最新刊期
卷 29 ， 期 11 ， 2009
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- 摘要：The Mg-5Zn-1Y-0.6Zr alloys were prepared by rapidly solidified method.Solidification structure and properties of the prepared alloy were investigated by XRD,SEM,HRTEM and micro-hardness measurements.Microstructure of the alloy is composed of fine α-Mg phase,amorphous phases and I-Mg3Zn6Y quasicrystal phase discontinuously distributes along crystal boundary.Based on the heat transfer theory,the cooling rate of the alloy ribbons can be calculated by one-dimensional heat conductivity equation.With the increase of cooling rate,grain size in the microstructure of the alloy is refined with the more homogeneous distribution of composition,and the volumetric fractions of amorphous phase are raised,meanwhile,micro-hardness value of the alloy is increased greatly,and the maximum value reaches Hv 167,which is 2.2 times of that of the conventionally solidified alloy.关键词：Cooling Rate;Rapid Solidification;Mg-5Zn-1Y-0.6Zr Alloy;Microstructure
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发布时间：2023-12-18 - 摘要：The Mg2Si/Al-Si composites were prepared by direct melt reaction（DMR）.Effects of pouring temperature and cooling rates on microstructure and mechanical properties of the composites were investigated.The results show that Mg2Si particle and primary Si phase in the composites become fine and uniform with pouring at 750℃,and the mechanical properties of the composites are improved.The mechanical properties are greatly deteriorated as a result of the coarseness of Mg2Si particle and primary Si phase in the composites with pouring at an under-lower or over-higher temperature.Meanwhile,with increasing in cooling rates,the mechanical properties of the composites are obviously improved.
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发布时间：2023-12-18 - 摘要：Dynamic globularization behavior of lamellar structure in the TA15 alloy was examined by isothermal constant strain rate compression testing on thermal simulator with strain rate of 10-3～1 s-1 and true strain of 0.22～0.92 at 900 and at 950℃.The results reveal that with increasing true strain from 0.22 to 0.92,the globularization rate of alpha phase is increased by 40%,showing obvious effects of true strain on dynamic globularization.At a given true strain and strain rates,globularization rate of alpha phase exhibits slight difference with deformation at 900℃ and at 950℃,keeping in range of-7%～7%.When strain rate is in range of 10-3～10-1 s-1,with decreasing in strain rate,globularization rate of lamellar alpha phase is greatly improved,while strain rate is more than 10-1 s-1,globularization rate is nearly independent of the change of strain rate.True strain-true stress curves of TA15 alloy are characterized by flow softening at different strain rates and temperatures,which is attributed to the dynamic globularization and kinking of lamellar alpha phase.关键词：TA15 Alloy;Lamellar Al Phase;Dynamic Globularization;Thermomechanical Parameters
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发布时间：2023-12-18 - 摘要：Softening and recrystallization of Cu-Ag alloy for Cu cladding Al contact wire were analyzed by hardness testing,microstructure and static recrystallization kinetics.The results indicate that softening temperature of the Cu-Ag alloy is approximately 390℃,and recrystallization temperature is in range of 350～450 ℃.Activation energy of recrystallization is calculated to be 77.68kJ/mol during annealing process.Completed time of recrystallization makes about 414.4,167.7 min with annealing at 350 ℃ and at 390℃.关键词：Cu Cladding Al Contact Wire;Cu-Ag Alloy;Annealing;Softening Temperature;Recrystallization
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发布时间：2023-12-18 -
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- 摘要：Effects of segregation defects in the practical produced ZL205A castings on mechanical properties,fracture morphology,composition and molten temperature were analyzed by SEM（scanning electron microscope）,EDS（energy dispersive spectrometer） and DSC.It is found that segregation defects have the obvious effects on mechanical properties of the alloy castings.As the grades of segregation defects increase,the trend is decreased for the tensile strength which is more than 360 MPa,the yield strength which is all more than 280 MPa changes slightly,and the elongation is quickly decreased,which is almost lower than 4%,and all micro-hardness values are higher than 100.The fracture mechanism of the samples with defects free is characterized by ductile fracture while that of one with segregation is characterized by inter-crystalline brittle fracture.The substrate composition is mainly composed of α-Al solid solution with undissolved Al2Cu phase distributed along grain boundary.Melting temperature of eutectic phase Al2Cu reaches 544℃ and melting temperature of α-Al solid solution phase is in range of 625～640℃.The cards of segregation defect grades have been presented based on property testing results.关键词：Segregation;ZL205A;Aluminum Alloy;Casting;Property
