发布时间：2023-12-18 - 摘要：<正>重庆市科技攻关重大项目"汽车轻量化零部件开发与产业化"日前通过专家验收,研发出的镁合金零部件能实现汽车轻量化,同时达到节能的效果。重庆大学国家镁合金材料工程技术研究中心副主任龙思远介绍,镁是一种很轻的金属元素,与其他金属组成合
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发布时间：2023-12-18 - 摘要：<正>经过反复试验和摸索,近日,新兴际华集团新兴钢铁一钢成功研发了一种新型推管器,并成功应用于离心球墨铸铁管的管推和模具清理作业中,效果显著。目前,该发明已成功申报国家发明专利。目前,铸造行业常见的做法是推管器、道轨钢和清理模
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发布时间：2023-12-18 - 摘要：Wrought aluminium alloys are used increasingly for critical structure applications in the automotive and aerospace industries due to high strength and desirable toughness properties.It is difficult to obtain sound mechanical properties in the wrought aluminium alloys components by the near-net shape casting as a result of many microscopic defects.Plastic forming sucah as extruding forming can eliminating these microscopic defects,however,which requires high pressure,resuting in low product efficiency,increasing additional cost due to secondary forming processes such as cutting.Semi-solid metal processing integrated with the advantages of casting and forging,is one of promising technologies capable of producing high-integrity components.Therefore,many investigation on the forming of near-net shaped wrought aluminium alloy components have been actively conducted.The thixoformability,feedstock production,microstructure and mechanical properties of wrought aluminium alloy were reviewed,and the challenges and prospect of wrought aluminium SSM processing were approached.关键词：Wrought Aluminium Alloy;Semi-solid;Near-net Forming
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发布时间：2023-12-18 - 摘要：The filling process of the magnesium alloy mobile phone cover in mould was conducted by using appropriate process parameters.Multiple intersections were in the presence in filling process of liquid magnesium alloy.The cooler liquid alloy at the edge came together in the internal cavity with final filling parts in the interior of the cavity,resulting in gas entrapment and affecting the filling.By canceling the through-hole at the top and the bottom,and increasing the drainage slot,magnesium alloy liquid junction phenomena was relieved,and absence of the cooler liquid encountered in cavity could be observed, however,the final filling area was still retained in the cavity.By connecting through-hole in the middle of mould and opening overflow slots at the end position,the problems were eliminated in the filling process of magnesium alloy.Appearance detection and X-ray inspection of the actual castings revealed that the optimized mold design was feasible.关键词：Magnesium Alloy;Mobile Phone Cover;Mold;Optimization
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发布时间：2023-12-18 - 摘要：Filling process of 12tsteel ingots with different riser height was simulated by a software to predict the distribution of shrinkage cavity.The results show that shrinkage cavity in the precedent ingots is much deeper,which is well agreement with validation experiments.Therefore,the riser height was optimized by solidification simulation and validated by experiments.The results indicate that the optimized riser height can eliminate the shrinkage cavity,and enhance the steel ingots′quality and utilization.关键词：Steel Ingot;Solidification Simulation;Riser
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发布时间：2023-12-18 - 摘要：Squeeze casting process of the air conditioning compressor front cover was simulate by using ProCast software to predict entrapment-gas and shrinkage defects in the filling process with the pouring temperature of 660℃,the mold preheating temperature of 200℃and the pouring velocity of 150mm/s as well as the squeezing pressure of 70MPa.Liquid height difference in filling process can be narrowed through decreasing filling velocity.Entrapment gas in the castings can be eliminated with filling velocity of 100mm/s.With increasing in pressure and in die preheating temperature,shrinkage porosity is reduced.However,shrinkage porosity area occurs in the center after adjusting process parameters. Through imposing a secondary pressure on the central part,shrinkage porosity is eliminated.关键词：Squeeze Casting;Defect Prediction;Process Optimization;The Secondary Extrusion
