最新刊期
卷 35 ， 期 8 ， 2015
- 摘要：Grain size changes of as-cast Mg-3Al alloy were investigated through adding Fe into melts then treated by carbon inoculation based on the native grain refinement,and influencing mechanism of Fe was also analyzed and discussed.The results reveal that the grain size in Mg-3Al alloy is increased firstly and then decreased with the increase of Fe.Grain refining efficiency of carbon inoculation is notable when the Fe content is low,while it is fade with Fe content increase.The influencing mechanisms of Fe element on grain size of Mg-3Al alloy is related with the characteristics of nucleuses in solidification induced by Fe.关键词：Magnesium Alloy;Grain Refinement;Heterogeneous Nucleation
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发布时间：2023-12-18 - 摘要：Effects of aging time on microstructures and corrosion resistance of AZ91 D magnesium alloys were investigated under 1GPa through XRD（X-ray diffraction）,OM（optical microscopy）,SEM（scanning electron microscopy）and polarization curves.The results show that,with aging time increase,the number of twin crystal is increased firstly and then decreased.Moreover,a mounts of dynamic recrystallization grains can be observed in twin boundaries and twin-intersection zone.After aging treatment for60 min,the grain size in AZ91 D magnesium alloys exhibits fine and uniform with the satisfied corrosion resistance.关键词：AZ91D Magnesium Alloys;Aging Time;Microstructures;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：The Al-5Ti-1Bmaster alloy was prepared by the equal channel angular pressing（ECAP）,and the grain refining performance of Al-5Ti-1Bmaster alloy before and after ECAP for commercial purity Al was evaluated.Effects of the Ti conceng and the growth restriction factor on the grain size of the commercial purity Al were investigated.With the increase of Ti contents,the nuclei particles are increased and the grain size of the commercial purity Al is decreased from approximately 1 220μm to about 70μm.Grain refinement ability of Al-5Ti-1B master alloy by ECAP was improved significantly.The relation between the grain size and the growth restriction factor was built up.关键词：Al-Ti-B Master Alloy;TiAl3Phase;ECAP Deformation;Grain Refinement
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发布时间：2023-12-18 - 摘要：There are many advantages to produce the aluminum alloy housing castings by digital precision forming technology without pattern.Based on the structure characteristics of complex housing castings,the flow field and temperature field in casting process and the casting process were designed and optimized by simulation software.Combined with the digital forming technology without pattern casting,a systematic,fast and low cost process for new product development from product process design to real casting was established.The process integrates the CAD/CAE/CAM technology without the mold any more,which can decrease the development period and reduce the rejection rate.关键词：Casting without Pattern;Numerical Simulation;Aluminum Alloy Casting
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发布时间：2023-12-18 - 摘要：Effects of aging temperature,aging time and different cold deformation on microstructure and properties of Cu-Ni-Si-Cr alloy were investigated.The results show that after solution treatment,the electrical conductivity and microhardness of the alloy aged at 500℃for 4hreach 22.34MS/m and 220.1HV,respectively,exhibiting favorable comprehensive properties.The desirable properties can be obtained with electrical conductivity of 22.50 MS/m and microhardness of 267.5 HV after 80%cold deformation by aging at 450 ℃for 2h.The fine and dispersedly precipitates can be observed in Cu-Ni-SiCr alloys,which are revealed as Ni2 Si and Cr elemental by electron diffraction analysis.关键词：Aging;Cold Deformation;Electrical Conductivity;Microhardness
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发布时间：2023-12-18 - 摘要：Additives and inhibitor were added into micro-emulsion to understand effects of metal cutting fluid on the friction and corrosion inhibition performance of 6061 alloy and 7050 alloy.The results show that,the addition of S-830,410-P and LG700 additives with different concentration,the friction coefficient and wear rate are decreased.At a certain concentration range,with the increase of the concentration of inhibitor,the corrosion current density is decreased,and the inhibition efficiency is increased gradually.E9600 corrosion inhibitor is an anodic inhibitor,while JP inhibitor is acathodic inhibitor.The test results of electrochemical corrosion and liquid phase semi-immersion test results are consistent.关键词：Metal Cutting Fluid;6061Alloy;7050Alloy;Friction;Corrosion
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发布时间：2023-12-18 - 摘要：The semi-solid casting method was applied for the preparation of Cu40Zr44Ag8Al8 amorphous composites.Effects of holding time on microstructure and mechanical properties of the amorphous composites prepared were investigated by X-ray diffraction（XRD）,simultaneous differential scanning calorimetry（DSC）and scanning electron microscope（SEM）,TEM,EPMA,uniaxial compression experiment.Results show that thermal stability of the amorphous matrix is reduced,and spherical particles in the composite are increased and refined,whereas the strength of the composites is declined with increasing in the holding time.Fracture analysis reveals that precipitation types in the composites is responasible for mechanical properties of the amorphous composites.Precipitation of the brittle intermetallic compounds Al3 Zr can take the change of stress concentration,leading to the decrease of the strength of the sample.