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发布时间：2023-12-18 - 摘要：In-situ WC particle was synthesized with tungsten wire and carbon atom cluster in the gray cast iron molten in electromagnetic field.The particles synthesized were distributed around the residual tungsten wire,where a clear diffusion zone was formed.The electromagnetic field can accelerate mass transfer processes in the molten,which is beneficial for the quick formation of a series of small Fe-W-C ternary zones containing high tungsten concentration around the tungsten wires and the improvement of the kinetic condition of in-situ WC.However,the gap of the inter-particles can restrain the diffusive rates of elements.关键词：In-situ Synthesis;Tungsten Wires;WC;Electromagnetic Field
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发布时间：2023-12-18 - 摘要：Alloying coating with wear resistance,corrosion resistance,anti-high temperature was prepared on the surface of ductile iron using sub-micron TiC and CrxCy alloy mixed powder as raw materials by the laser alloying method.Constituent and microstructure of the alloying coating were analyzed by XRD,SEM,EDS,and micro-hardness was examined,and wear resistance was tested in condition of dry friction at room temperature.The results reveal that alloying coating with compact structure is 930 HV in micro-hardness and is 1/16 of ductile iron in wear rate in condition of dry sliding friction,showing the improvement of wear resistance of alloying coating.关键词：Ductile Iron;Laser Alloying;Microstructure;Micro-Hardness;Wear Resistance
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发布时间：2023-12-18 - 摘要：Precipitation of MgZn2 phase in B93 forgings during aging process was characterized by qualitative optical microscope（OM） observation,X-ray diffraction（XRD） and precision measurement of lattice constant,and precipitation of second phase in the alloy during aging process was described by examining the change of resistivity of B93 alloy during continuous heating process and delayed time process.The results reveal that resistivity of the alloy varies with changing in temperature during continuous heating process as a result of different precipitation rate of precipitates in the alloy at different temperatures.At a given holding temperature,with increasing in holing time,resistivity is decreased,and it keeps a constant value after complete precipitation.With increasing in aging temperature,resistivity is increased and descending rate of the resistivity curves is quickened,so the time to reach the constant value becomes shorter.Meanwhile,a calculation formula for resistivity is presented based on the curves of resistivity to temperature.关键词：Continuous Heating;XRD;Lattice Constant;Resistivity
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发布时间：2023-12-18 - 摘要：Mathematical model and its solved method for liquid filling and solidification simulation were presented.Based on the mathematical model and its solved method,velocity field,temperature field and pressure field of hard disk base during die casting were visualized by the Magma software.Combined with simulated result,the origination of shrinkage porosity and gas hole in the hard disk base was described.Through simulation optimization,the method eliminating defects was presented.Practical production verifies that the simulated results are desirable and optimized result is feasible.关键词：Numerical Simulation;Filling and Solidification;Die Casting;Process Optimization;Hard Disk Base
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发布时间：2023-12-18 - 摘要：3D CAD mould was designed based on Pro/E,and processing simulation analysis,defects prediction and processing design optimization were performed by the Anycasting software.Then mould design was completed by the Pro/E,and CAM was conducted directly,which could greatly shorten the developing period of new product and improve the reliability of design.关键词：Pro/E;Casting Mould;CAD/CAE/CAM Design
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发布时间：2023-12-18 - 摘要：Dendritic growth in Al-2.5Cu alloy during isothermal solidification was simulated by phase field model coupling solute field with flow field to understand effects of forced convection,noise intensity and anisotropic on dendritic morphology.The results indicate that dendrite is grown asymmetrically in condition of forced convection,where the growth velocity of upstream dendrite is faster than that of downstream dendrite.Due to the effects of convection,the solute will be washed from upstream to downstream,resulting in the upstream concentration lower than the downstream one in the liquid alloy.With increasing in noise intensity,secondary dendrite arm in upstream direction becomes more and more developed as a result of the increase of lateral branch.Meanwhile,with rising in anisotropic value,the growth velocity of dendritic tip is promoted with decreasing in curvature radius.关键词：Phase Field Method;Forced Convection;Anisotropic;Noise Intensity
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发布时间：2023-12-18 -