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发布时间：2023-12-18 - 摘要：Design of gating system for die casting aluminum alloy cylinder block with cast-iron cylinder liner free was conducted.The cylinder block with uneven thickness has the characteristics of complicated shape and various structure.Meanwhile,pre-inserted cylinder liners are canceled,leading to a thicker wall-thickness.Single-side feeding is beneficial for the exhausting during pouring process,avoiding the occurrence of shrinkage holes（porosity）through exhausting gas in cylinder.Vacuum drawing can decrease gas hole greatly and densify the microstructure to improve the mechanical properties of the cylinder block.Cylinder insert mechanism was designed effectively,and its surface was treated to decrease frictional coefficient,which could decrease the harm to the mould during pull-out.关键词：Aluminium Cylinder Block;High Pressure Die Casting;Cast-Iron Cylinder Liners Free
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发布时间：2023-12-18 - 摘要：Effects of pouring temperature and solid solution temperature on the microstructure and mechanical properties of Al-6.8Zn-2.5Mg-2.0Cu alloy prepared by squeeze casting were investigated by tensile testing,OM（optical microscopy）,SEM（scanning electron microscopy）and XRD（X-ray diffraction）.The results show that compared with that in metal mold gravity casting,microstructure of the squeezing casting alloy can be refined significantly with decrease of the shrinkage defects,which are responsible for the improvement of mechanical properties.The primaryα-Al grain sizes are increased with the increase of pouring temperature in metal mold gravity casting,while their are decreased at first and then increased with the increase of pouring temperature in squeeze casting with the pressure of 60MPa. With pouring temperature of 720℃,the secondary dendrite arm spacing（SDAS）of the alloy reaches minimum size of about 26.3μm,and tensile strength and elongation of the castings reach 310MPa and 4.0%,respectively.After solution treatment at 470℃for 10hand aging at 130℃for 24h,the tensile strength and elongation of the castings reach 590 MPa and 4.7%,respectively,obtaining desirable strengthening-toughening effects.关键词：Pouring Temperature;Squeeze Casting;Al-Zn-Mg-Cu;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The vacuum counter-pressure casting process for thin-walled Al alloy adapter as a crucial structural component was optimized by simulating filling flow field,temperature field and shrinkage holes（porosity）.The numerical simulation results show that the optimized casting process with copper-cold iron for thin-walled Al alloy shell exhibits reasonable,in which the filling flow shows stable with temperature uniform distribution and absence of the predictable shrinkage porosity（holes）in the casting. Through using copper-based cold iron,the temperature distribution can be optimized effectively,thereby reducing the probability of shrinkage cavities and porosity in the casting.The practical production verifies that this process can produce qualified thin-walled Al alloy adapter casting.关键词：Thin-Walled Al Alloy Casting;Numerical Simulation;Shrinkage Porosity（holes）
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发布时间：2023-12-18 - 摘要：Effects of heat treatment,such as artificial aging（T1）,T5,T6,on microstructure and mechanical properties of high vacuum die casting AlSi10MnMgFe alloy plates were investigated.The results indicate that high vacuum die casting specimens exhibit sound structure and a better mechanical properties compared with conventional die castings.After artificial aging at 170℃for 8hours,the tensile strength and the elongation of the high vacuum die casting specimens reach 351.3MPa and 3.5%, respectively,which is the higher and lower those of the as-cast specimens,respectively.In addition, mechanical properties of the specimens produced are improved after T5and T6heat treatment.After T5 heat treatment,the elongation of the high vacuum die casting specimens is increased to 8.3%,obviously superior to that of as-cast ones.The tensile strength,yield strength,elongation and hardness of the T6 specimens reach 358.4MPa、286.6MPa、6.1%and 110.4,respectively.关键词：High Vacuum Die Casting;AlSi10MnMgFe Alloy;Heat Treatment;Mechanical Property