关键词：Semi-solid Casting;Bulk Metallic Glass;Composites;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Effects of back pressure on ECAE Ti alloy were investigated.The results show that with the increase of the back pressure,the deformation uniformity of the samples is improved as a result of decrease of outer-round angle,meanwhile,the loading is increased,which increases the requirement of mould and extruding equipment.The temperature field at the whole sample exhibits slightly change,and it becomes more uniform at the bottom compared with that with absence of back pressure.The maximum equivalent strain at the bottom sample is increased with the backpressure increases gradually,however,excessive back pressure can cause strain uneven distribution.The maximum principal stress is decreased with the pressure increase,which reduces effectively the crack tendency of specimen surface.关键词：Titanium Alloy;ECAE;Back Pressure;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Based on the technical characteristics of friction stirring welding,with the help of multi-field coupling reasonable solution techniques,Comsol Multiphysics software was used to establish thermal mechanical coupling finite element model of friction stirring welding A356.0-T61 aluminum alloy.JMatPro was applied for defining thermo-physical properties of A356 aluminum alloy material with temperature changes,and effects of axial down-pressure,rotation speed,welding speed and other factors on the temperature field and stress distribution evolution of friction stirring welding A356 aluminum alloy were analyzed mainly.The results show that the welding speed has domonant in influence on ellipticity of elliptic distribution of FSW isotherm shape.The largest welding equivalent stress is located at outside edge of SAZ,near which the small areas of low stress distribution shows discrete state.The effect significance order of process parameters on friction stirring welded A356 aluminum alloy temperature field distribution is presented as follows:welding speed > head rotation speed > axial downward pressure,and the effect significance order of process parameters on friction stirring welded A356 aluminum alloy stress distribution is presented as follows:axial downward pressure> welding speed>rotation speed.关键词：A356 Aluminum Alloy;Welding Process;Finite Element Analysis;Friction Stirring Welding
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发布时间：2023-12-18 - 摘要：The ProCAST software was applied to simulate the casting process of aluminum alloy housing.Through comparing the simulation results with the actual production,the results are well in agreement with the actual ones,which verifies that the simulation software can provide technical support for aerospace premium engineered casting foundry process design.关键词：Premium Engineered Aluminum Alloy Castings;Process Design;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Aluminum alloys melting plays a critical role in casing production.And the melting quality controls the performance of the casings.The heat transfer behaviors in induction melting process of aluminum alloys may be helpful for better controlling melting processing parameters and obtaining better aluminum alloy melt quality.A mathematical model of coupling electromagnetic and temperature field in induction melting process of aluminum alloys was built up.The numerical solution based on finite difference method（FDM）was given,and a self-developed program was made to visualize 3D melting heat transfer behavior in aluminum alloys induction melting process.In addition,effects of different electromagnetic parameters on melting heat transfer behavior were described.关键词：Aluminum Alloys;Induction Melting;Heat Transfer;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Microstructure evolution of IN690 superalloy during extrusion tube process was visualized by numerical simulation.The evolution process of dynamic recrystallization（DRC）and the average grain size at different extrusion parameters were presented.The results show that at given extrusion speed and extrusion ratio,with the increase of extrusion temperature,complete dynamic recrystallization region is expanded,and the average grain size is increased too.At fixed extrusion speed and extrusion temperature,with the increase of extrusion ratio,complete dynamic recrystallization region is expanded,while the average grain size is decreased.From the inside to outside of the tube wall thickness direction,the average grain size is increased firstly and then decreased.The relative error of grain size between simulation results and experimental ones was less than 12%.关键词：IN690Super Alloy;Dynamic Recrystallization;Grain Size;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Progress in strengthening high strength and high conductive copper alloys was reviewed from views of alloying and processing technique.The method and mechanism of processing high strength and high conductive copper alloys by alloying technique were described.The progresst in processing technique of high strength and high conductive copper alloys was introduced,focusing on the applications of composite method,rapid solidification,severe plastic deformation and directional fiber reinforced in enhancing high strength and high conductive copper alloys.关键词：Cu Alloy;High Strength;High Conductivity
