最新刊期
卷 ， 期 6 ， 2007
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- 摘要：The Cu60Zr30Ti10 bulk amorphous alloy with the size of 75mm in length,10 mm in width and 1mm in height has been prepared with commercial pure materials by water cooled copper mold vacuum casting.The surface of the amorphous alloy was cladded by YAG laser beam,and the microstructure and micro-hardness of the alloy in the cladded zone have been observed by X-ray diffracto-meter,optical microscope and micro-hardness meter at different depths.The results show that two-layer new microstructure can be formed in the bulk amorphous alloy after laser cladding,in which the hardness and corrosion resistance of the second layer in the middle with the thickness of about 200 μm are evidently superior to those of the matrix,reaching HV872.5 in micro-hardness.关键词：Bulk Amorphous Alloy;Laser Cladding;Microstructure;Micro-Hardness
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发布时间：2023-12-18 - 摘要：Al-Cu-Mg-Ag-Mn alloys with different Cu and Mg contents were prepared by ingot metallurgy and thermo-mechanical treatment.The effects of Cu and Mg contents on the microstructure and mechanical properties of the alloys have been investigated by tensile testing,differential scanning calorimetry（DSC）,scanning electron microscopy（SEM） and transmission electron microscope（TEM）.It was found that the aging hardening and tensile strength of the alloys can be improved by increasing Cu and Mg content.Increase of Cu content can not only improve the solid solution strengthening effects of the alloy,but also play a role of second phase strengthening due to the creation of θ（CuAl2） phase with excessive Cu addition,which is beneficial to improving the elevated properties.The strengthening phase in the alloys is composed of plate-like Ω phase and minor θ’ phase with peaking aging at 185 ℃,in which with increasing Cu content,the volume fraction of plate-like Ω phase can be increased,and with increasing Mg content,the aging hardening of the alloy can be accelerated with the size of the plate-like Ω phase decrease.关键词：Aluminum Alloy;Mechanical Properties;Aging;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of different melt-treatment methods on tensile properties at elevated temperatures and microstructure of the Al sheet for pressure cans have been investigated by OM（optical microscope）,DTA（differential thermal analysis）,SEM（scanning electron microscope）,EDAX（X-ray energy diffraction analysis） and TEM（transmission electron microscope） based on tensile testing at elevated temperatures.The results show that the existence of metallurgical defects can be responsible for the restraint of high temperature deformability and directly affect the crack propagation in the aluminum sheet as the key crack resource.Compared with the un-treatment and conventional treatment,the high-efficient melt-treatment can remarkably improve the metallurgical quality and uniformity of high temperature deformation,greatly raising the high temperature plasticity due to transgranular micro-pore gathering crack mode.The high temperature plasticity of high-efficient melt-treated aluminum sheet would be greatly deteriorated as a result of the coarsened grain size and creation of Fe（Si） phase with the deformation temperature more than 500 ℃,so the proper deformation temperature should be chosen in the range of 400450 ℃.The main plastic deformation properties of the aluminum sheet from lower grade commercially pure aluminum after high-efficient melt-treatment can reach or exceed the properties of using materials,which shows the availability of lower grade aluminum raw materials.关键词：Aluminum;Melt-treatment;Tensile Properties at High Temperature;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：The effects of electric pulse modification（EPM） on the hot cracking tendency of Al-5Cu alloy have been investigated.The results indicate that the hot cracking tendency can be effectively restrained after treated by electric pulse modification with different parameters.Moreover,the hot cracking critical stress of alloy treated by EPM is increased by 3 times or so than that of the samples without treatment,which is attributed to the grain refinement of Al-Cu alloy and the decrease of eutectic phase in boundary as well as narrow of solidified temperature zone with EPM treatment.关键词：Hot Crack;Al-Cu Alloy;EPM;Refinement
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发布时间：2023-12-18 - 摘要：Dry-sliding wear behaviors of two kinds of CuZnAl（RE） shape memory alloys（different transformation temperatures） after heat treatment have been examined in the conditions of different transformation temperatures,different loads for different wear periods,and the wear surface and debris have been observed by SEM and XRD.In addition,the comparison of the alloys with bronze and brass is conducted.The results show that the forging and grain refinement can improve the wear resistant of the CuZnAl（RE） SMA.Under dry sliding conditions,the wearability of martensite phase in CuZnAl（RE） SMA is higher than that of β phase.The wearability of the CuZnAl（RE） SMA treated by two grade aging is better than that of the ones treated by grade quenching.Meanwhile,the wear behavior of CuZnAl（RE） SMA is superior to that of bronze and brass.The wear mechanism of CuZnAl（RE） SMA is controlled by adhesion,delamination and abrasive wear.关键词：CuZnAl（RE） SMA;Wear Resistance;Superelasticity;Martensite Transformation