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发布时间：2023-12-18 - 摘要：According to the requirements of material,mechanical properties and shape structure of A390 hypereutectic aluminum alloy swash plate for automotive air-conditioner compressor,an indirect squeezing casting process was designed with function of local pressurized feeding.With the total squeeze casting pressure of 100MPa and the delayed time of 2.8s,the centre thick area of swash plate was pressurized locally with 180MPa for 6s,which could eliminate shrinkage defects in swash plate.The squeezed casting swash plate exhibits the features of dense structure and high dimension accuracy.Meanwhile, the average primary silicon size is only about 25μm with absence of poor primary silicon area obviously on the surface microstructure.In addition,the design has the superiority of auto-control pressurization feeding process and adjustable ability in pressurization starting-time and holing pressure time,suitable for a batch of production.关键词：Hypereutectic Aluminum Alloy;Squeeze Casting;Swash Plate;Compressor
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发布时间：2023-12-18 - 摘要：Size and quality of tube produced by horizontal continuous casting are closely related with structure of the crystallizer.Crystallizer is composed of graphite sleeve,graphite core.A crystallizer was designed for the ingot blank with the outer diameter of 90mm and the inner diameter of 40mm,and the graphite sleeve length,diameter,wall thickness,diameter of liquid injection hole,hole number, core taper,diameter of core inlet,diameter of outlet and the thickness of the mold base are 380mm,92 mm,14mm,10mm,4,1°,47.34mm,36mm and 45mm,respectively.The qualified TP2copper pipe was produced successfully with the crystallizer designed.关键词：TP2;Horizontal Continuous Casting;Crystallizer
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发布时间：2023-12-18 - 摘要：Unidirectional solidification equipment for horizontal Ohno continuous casting under argon protection conditions was designed and assembled by combining horizontal continuous casting with unidirectional solidification,which integrated with melting,holding,purification and solidification.The rods and wires with smooth surface and excellent properties were produced successfully with the system.The structure and operating mechanism of the continuous unidirectional solidification equipment were described.关键词：Unidirectional Solidification;Horizontal Ohno Continuous Casting;Wires
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发布时间：2023-12-18 - 摘要：<正>举办时间:2014-06-25举办地点:上海国际展览中心联系方式:上海时空展览服务有限公司地址:上海市市台路408号806室电话:（86）21 61243975传真:（86）21 6129 4111电邮:shskygq@163.com网址:www.wrchina.cn联系人:杨国庆先生13585756185
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发布时间：2023-12-18 -
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- 摘要：The rapid prototyping process based on SLS sand mold casting was described.SLS powder rapid prototying technlolgy can cancel pattern making and wax-pattern making in investment casting.SLS sand rapid prototying technology can avoid the complicated process of investment casting,especially for the rapid and economic advantages of shell and impeller with complex cavity in sand rapid casting design and manufacturing.Meanwhile,mold design and manufacture of the complex inner shell and impeller casting were performed.关键词：Rapid Prototyping;Sand Mold;Rapid Casting
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发布时间：2023-12-18 - 摘要：The investment casting cable car ring is composed of eight dis-uniform interval square tooth disc which is connected by triangle rib with square tube with a stop-end.The investment casting ring possesses the features of complicated shape and high position accuracy requirement.The gating system for the ring was rationally designed.The correction mould with cutting-free was adopted to correct the accuracy,which could not only improve the precision grade,but also improve the surface quality and strength of the ring.Using special monitoring apparatus to measure and square tooth groove combining with auxiliary position,the manufacturing precision of cable car ring could be ensured only working a middle hole.关键词：Cable Car Ring Casting;Correction Mould;Investment Casting
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发布时间：2023-12-18 - 摘要：Centrifugal casting is widely used in producing copper sleeves.Through controlling claded sand on surface of the mould,melting,filling of the alloy,gas pore and inclusion defects appearing in the surface were eliminated,obtaining excellent huge marine sleeves.关键词：Centrifugal Casting;Tin-Bronze;Metal Mould
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发布时间：2023-12-18 - 摘要：By using Zirconium-aluminum powder as refractory materials,phenol-aldehyde resin and silica sol as compound agglomerate,CMC and bentonite of natrium as compound suspending agent and isopropyl alcohol as isotopic carrier,based on the orthogonal testing,the alcohol-based coating for EPC steel castings was developed.The optimiced composition was presented by the experiment,and the comprehensive properties of the coating prepared were examined,obtaining a satisfied effects.关键词：EPC;Zirconium Aluminum Ore;Alcohol-Based Coating