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发布时间：2023-12-18 - 摘要：Effects of aging time on microstructures and mechanical properties of thixoforged AZ63 magnesium alloy were invstiagted.The results indicate that aging time affects the precipitation sites,volume fraction and shape of aging precipitation,and finally affects the mechanical properties and fracture behavior.The improvement of mechanical properties is attributed to the dispersion strengthen of continuous precipitation,and the decrease of mechanical properties is resulted from the harmful discontinuous lamellar precipitation.With the aging time increase,the fracture mode is transformed from intergranular into transgranular fracture.With aging at 215 ℃ for 2h,the tensile strength reaches 348 MPa,and hardness reaches 69（HV）with aged for 8h.Comparing with thixoforged AZ63 alloy,the tensile strength and hardness of the aged alloy are increases by 53% and by 26%,respectively.The fracture morphology is characterized by quasi-cleavage fracture.关键词：Thixoforming;AZ63Magnesium Alloy;Aging Time;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：Characteristics of primary phases in semi-solid A356 aluminum alloy was analyzed using multifractal theory,and the multi-fractal dimension spectrum was calculated.The results show that the primary phase in semi-solid A356 aluminum alloy exhibits multi-fractal characteristics.When helix angle in helical curve duct is 540°,the spectral width（Δα）of multi-fractal spectrum is the narrowest in the four groups of helix angle tests,and the distribution of primary phase is the most uniform.When pouring temperature is 635 ℃,the spectral width（Δα）of multi-fractal spectrum is the narrowest in the four groups of pouring temperature tests,and the distribution of primary phase is the most uniform and concentration.All morphology of spectral function f（α）is hooked to the left because of all spectral function symmetryΔfof eight group tests more than 0,and high probability subset is dominant.Parameters of multi-fractal dimension spectrum such as spectral widthΔα,spectral function symmetryΔfand spectrum function f（α）can be characterized by the quantificational dissimilarity of uniformity,which can describe the characteristics of semi-solid microstructure from a new point of view.关键词：Helical Curve Duct;Slurry;Microstructure;Multi-fractal
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发布时间：2023-12-18 - 摘要：Based on the analysis of structural characteristics of the magnesium alloy gearbox cover,the gating system,exhausting system,cooling system and core-pulling mechanism of magnesium alloy diecasting molds were described.Process parameters were optimized and applied to produce qualified products.The practical production exhibits the feasibility of mold design and processing parameter selection.关键词：Magnesium Alloy;Gearbox Cover;Die Casting Die;Process Analysis
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发布时间：2023-12-18 - 摘要：There exist problems in the practical die casting aluminum alloy disc parts,such as pin hole,cold spots,flowing mark and large plain deformation.A new die-casting die based on the analysis of die casting process was designed.According to the structural characteristics,uniform multi-rod and flat connecting groove were designed and inner gate with a larger area and width was used.The process of slow casting with rapid high pressure and pressure holding was also applied.The practical production shows that the improved scheme can reduce the casting defects effectively and improve production qualification rate.关键词：Disc Parts;Die Casting;Aluminum Alloy;Die
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发布时间：2023-12-18 - 摘要：The materials and its heat treatment of die casting plunger were introduced including four kinds of high strength tool steel and three kinds of heat treatment process.Surface treatment process such as surface nitrodizing,laser surface treatment and CVD were described.Progress in modifying structure design of die casting plunger was analyzed.Application and prospect of bionic technology in die casting plunger were expounded.In addition,the future development of materials and structure design of die casting plunger was presented.关键词：Die Casting Plunger;Material;Structure;Technology;Development Direction
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发布时间：2023-12-18 - 摘要：According to the structural characteristics of transmission extension box,large assembly datum plane was selected as parting surface.On the basis of forming part of the segmentation,two sets of independent core-pulling structure were designed.And the detailed casting and overflow system layout were presented.关键词：Die Casting Mould;Auto Transmission;Core-Pulling Mechanism;Casting and Overflow System
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发布时间：2023-12-18 - 摘要：A new developed automatic continuous wax-treatment apparatus was used to remove water and solid particles from middle temperature wax 162.The test results show that the quality of wax treated by the new apparatus is improved significantly,and its water content is less than 0.06%,and ash content is less than 0.04%.The operation cost of the new apparatus is less than 10% of electric cost of the old process.关键词：Wax Treatment;Middle Temperature Wax;Wax Quality
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发布时间：2023-12-18 - 摘要：Comparing with the traditional processing way,the car foam mold were produced with lower surface roughness,double dimensional accuracy using new equipment and technology.After optimizing and determining the final casting process with using the casting simulation software,burning foam before pouring metal process was carried out on the production of more complex automotive panel die castings.The automotive punching die castings with good quality were successfully produced combining with the vibration crystallization process.After tested,the dimensional accuracy is high,without carburization in surface,and the relevant internal defects was carried out in machining areas.关键词：Punching Die Steel Castings;Precision Machining;Burning Foam before Pouring Metal Process;Vibration Crystallization