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发布时间：2023-12-18 - 摘要：Effects of heat treatment on microstructures and properties of 7B04 aluminum alloy thick plates have been investigated by optical microscope and transmission electron microscope,tensile testing and electrical conductivity testing.The results show that the optimal solid solution is treated at 470 ℃ for 240 min.Maximum tensile strength of 621 MPa can be observed with lower electric conductivity only 18.3 MS/m,after aged at 120 ℃ for 22 h.Although the tensile strength of the alloy is decreased by 10%12%,compared with that of T6 treated alloy,the electric conductivity is evidently improved by 21.3 MS/m after two-step T74 aging treatment.The high strength and high electric conductivity can be observed by RPA treatment,equivalent to T6 alloys in strength and to T4 alloy in electric conductivity.Amounts of fine disperoids are distributed into the RPA alloy with coarse and fully discontinuously distributed precipitation phase from the boundary.关键词：7B04 Aluminum Alloy;Solid Solution;Aging;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The predicting model for relationship between elongation and deformation parameters of superplastic lead brass has been established based on standard feed-forward BP neural network.The elongation of the superplastic lead brass can be effectively predicted,such as maximum error lower than 4.81%,by training the established model based on experimental data,realizing the non-linear mapping between different deformation parameters and elongation.The predicted values of the elongation is well in agreement with experimental results,which provides a reference to theory and experiment of superplastic forming parameters of lead brass bearing cage.关键词：Lead Brass;Superplastic;Elongation;BP Neural Network;Prediction Model
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发布时间：2023-12-18 - 摘要：Numerical simulation of thixoforming for high fraction semi-solid magnesium alloy has been conducted to analyze the stress,strain distribution and temperature field during thixoforming process,and forming characteristics between semi-solid billets and conventional billets has been compared.The results indicate that semi-solid magnesium alloy exhibits low deformation resistance and uniform stress and strain distribution,which provides a reference to optimizing thixoforming parameters for semi-solid magnesium alloy.关键词：Magnesium Alloy;High Fraction Semi-solid Billets;Thixoforming;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Control equations of kinetics and dynamics among the plunger,shot sleeve and liquid metal have been established to simulate the 2D flow field of liquid metal in shot sleeve based on conventional flow field simulation,in which the boundary and initial conditions among the threes are considered.The effects of different velocities of plunger on the entrapped-gas defects in liquid metal in shot sleeve have been approached,which provides a reference for the selection of slow-injection velocity in practical die casting.关键词：Shot Sleeve;Flow Field;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The filling process was simulated to analyze local overheat in die resulting from irrational filling and cold shut occurred in far-end in aluminum alloy engine bracket.The results indicate that the defects are caused by irrational ingate design.Based on above analysis,the ingate design and the die structure have been optimized.The production verifies that the desirable filling can be formed in the optimized ingate,which plays the uniform temperature distribution in the die and eliminates the cold shut in filling far-end in the bracket.关键词：Aluminum Alloy;Die Castings;Numerical Simulation;Ingate;Process Optimization
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发布时间：2023-12-18 - 摘要：The process used to produce the WC particle reinforced steel/iron matrix composites was reviewed including cast-infiltration method,powder metallurgy,overlay welding,electro-slag casting,and the selection of tungsten carbide and the steel/iron base,interface reaction and bonding strength,properties of application of the composites.The effects of parameters,such as binder,additive,shape and size of WC particle,pouring temperature,on the composites fabricated by cast-infiltration method have been paid attention to.It is pointed out that the cast-infiltration method is a promising technique for fabricating the WC particle reinforced steel/iron matrix composites,while the combination of SHS with cast-infiltration is a very potential approach.It is a spotlight on cast-infiltration for fabricating the composites with composite layer of 10 mm in thickness and on stabilization of composites process as well as the key technology of industrialization.Surface wear resistant composites are more suitable for parts in the conditions of local wear and small angle erosion,and the process and the composites should be selected according to the wear conditions.关键词：Particle Reinforced;Tungsten Carbide;Cast-nfiltration;Steel/iron Matrix Composites;Wear