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- 摘要：Semi-solid slurry of AZ91D magnesium alloy was prepared by rotary pouring method,and rheo-rolling experiment was carried out on a horizontal twin-roll caster,furthermore,the microstructure of the alloy before and after rheo-rolling process was analyzed comparatively.The results show that primary phase becomes more rounds after rheo-rolling process.Desirable spheroidization can be observed in the rheo-rolled AZ91D magnesium alloy with pouring at 620℃ and holding for a short time.Average grain size of primary phase is slightly decreased with more homogeneous distribution in the rheo-rolled AZ91D magnesium alloy.Grain density of primary phase in the rheo-rolled AZ91D magnesium alloy sheet surface is less than that in semi-solid slurry.Furthermore,grain density is significantly reduced in the alloy with pouring at 620 ℃ after rheo-rolling.关键词：Rheo-rolling;Semi-solid;Magnesium Alloy
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发布时间：2023-12-18 - 摘要：By means of tensile testing machine,metalloscope and equal channel angular extrusion（ECAE） testing,preparation of Mg-Al magnesium alloy semi-solid billets and its thixo-extrusion forming were investigated.The results show that desirable strain induced effects can be obtained by ECAE.After Mg-Al magnesium alloy was processed by ECAE,mechanical properties was increased with the refinement of grain size.Semi-solid billets prepared by new SIMA were characterized by fine grains,desirable spheroidization and homogeneous microstructure.In contrast,semi-solid billets prepared by direct isothermal treatment were characterized by coarse grain and terrible spheroidization.High mechanical properties and fine grains occur in angle frame components manufacture by thixo-extruding new SIMA prepared Mg-Al series semi-solid billets including AZ61,AZ80,AZ91D and AM60.Tensile strengthes of angle frame components reach 306.8,308.3,299.8 and 321.6MPa,respectively,and elongations are 21.6%,28.4%,14.6% and 29.6%,respectively.关键词：ECAE;Mg-Al Series Magnesium Alloy;Semi-solid Billets;Thixo-extrusion
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发布时间：2023-12-18 - 摘要：Thermal cycling of die casting die for aluminum alloy speed governor cover was simulated by the ProCAST software.The simulated results indicate that temperature in the die during steady operation stage and temperature during castings-picked out exhibit higher.Cycling parameters were optimized from 60 s per cycling period to 80 s per cycling period by thermal cycling simulation.It is found that the maximum temperature in the die during steady operation stage is decreased from 340℃ to below 300℃,decreased by approximately 20℃ in average temperature,and both die operation temperature and castings-picked-out temperature are decreased to a desirable temperature range.The simulated results are well in agreement with practical ones.关键词：Die Casting Die;Thermal Cycling;Numerical Simulation;ProCAST Software
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发布时间：2023-12-18 - 摘要：Aluminum alloy port cover was manufactured by counter-pressure casting,and filling and solidification were simulated.The results reveal that the simulated results are accordant with the trial product ones.The mechanical properties of the trial-product aluminum alloy port cover with shrinkage porosity（hole） free,which is manufactured by pressure-reduction types counter pressure casting,are greatly improved,where tensile strength and elongation reach 315～325 MPa and 4%～6%,respectively.关键词：Counter Pressure Casting;Port Cover;Simulation;Mould Design;Processing Parameters
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发布时间：2023-12-18 - 摘要：Aiming at a die casting large complicated aluminum alloy power parts,some technological ways including improving flow types and optimizing vacuum exhausting structure are employed to significantly reduce the gas-entrapment defects in the parts on the basis of understanding flow and filling process of liquid aluminum alloy by numerical simulation and physical examination.Meanwhile,shrinkage porosity（hole） in the parts is eliminated by adopting movable insert,local pressurization and exact control for die temperature.Through above technological ways,both the appearance and quality of the parts can meet the designing requirements,realizing volumetric-production in a short time.关键词：Gas Hole;Numerical Simulation;Physical Examination;Large Complicated Aluminum Alloy Parts;Vacuum Die Casting
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发布时间：2023-12-18 - 摘要：7075 aluminum alloy axle body of hollow transmission shaft was prepared by squeezing casting,and the microstructure and mechanical properties of the axle body were described.The results reveal that squeezing casting high strength aluminum alloy tube with compact structure,fine grain size and excellent mechanical properties can be prepared with increasing in pressure at pouring temperature of 700℃ and mould temperature of 250℃.With pressure of 160MPa,microstructure of the tube is characterized by mixed morphology of dendrite,particle and rosette structure,meanwhile,tensile strength and elongation reach up to 545MPa and 8%,respectively.Fracture observation reveals that with increasing in pressure,fracture mechanism of 7075 aluminum alloy is characterized by from cleavage crack to ductile crack.关键词：Hollow Transmission Shaft;Squeezing Casting;7075 Aluminum Alloy