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发布时间：2023-12-18 - 摘要：A series of matrix composites reinforced by tungsten carbide particles with different sizes were fabricated by spark plasma sintering（SPS）technology combined with interface remelting process in a vacuum tube furnace to investigate thermal fatigue performance of the surface composites prepared,focusing on effects of interface,particles distribution and matrix in the composite for thermal fatigue behavior.The results show that thermal fatigue performance of the composites with pearlite at surface layer is supperior to those of the composites with ferrite matrix.The distribution of particles is related with the thermal fatigue performance of composites observably.The composites with a row of particles distributed at the edge exhibit the smaller crack propagation rate.The interface is directly related with the thermal fatigue performance of the composites prepared.关键词：Surface Composites;Thermal Fatigue;Microstructure;SPS;Particles Distribution
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发布时间：2023-12-18 - 摘要：Polymer-coated molybdenum powders for selective laser sintering（SLS）process were produced,and green parts were manufactured by SLS.After the prototyping parts were post-treated in the vacuum furnace,the desirable parameters with polymer removal,pre-sintering and infiltration were presented.The infiltration parts with satisfied mechanical properties were produced successfully.The microstructure and mechanical properties of the infiltration parts were analyzed.The results reveal that the properties of the parts prepared are improved greatly,where the parameters,such as the porosity,the density,tensile strength,the elongation and compact toughness reach 3.2%,9.68g·cm-3,480490 MPa,12.1%12.7% and 14.114.8kJ·m-2,respectively.关键词：Polymer-coated Molybdenum Powders;Selective Laser Sintering（SLS）;Infiltration;Property
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发布时间：2023-12-18 - 摘要：Fe-Cr-Ni porous preform reinforced aluminium composites were produced by squeeze casting.After T6 heat treatment,tensile test was carried out to obtain the mechanical properties of the composites at room temperature and at 350 ℃.Fracture analysis was conducted by SEM and EDS,and the results reveal that,at room temperature,the fracture mainly occurrs in aluminium matrix,while at 350℃,the fracture is formed at the interface of reinforced particle and aluminium matrix.The compression performance of the composites were tested by using the Gleeble 3500thermo-mechanical simulation machine at room temperature with strain rates of 0.001,0.1and 10s-1.And the results indicate that,the yield stress is increased with the increase of strain rate.However,the peak stress nearly keeps constant at the test strains rates.During the compression experiment process,all the samples were cracked.The fracture induced by shearing stress has an angle of 45°with the axial direction of the sample.关键词：Squeeze Casting;Preform;Composites;Mechanical Performance
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发布时间：2023-12-18 - 摘要：SiCpreinforced pre-alloyed 6061 Al composites were prepared by powder metallurgy and hotpressing sintering.Effects of SiCpcontent on baking hardening and corrosion properties of the SiCp/6061 Al composites were investigated using optical microscope,scanning electron microscope,Vicker hardness,tensile testing and electrochemical test.The results show that the baking hardening and corrosion resistance of the SiCp/6061 Al composites are related closely with the volume fraction of SiC particles.When the volume fraction of SiC particles is 20%,the tensile strength of SiCp/6061 Al composite is improved obviously,while the elongation and corrosion resistance are decreased.关键词：SiCp/6061Al Composites;Baking Hardening;Mechanical Properties;Corrosion Properties
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发布时间：2023-12-18 - 摘要：Influences of different power（0900 W）and treating time（0120s）of ultrasonic on solidified structure and mechanical properties of Mg97Y2Cu1 alloy reinforced by long-period ordered structure were described.The results show that solidified structure and mechanical properties of the alloy can be improved by ultrasonic melt-treatment.The second phase is transformed from continuous network into uniform dispersion particles.With the increase of ultrasonic power or treating time,primary grain in the alloy is refined at first and then coarsened,and primary phase exhibits desirable with 700 Wfor 60 s.With the ultrasonic power of 700 Wfor 60s,tensile strength and elongation of the alloy are increased by23.8% and by 105%,respectively,compared with those of the alloy under traditional condition.关键词：Ultrasonic;Long-period Ordered Structure;Mg97Y2Cu1 Alloy;Solidified Structure;Mechani-cal Properties
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发布时间：2023-12-18 - 摘要：The centrifugal casting process of graphite mould for a titanium alloy baseboard used for a chemical equipment was introduced.And origination of shrinkage porosity in the castings was analyzed.By increasing the centrifugal rotational speed and changing riser position,such as the centrifugal rotational speed increased from 150r/min to 220r/min,the original overhead vertical riser biased 60 mm along radial direction,shrinkage porosity in the baseboard was eliminated.For the large baseboard castings including stiffened plate,some measures were adopted,such as pouring gate with fully convered the stiffened plate,using gravity for stiffened plate feeding,and with help of the combined action of centrifugal force and gravity to realize the complete filling of 3mm reinforced plate,the qualified titanium alloy baseboard castings were produced finally.