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发布时间：2023-12-18 - 摘要：A kind of mullite-glass coating was prepared on the surface of metal mold by thermo chemical reaction method with Al2O3,SiO2and fusible glass powder.Influences of the process parameters on the bonding strength between coating and metal matrix were investigated.The phase compositions,microstructure of the coating and element distribution were analyzed by XRD（X-ray diffraction）,SEM（scanning electron microscope）,EDS（energy dispersedly spectrometer）,respectively.Experimental results show that reaction materials after ball-milling can improve the bonding strength of coating with substrate.The bonding strength of coating with substrate is increased firstly and then decreased with the increase of the reaction time,reaction temperature and the content of fusible glass powder.The coating which formed on the surface of metal substrate at 720℃for 2his tightly combined with substrate according to the mass ratio of Al2O3,SiO2and glass powder with 2∶1∶3,and the bonding strength reaches up to 8.95MPa.The interface bonding of coating and substrate is mainly characterized by chemical and diffusional bonding.The coating is mainly composed of 3Al2O3·2SiO2,Al2SiO5,amorphous glass powder and a small amount of Al2O3,Fe3Al,FeAl,SiO2.关键词：Casting Mold;Composite Coating;Manufacture Process;Coating Bonding Strength
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发布时间：2023-12-18 - 摘要：Cobalt-based functional gradient coating was prepared on alumina ceramic by microwave sintered with Co-based self-fluxing alloy powder and alumina ceramic powder as raw materials.Effects of different powder ball-milling time and sintering temperature on microstructure and bonding interface of coating were investigated,and relative density of the coating was measured.The results reveal that after balling for 24hours,the coating prepared at 1 300℃possesses homogeneous microstructure and desirable bonding interface as well as high relative density.关键词：Cobalt-Based Self-Fluxing Alloy Powder;Microwave Sintering;Relative Density
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发布时间：2023-12-18 - 摘要：Through comparing different measurement methods to bonding strength of copper-aluminum composites,a new stripping device for measuring bonding strength of composite laminate on the tensile tester with 90°stripping direction was designed.The structure characteristics of device was analyzed, and testing stability and measurement error of the device were examined.The results show that the device has the features of simple structure,low requirement for sample preparation and easy to use as well as desirable results reproducibility.Based on comparing peel strength measurements of six groups samples at 300℃for 4h,the result reproducibility is satisfied.The measurement error is 3.1%for peeling force measurement through measuring peeling strength of the samples at 250 ℃for 12h,meeting the measurement requirements.关键词：Compsites;Stripping Device;Peel Strength
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发布时间：2023-12-18 - 摘要：Through designing orthogonal experiment,modification treatments were performed on the primary Mg2Si phase in in-situ 20Mg2Si/Al composites.The results show that the optimized process parameter is presented as follows:0.03% P addition,0.4% mixed rare earth and the modification temperature of 780 ℃ as well as 30min of the modification time.The key influencing factors are P addition, and then mixed RE addition,modification temperature and modification time.关键词：P;RE;In situ 20Mg2Si/Al Composites;Orthogonal Experiment
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发布时间：2023-12-18 - 摘要：<正>德国汽车铸造厂,即德国黑色金属和有色金属铸造集团,计划在德国辛根建立球墨铸铁新成型线。该项目将于今年启动,在2015年下半年完成新生产线安装。据该集团透漏,项目总投资将高达5 500万欧元（约7 500万美元）。德国汽车铸造厂对承包建设新生产线的成型工艺设计师则未做任何透漏。新成型线将取代现有的已超过30年历史的成型线,其球墨铸铁的年产量将达到10万吨。
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发布时间：2023-12-18 - 摘要：Effects of Ca addition on microstructure and corrosion behavior of Mg-Al-Zn alloys at as-cast state and heat treatment state were investigated by the electrochemical method,weight loss method. The results show that the as-cast microstructure of Mg-Al-Zn-Ca alloy with varied Ca addition is composed of primary Mg phase andβ-Al12Mg17.With different Ca addition,there exists difference in amounts and shape ofβ-Al12Mg17phase in the alloy.After solid solution treatment,corrosion potential is shifted to positive,and corrosion current is decreased,which takes the attribution to improvement of corrosion resistance of the alloy prepared.The Mg-Al-Zn alloy with 1% Ca addition exhibits desirable corrosion resistance.关键词：Mg-Al-Zn Alloy;Microstructure;Corrosion