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发布时间：2023-12-18 - 摘要：Zr-based ceramic mold with surface crack free was prepared by the colloidal pouring forming technology and vacuum drying method.Vacuum drying parameters for ceramic mold were optimized by statistical experiment design.Vacuum,vacuum drying temperature and vacuum drying time influencing the processing were investigated by single factor experiment.The optimized processing parameters were presented by the Box-Behnken design.The drying shrinkage rate and compressive strength of the ceramic mold reach 0.686%,6.39MPa with 0.06MPa at 81℃ for 5 hours.关键词：Vacuum Drying;Box-behnken Design;Response Surface Analysis;Shrinkage Rate;Compressive Strength
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发布时间：2023-12-18 -
- 摘要：The origination of generated mechanical burning-on in blind and tenuous hole in negative pressure lost foam casting were expounded theoretically.A way to prevent mechanical burning-on was presented including using proportional CaCO3 as coating and filler to coat and fill into the hole.The results are verified.关键词：Negative Pressure Casting;Tenuous Hole;Burning-on
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发布时间：2023-12-18 - 摘要：2E12 aluminum alloy continuous casting ingots were prepared by electromagnetic casting and direct chilling casting,respectively.Through comparatively analyzing microstructure and mechanical properties of two kinds of ingots,effects of electromagnetic field on continuous casting process and properties of 2E12 aluminum alloy ingots were investigated.The results reveal that electromagnetic continuous casting 2E12 aluminum alloy ingot exhibits excellent surface quality and microstructure as well as desirable mechanical properties.Compared with those of direct chilling casting ones,the average grain size is decreased from 58 μm to 36 μm,tensile strength and elongation of electromagnetic continuous casting 2E12 ingot are increased by 9.08% and by 61.58%,respectively.In addition,fracture mechanism of the EMC ingot is characterized by quasi-cleavage crack.关键词：2E12 Aluminum Alloy;Electromagnetic Casting;Direct Chilling Casting;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Thermal deformation behavior of Al2O3 particulate reinforced aluminum matrix composites fabricated and pure Al were tested by compression with the Gleeble-1500 thermal simulator at different deformation temperature and different deformation rates.The results show that the flow stress is increased with decreasing in deformation temperature and increasing in deformation rates.Al matrix composites were greatly strengthened by Al2O3 particulate as a result of restraining dynamic recrystallization in the composites.关键词：Al2O3 Particle;Al Matrix Composites;Stress-strain Curves;Thermal Deformation
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发布时间：2023-12-18 - 摘要：Pb cladding Sn bimetal composite rods with 8 mm in inner diameter and 12 mm in outer diameter were prepared with self-developed equipment by air-pressing push-out core filled continuous casting.The appearance,fracture morphology and interface of the composite rod were observed by OM（optical microscope）.The results show that continuous stable composite rods exhibit desirable surface quality and uniform cladding thickness as well as metallurgical bonding in interface.关键词：Composite Rod;Air Pressing Push-out;Core Filled Continuous Casting;Bimetal
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发布时间：2023-12-18 - 摘要：Microstructure,thermal stability and mechanical properties of spray-deposited prepared Al-17Si-4Fe-2Mn-3Ni-3.5Cu-1Mg alloy were investigated by OM（optical microscope）,XRD（X-ray diffraction） and SEM（scanning electron microscope）.The results reveal that the microstructure of the alloy is composed of lots of dispersed granular phase,a little block-like phase and eutectic matrix.Obvious coarseness of primary Si phase can not be observed in the alloy with different heating time at 150℃,250℃ and 350℃,respectively,which verifies that the alloy exhibits desirable thermal stability at below 350℃.Ultimate tensile strength of the as-extruded alloy after T6 treatment reaches 373MPa at room temperature.关键词：Spray-deposition;Al-Si Alloy;Microstructure;Thermal Stability
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发布时间：2023-12-18 - 摘要：Elevated aging precipitation behaviors of permanent mould and sand mold casting Mg-Gd-Y-Zr alloys were observed by OM（optical microscope）,SEM（scanning electron microscope） and XRD（X-ray diffraction）.The results show that the T4 alloy aged at elevated temperatures is composed of α-Mg solid solution with（Gd+Y） phase and cuboidal particle and a little spheroidized Zr nuclei as well as β phase.Average grain size in the T4 alloy is nearly independent of the elevated aging treatment processes,however,with increasing in aging temperature and in aging time,hardness of the alloy is slowly decreased.In addition,the β phase distributed in trigonal and parallel orientation in the grain can be observed,and precipitates-free zone（PFZ） appears in the grain boundary.Distribution and orientation of precipitates in the alloy at elevated aging is independent of the forming conditions.关键词：Elevated Aging;β Phase;PFZ