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发布时间：2023-12-18 - 摘要：The microstructure and mechanical properties of Al-6.5Mg alloy under as-cast and annealed state conditions were investigated by OM,SEM,EDS,tensile testing machine and JMat-Pro software.The results reveal that the grain size of the as-cast alloy reaches 90μm,and the average tensile strength,yield strength,elongation and section shrinkage reach 228 MPa,131.7 MPa,31.9% and 39%,respectively.Meanwhile,fracture morphology is characterized by the typical dimple fracture.After annealing at 500 ℃ and 520 ℃for 24 h,respectively,the yield strength,elongation and section shrinkage exhibit stable,however,the tensile strength is improved by 23.2% and by 24.2%,respectively,reaching 281 MPa and 283 MPa.In addition,the fracture morphology is still presented as the dimple fracture.Driving by the thermodynamics in the annealing process,the EDS scanning atomic percentage of Mg element distributed in the grain interior and grain boundary are increased slightly.关键词：Aluminum-Magnesium Alloy;Mechanical Properties;Microstructure;Material Simulation
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发布时间：2023-12-18 - 摘要：For difficult detection of dim target in magnesium alloy melt images,a detection method based on support vector machine regression（SVR）was proposed.At first,the function approximation characteristic of SVR theory was utilized to estimate background of original images.Then the two reconstructed images were obtained and the operation of frame difference was used for the two reconstructed images.At last,the dim target was recognized by using threshold segmentation proposed and morphological opening operation.Compared with algorithm of BP neural network background prediction,the frame difference image obtained in algorithm proposed is improved by 17.67% and by 17.69%,respectively,in signal to noise ratio（SNR）and SNR gain,and the algorithm also exhibits an advantage in real-time.关键词：Magnesium Alloy Melt;First Bubble;Support Vector Machine Regression;Background Pre-diction;Threshold Segmentation
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发布时间：2023-12-18 - 摘要：The base tube is made of oxygen-free copper with a complex inner cavity,so traditional machining and electrolytic machining can’t meet the requirements of efficiency and excellent product quality.According to the special structure,single pass cold extrusion forming with a hollow tube was adopted after the comparative analysis.Based on calculating the dimensional size,deformation rate and extruding force,the suitable forming equipment,the die size design and die structure design were conducted.关键词：Base Tube;Cold Extrusion;Die;Design
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发布时间：2023-12-18 - 摘要：ф16mm Cu-Ag alloy rod billets with different Ag content were prepared by horizontal continuous directional solidification method.The Cu-Ag alloy wire with 0.12 mm in diameter was produced with many passes of cold drawing.The mechanical properties and electrical conductivity of Cu-Ag wires were tested.Effects of Ag content and drawing deformation on the tensile strength,elongation and electric conductivity of Cu-Ag wires were examined.The results show that the directional solidification rod billet exhibits continuous columnar crystal textures along the longitudinal direction,which results in excellent elongation performance.Therefore,it is very suitable for drawing fine wires.Finally,wires’ elongation is increased by the recystallization annealing processing.Cu-Ag alloy fine wires with 58.00MS/m conductivity,300 MPa strength and 23% elongation were produced successfully.关键词：Cu-Ag Alloy Fine Wires;Directional Solidification;Drawing Deformation;Tensile Strength;Electrical Conductivity
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发布时间：2023-12-18 - 摘要：<正>20150801 Shabestari S G,Saghafian H,Sahihi F,et al.斜板铸造与半固态成形制备Al-25Mg2Si复合材料微观组织研究.International Journal of Cast Metals Research,2015,28（3）:158-166.半固态金属加工能够制造形状复杂、近净成形、力学性能良好和尺寸公差精度高的零件。与传统铸造相比,半固态成形有很多优势,如降低宏观偏析、凝固收缩、降低成形温度等。研究了冷却斜板铸造的半固态成形对Al-Mg2Si复合材料微观组织的影响。首先使用热分析方法绘制了复合材料的冷却曲线,通
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发布时间：2023-12-18
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