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发布时间：2023-12-18 - 摘要：Effects of Te addition,holding time and remelting times on the microstructure and mechanical properties of Al-7Si-0.3Mg Alloy with Te modification were investigated.The results show that Te exhibits a satisfied modification effect on Al-7Si-0.3Mg alloy.With 0.1% Te addition,tensile strength and elongation of the alloy with major eutectic Si particles reach 240.1MPa and 4.2%,respectively,increased by 31.1%and 133,3%,respectively,compared with those of un-modified alloy.After the alloy was modified for 6hand remelted by 3times,mechanical properties of the Te modified alloy keep a desirable state,which show Te exhibits satisfied anti-fading ability and anti-remelting behavior as a longduration modifier.关键词：Tellurium;A1-7Si-0.3Mg Alloy;Modification;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Influences of RE element Ce on as-cast microstructure of AZ91magnesium alloy were investigated by vacuum induction melting method.Then,the melting and solidification processes for rare earth magnesium alloy were analyzed by differential thermal analysis（DTA）with different cooling rates,such as 10K/min,20K/min,40K/min and 80K/min,in order to understand the formation regularity ofβ phase.The results show that Ce element can refine grain size in the microstructure of AZ91alloy and can effectively suppress the occurrence of divorced eutecticβ-Mg17Al12phase in grain boundary as a result of the formation of Al-Ce compound.Addition of 0.75%Ce can decrease the liquidus temperature of AZ91alloy from 605℃to 583℃.Under the condition of near equilibrium solidification,the increase of cooling rate results in insufficient solute diffusion ahead of liquid-solid interface front,which enhances the relative area of eutectic peak in DTA curves and indicates the increase of volume fraction of divorced eutecticβ-Mg17Al12phase.In addition,the lamellar volume fraction for secondary precipitatedβphase is decreased,which can be attributed to the decrease of eutectoid transition time because of higher cooling rate.关键词：Rare Earth Magnesium Alloy;βPhase;Differential Thermal Analysis;Cooling Rate
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发布时间：2023-12-18 - 摘要：The ladder-type Al-Si-Cu-Mg-Ni alloy samples were prepared by metal mold at different cooling rates and treated by T6heat treatment.The microstructure and mechanical properties of the Al alloys under different conditions were investigated by optical microscope（OM）,X-ray diffractometer（XRD） and scanning electron microscope（SEM）.The results indicate that the secondary dendrite arm spacing（SDAS）of alloy is decreased,and the tensile strength,yield strength,hardness and elongation are increased gradually with the cooling rate increase.Heat treatment can improve significantly the mechanical properties of the alloy.After T6treatment,the uniform and fine eutectic-Si is distributed dispersedly in theα-Al matrix.The tensile strength,yield strength and hardness of the alloy with 20mm in cross-section thickness after heat treatment reach 367 MPa,229 MPa and 125HB,about 49.2%,54.7% and 34.3% higher than those of the as-casted alloy,respectively.Tensile fracture of the alloy is characterized by a mixed morphology of a large number of dimples and a number of cleavage plane.关键词：Al-Si-Cu-Mg-Ni Alloy;Cooling Rate;T6Heat Treatment;Microstructure
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发布时间：2023-12-18 - 摘要：The orthogonal experiment of heat treatment process was designed for 2524aluminum alloy. Combined with the conductivity testing,range analysis and variance analysis of orthogonal experiment were carried out.The process was optimized by artificial BP neural network model,and the desirable heat treatment parameters of aluminum alloy were presented as follows:solid solution treatment at 515 ℃for 11h,and aging treatment at 185℃for 5h.The results indicate that,this model can better reflect the relationship between heat treatment process parameters and electric conductivity of aluminum alloy,and the maximum relative error of BP network forecasting is 2.19%,showing a higher prediction accuracy.