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发布时间：2023-12-18 - 摘要：Ironing process for high strength Ti alloy was simulated by rigid-plastic FEM（finite element method）.The grid chart and the metal flow velocity chart in marked point were presented during ironing process.Through the analysis of the velocity change of every marked point,it is concluded that formation of sunken end face is attributed to the flow velocity change of surface metal of the billets relative to center metal.Based on above analysis,effects of conical face shape of cavity mould and frictional resistance on ironing process were described.关键词：Ti Alloy;Ironing Process;Metal Flow;Sunken End Face
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发布时间：2023-12-18 - 摘要：Tensile strength of as-cast 7005 aluminum alloy produced by electrolytic liquid Al was measured by means of room temperature tensile testing.Fracture morphology and longitudinal microstructure were observed by OM（optical microscope） and SEM（scanning electron microscope） as well as EPA（energy spectrum analysis）.The results indicate that tensile strength of as-cast 7005 alloy is distinctly dependent on the Fe,Si,H and Al2O3 inclusions in electrolytic liquid Al.Shrinkage porosity and inclusions in aluminum ingot are controlled by creation of H2 and Al2O3 inclusions in electrolytic liquid Al.The hard brittle coarse second phase,such as AlFeMnSi,Mg2Si phase,are formed by the reaction of impurity elements Fe,Si in electrolytic liquid Al with alloy elements Mn,Mg,which is distributed in grains and on the grain boundaries.The fracture of the samples is attributed to the co-action of inclusions,shrinkage porosity and brittle AlFeMnSi phases.Tensile fracture mechanism of as-cast 7005 aluminum alloy is characterized by dimple-quasi-cleavage features of trangranular model.关键词：7005 Aluminum Alloy;Electrolytic Liquid Al;Al2O3 Inclusion;Fracture Morphology
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发布时间：2023-12-18 - 摘要：Rapid surface alloying Al on the surface of AZ31 alloy by high current pulsed electronic beam was conducted,and microstructure of alloying layer on the surface was observed,meanwhile,corrosion resistance and wear resistance of the AZ31 magnesium alloy after and before alloying Al were examined.The results indicate that typical crater can be observed on the surface after HCPEB bombardment.Compared with that of initial sample,the relative wear resistance of the sample with accelerating voltage of 27kV and five times pulse is increased by 6 times.In addition,the corrosion resistance of AZ31 magnesium alloy after alloying Al is greatly improved in 5% NaCl solution.关键词：Magnesium Alloy;HCPEB;Surface Alloying;Wear Resistance;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：Effects of size of secondary phase particles on recrystallized structure in 3003 hot rolled aluminum foil were investigated by OM（optical microscope） and SEM（scanning electron microscope） and TEM（transmission electron microscope） at different annealed temperature and holding time.It is found that recrystallized grain size in the 3003 aluminum foil is decreased with increasing in annealed temperature.At a given annealed temperature,the recrytsallized grain size is nearly independent of the holding time when it is below 16 hours.An explanation was presented with the help of secondary phase size from the mechanism of particle stimulated nucleation,and it also provided a way to refine recrystallized structure.关键词：3003 Aluminum Foil;Recrystallized Grain;Secondary Phase;PSN
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发布时间：2023-12-18 -
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- 摘要：Pressure-resistant cast ZCuSn3Zn8Pb6Ni1FeCo alloy was developed by adding Fe and Co into ZCuSn3Zn8Pb6Ni1 matrix alloy,and effects of Fe and Co element on microstructure and properties of the alloy were investigated.The results reveal that,compared with that of ZCuSn3Zn8Pb6Ni1 matrix alloy,the microstructure of ZCuSn3Zn8Pb6Ni1FeCo alloy is basically composed of α-{Cu,Sn,Zn}phase and hard-brittle δ-Cu10Sn3 phase as well as single Pb precipitates also.In addition,there exist α-Fe phase and γ-Fe precipitates and CoCu2Sn,Fe3Co7,Fe4Zn9 strengthening phase which exhibits semi-coherent or coherent lattice orientation with the matrix in the ZCuSn3Zn8Pb6Ni1FeCo alloy.ZCuSn3Zn8Pb6Ni1 matrix alloy exhibits typical dendrite with average grain size of approximately 3 mm and tensile strength of 180～230 MPa,while ZCuSn3Zn8Pb6Ni1FeCo alloy exhibits equiaxed structure with average grain size of 20～60 μm and tensile strength of 400～450 MPa as well as elongation more than 20%.The macro-segregation of Tin which exists in CuSn3Zn8Pb6Ni1 matrix alloy is eliminated in the ZCuSn3Zn8Pb6Ni1FeCo alloy.关键词：Bronze;Pressure-resistant Alloy;Casting
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发布时间：2023-12-18 -
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