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发布时间：2023-12-18 - 摘要：The extreme ponderance for environmental protection and imminence of solving environmental problems in the China,especially austere environmental problems about foundry industries were reviewed.Aiming at the existing problems,some countermeasures were given.关键词：Foundry Industries;Environmental Protection;Environmental Pollution
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- 332
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发布时间：2023-12-18 - 摘要：Semi-solid Al-5Cu alloy was prepared by ultrasonic stirring.The effects of important parameters,such as melt temperature,the ultrasonic treatment time and output power of ultrasonic stirrer,on the semi-solid structure of the alloy have been observed The results show that finer primary phase can be observed with increasing the melt temperature in the range of 610 to 660 ℃.In addition,the primary phase in the Al-5Cu alloy can be converted from coarse dendrite into fine spheroids with increasing the output power and time of ultrasonic stirrer at 660 ℃.关键词：Semi-solid;Ultrasonic Stirring;Al-5Cu Alloy;Microstructure
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发布时间：2023-12-18 - 摘要：Application of the Pro/E software and its secondary developing tool Pro/TOOLKIT to designing the die casting die for box parts was described.The structure of the design system of die casting die for box parts were analyzed,focusing on the composition,which provides a reference for other die casting die for box type parts.关键词：Pro/E;Secondary Development;Die Casting Die for Box Parts
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发布时间：2023-12-18 - 摘要：The origination of some defects encountered in aluminum wheel for the Peugeot car,such as crack,porosity,gas hole,was analyzed.Based on above analysis,the wheel structure,mould,alloy and processing as well as coating were improved.The production verified that the qualified rate of the products is increased from 40% to 87%90%.关键词：Wheel Structure;Smelting;Coating
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发布时间：2023-12-18 - 摘要：Design and development of the remote monitoring and controlling system for die casting workshop based on controller link bus technique with the requirements for integrative management of die casting workshop have been described including the system structure,communication and the implementation of software and hardware for remote monitoring terminal.All the machines in the workshop and the remote monitoring terminal are taken as the nodes in the controller link system.Based on the communication capability of the system,an Omeron PCI board was used as hardware structure for communicating PLC with master machines to realize the high speed exchange of data.The Kingview software was used in the terminal to realize the remote monitoring and management for die casting workshop.关键词：Controller Link Network;Remote Monitoring;Die Casting
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发布时间：2023-12-18 - 摘要：The gear planetary frame has complicated configuration and cavity and dispersed hot spot due to uneven thickness.The inner core pulling of The gear planetary frame can be solved by adopting combinative core.Compared with urea core,the process can decrease the costs of mold making and casting;compared with combinative wax pattern,it can improve the accuracy of the castings.The shrinkage hole in the casting can be effectively eliminated by using the cross gating system.关键词：Planetary Frame;Investment Casting;Pattern Design;Combinative Core;Feeding
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发布时间：2023-12-18 - 摘要：High temperature wear resistance of Cr-Mo-V cast hot-forging tool steel was examined on a pin-on-disk high temperature wear tester,which is compared with H13 tool steel.The microstructure and morphology of the cast steel were observed by TEM and SEM.Meanwhile,the effects of constituent and microstructure on the wear resistance of the cast steel were described.It is found that the microstructure of Cr-Mo-V cast hot-forging tool steel is composed of tempered troosite.Predominant carbide is（Fe,Cr）3C with tempered at 440 ℃ while it is VC and minor（Cr,Fe）7C3 and Mo2C with tempered at 600 ℃.The high temperature wear resistance of the Cr-Mo-V cast hot-forging tool steel is evidently superior to that of H13 tool steel produced at home,and is equivalent to that of ones produced at aboard,exhibiting low melting cost and high ratio of property to price as well as rational alloying composition design.关键词：Cast Steel;Hot-forging Tool;High Temperature Wear Resistance;Microstructure;H13 Steel