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发布时间：2023-12-18 - 摘要：The mechanical properties at room and high temperature,chemical composition,microstructure of the zinc alloy（ZA27alloy）worm gear in elevator traction machine were analyzed by electron universal test machine,spectrum analyzer,metallurgical microscope and scanning electron microscope.The results show that inclusion,shrinkage porosity,pore and partial over-loading are responsible for failure of the zinc alloy worm gear.Some feasible ways were presented to eliminate casting defects,and the working accuracy was improved to reduce the possibility of partial over-loading,ensuring the safe and effective runing of the elevator.关键词：Elevator Traction Machine;Zinc Alloy Worm Gear;Failure Analysis
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发布时间：2023-12-18 - 摘要：Cu-0.33Cr-0.06Zr alloy was treated by solid solution treatment,cold deformation and aged with different aging time and different current intensities at 450℃to understand the effects of different DC current intensities on electric conductivity of the alloy aged.The results show that compared with the alloy aged without DC current,the electric conductivity of the alloy aged with 100A/cm2 DC current is lower,while the one aged with 400A/cm2 DC current is higher with a fixed aging temperature and time.The electric conductivity of the alloy aged is firstly decreased and then increased with the increase of current intensity at a given aging time.With 400A/cm2 DC current,the electrical conductivity of alloy with aged for 2hours is increased to 49.53MS/m,equivalent to the alloy aged 6hours without DC current.The results reveal that high current intensity can promote the precipitation of solute element and improve the efficiency of precipitation greatly,which are attributed to co-action of the Joule heating and electron wind force to vacancies and dislocation.关键词：Cu-Cr-Zr Alloy;DC;Current Intensity;Aging;Conductivity
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发布时间：2023-12-18 - 摘要：The application of continuous extrusion technology in the production of oxygen-free copper bar was described.Through adopting on-line degassing,new up-drawing continuous casting equipment with new mould and continuous extruded technology,the oxygen-free copper bar with oxygen content less than 0.0005%and electric conductivity more than 58.58MS/m was produced successfully by melting, up-drawing Cu bar,continuous extrusion,tensile and finishing.The technology exhibits short procedure,high efficiency and high quality rate.关键词：Oxygen-Free Copper Bar;Continuous Extrusion;Electric Conductivity
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发布时间：2023-12-18 - 摘要：<正>20140501 Huang H,Wang Y X,Fu P H,et al.浇注和模具温度对AD91D和Mg-3Nd-0.2Zn-Zr合金流动性的影响.International Journal of Cast Metals Research,2013,26（4）:213-219.流动性和热裂性是评价合金铸造性能的两项基本指标,其影响因素众多,而最主要的因素为模具温度（过热度）和浇注温度（TDSM）。对比研究了模具温度和浇注温度对传统商业镁合金AZ91D和稀土镁合金NZ30K流动性与热裂性的影响。结果显示,提高浇注温度和模具温度均可以显著改善合金的流动性
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发布时间：2023-12-18
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