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- 240
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发布时间：2023-12-18 - 摘要：Effects of industrial frequency electromagnetic field on surface quality,solidification structure,solute segregation and mechanical properties of Al-1Si alloy wire billets with 10 mm in diameters in horizontal continuous castings have been investigated.The results show that the surface quality of the billets can be greatly improved,where the surface roughness is decreased from 40 μm to 20 μm with exciting current of 100 A.The microstructure of the Al-1Si alloy can be refined with uniform grain size.The solid solution degree of Si element and its distributed uniformity in α（Al） matrix can be improved as a result of restraining solute segregation.Based on above reasons,the tensile strength and elongation of the Al-1Si alloy wire billets are increased by 16.5% and 36% respectively.关键词：Horizontal Continuous Casting;Industrial Frequency Electromagnetic Field;Al-1Si Alloy
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发布时间：2023-12-18 - 摘要：The microstructure,mechanical properties and electric properties of as-cast and cold worked Be-Ag-Cu alloy rod in directional continuous solidification have been investigated.Directional solidification Be-Ag-Cu alloy rod possesses continuous fibrous structure,which exhibits higher strength and plasticity as well as high electric conductivity compared with continuous directional solidification single crystal copper bar.Fracture morphology observation shows that the crack is characterized by transgranular ductile crack,showing peak-like in micro-fracture and oblates with many sliding lines in macro-fracture.The compact fibrous structure in the Be-Ag-Cu alloy rod can be observed,meanwhile the electric conductivity is slightly decreased and strength is greatly improved after severe plastic deformation.关键词：Directional Solidification;Fibrous Structure;Strength;Electric Conductivity;Single Crystal Copper
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发布时间：2023-12-18 - 摘要：The microstructure and dry sliding wear behavior of V-Cr composites layer on the surface of ZG310-570 cast steel prepared by V-EPC cast-infiltration method have been investigated.The result indicates that the prepared composite layer possesses compact microstructure and absence of defects in the composites layer is found.There exists typical carbide morphology in composites layer,such as strip and bar,chrysanthemum,short bar and spheroids.The weight loss of the composites layer is increased with raising loading in the range of 300750N.The desirable wear resistance of the composites layer can be observed with cast-infiltration agent containing 35% Cr-Fe and 40% V-Fe,which is 16.5 times of that of ZG310-570 cast steel.The wear mechanism of the cast-infiltration layer exhibits abrasive wear,plastic deformation and delamination.关键词：V-EPC Cast-infiltration;V-Cr Composites Layer;Microstructure;Dry Sliding Wear
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发布时间：2023-12-18 - 摘要：The defects in large section aluminum alloy perpendicular clamp in permanent mold gravity casting were analyzed.The casting defects,such as shrinkage hole,contracted cave and crack,in the castings have been effectively eliminated by vertically assembling casting and perpendicularly parting,which improves the bearing load by 30% than designed ones.The qualified rate of the product reaches 98% and the production efficiency is increased by 35%.关键词：Large Section Perpendicular Clamp;Permanent Mold Gravity Casting;Casting Defects
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发布时间：2023-12-18 - 摘要：Effects of diffusion time on the depth of diffusion layers in hot dip pure aluminized steel and aluminized steel with RE have been examined,meanwhile,the RE distribution in the diffusion layers has been probed by SEM（scanning electronic microscope） and EPMA（electron probe micro-analyzer）.The depth of diffusion layer in the samples with different diffusion time at 850 ℃ was measured,which shows approximately square parabola law between depth of diffusion layer and diffusion time.The experimental results reveal that the RE can penetrate into the diffusion layer and increase the penetrated rate by 25%30% as well as decreasing diffusion active energy by 7857.39 J/mol.关键词：Rare Earth;Hot Dip Aluminized Steel;Diffusion Layer;Growth Law;Diffusion Activation Energy
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发布时间：2023-12-18 - 摘要：Sterling silver alloy was susceptible to form firescale in heat working,such as casting and welding.The formation mechanism of firescale in the sterling silver alloy has been discussed by analyzing the firescale structure using XRD and OM.The results show that the copper is oxidized selectively to form cuprous or cupric oxide on the surface with sterling silver alloy heated,including outer oxidization layer and inner oxidization layer.However,the inner oxidization layer would be left during the oxidized samples pickled in dilute sulfuric acid,which exhibits firescale after the sample polished.关键词：Sterling Silver Alloy;Firescale;Formation Mechanism
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发布时间：2023-12-18 - 摘要：The mechanical alloying process of Nb and Cr mixed powder（1:2 in molar ratio） has been analyzed by high energy ball milling for Nb-Cr binary alloy powder in case of the mass ratio of steel ball to powder of 13:1,and the phase constituent of the Nb-Cr powders has been observed by XRD（X-ray diffraction）.The results reveal that firstly,the Nb（Cr） solid solution phase can be formed with ball milling for 20 h,then amorphous phase appears after 45 h,further,the crystallization of amorphous phase occurs for 159 h.The thermo-kinetic model of mechanical alloy process of Nb-Cr series has been established by referring to the Miedema semi-empiric theory to describe the phase transformation of Nb-Cr system during milling.The thermo-kinetic simulation verifies that the Nb-Cr binary system possesses thermo-kinetic driving force forming amorphous phase,solid solution phase and compound.The simulated results are well in agreement with the XRD analysis ones.关键词：Thermo-kinetics;Nb-Cr System;Mechanical Alloying;Miedema Model
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发布时间：2023-12-18 - 摘要：The 7050 aluminum alloy billets with and without refiner have been prepared by conventional continuous casting and by electromagnetic continuous casting.The effects of Al-Ti-B refiner and electromagnetic filed on grain refinement in the aluminum alloy billets have been described.It was found that the grain can be effectively refined by adding 0.2% Al-Ti-B master alloy and by electromagnetic field.Furthermore,the Al-Ti-B master alloy is still valid in the condition of electromagnetic filed,and the refinement effects of co-action of electromagnetic field and Al-Ti-B master alloy are superior to those of only electromagnetic field or only master alloy,in which the grain size of billets edge and center reach 70μm and 53 μm respectively.关键词：7050 Aluminum Alloy;Grain Refinement;Refiner;Electromagnetic Continuous Casting
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发布时间：2023-12-18 - 摘要：The existence behavior of Sr and Nd elements in microstructure of Mg-6Al-2Sr-xNd magnesium alloy was observed,and the effects of Nd content on the mechanical properties of the alloy at room temperature were investigated.The results show that net-like Al4Sr phase is distributed along the grain boundary,and particle-like or acicular Al11Nd3 phase is precipitated from both grain and grain boundary.The increase of strength of the alloys is attributed to the Al4Sr phase inhibiting the sliding of grain boundaries and the Al11Nd3 phase pining the dislocation effectively.The maximum values of tensile strength,yield strength and elongation of the alloys can be observed with 1.0% Nd content.关键词：Magnesium Alloy;Sr;Nd;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The solidification behavior and microstructure of Sn-30Sb alloy which had been melted below and above the temperature-induced liquid structure transition were observed by forced cooling.The results show that compared with melt at holding temperature before liquid structure transition,the alloy melted above liquid structure transition temperature needs higher supercooling degree during solidification,and SnSb compound phase becomes finer and more dispersive,which is attributed to the debonding of atomic cluster in the melt structure at the liquid structure transition temperature range of 8761 135 ℃,resulting in the uniform distribution of the melt to inhibit the nucleation and growth of primary,further to promote peritectic reaction and to finally refine the solidification structure.关键词：Sn-Sb Alloy;Liquid-liquid Structure Transition;Solidification Structure
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发布时间：2023-12-18 -
Preparation of Nanometer-scale Copper Powders by Hydrogen DC （Direct Current） Arc Plasma Evaporation
摘要：We have developed a hydrogen DC arc plasma evaporation apparatus to prepare nanometer-scale copper powder with 99.99% pure copper.The effects of three processing parameters,including current,hydrogen/Ar ratio and air pressure,on the product rate and granularity of copper powder have been analyzed systematically.The composition,morphology,crystal structure and particle distribution in the copper powders have been analyzed by XRD,TEM and ED as well as Simple PCI software.The results show that the dominant factors influencing the product rate and average particle diameters are current and H2/Ar ratio.The prepared nanometer-scale copper powder is characterized by multi-crystal structure with the average diameters in the range of 29 to 116 nm.The product rate is increased by 27.65 time compared with the results by other investigation results at the same parameters.关键词：DC Arc Plasma Evaporation;Nanometer-scale Copper Powder;Preparation- 2
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发布时间：2023-12-18 -
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