最新刊期
卷 35 ， 期 6 ， 2015
- 摘要：The cooling curve of 6061 alloy was determined by analysis software,and primary solid fraction was tested at different temperatures.Using H1F100 servo press and cup type test mold,the 6061 semisolid alloy rheological casting-forging forming was carried out.Influences of parameters,such as alloy temperature,forming pressure,upper mould temperature,holding time,on the formability of semi-solid 6061 alloy were researched.The influences of technological parameters and heat treatment on microstructure uniformity of rheological casting-forging semi-solid 6061 alloy were discussed.The results show that,the semi-solid casting and semi-solid forging as well semi-solid casting-forging are feasible within a set of mold.The uniform microstructure in the alloy can be obtained at 645℃,the upper mould temperature of 300 ℃,the down mould temperature of 350 ℃,forming specific pressure of 105 MPa,and duration 0sto 4s.关键词：Semi-solid;Rheological Casting-forging;Forming Process;6061 Alloy;Microstructure Uni-formity
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发布时间：2023-12-18 - 摘要：Cu/SiC mixed powder with different mixture ratio was prepared by the high-energy ball milling technology.Effects of ball milling time,ratio of ball to material and speed of ball milling on powder particle size were analyzed by orthogonal testing.Cladding effect of powder was analyzed by EDS.The results show that effects of milling time on powder particle size are the dominant,and then rotational speed of ball milling,ratio of ball to material.With the increase of milling time,refining effect on powder becomes more obvious.With increasing in ball milling speed,the powder particle size can be refined.In addition,with the decrease of ball to material ratio,powder particle size is decreased firstly and then increased.With the ball milling time of 20 h,ratio of ball to material of 20∶1and rotational speed of300r/min,powder particle size is the smallest.And cladding effect in the ball milling powder exhibits obvious.关键词：Ball Milling;Process Parameter;Particle Size
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发布时间：2023-12-18 - 摘要：At 500 ℃for 1 000 h,the compatibility between 45# carbon steel or 304（18Cr9Ni）stainless steel and Mg-15Ca-15 Zn phase change heat storage alloy was analyzed.The corrosion ability of steel samples was evaluated by weight-loss method,and the corrosion layers and their elements were analyzed by EPMA.The results show that the molten Mg alloy has a little corrosion to steel container materials,and the corrosion process is controlled mainly by the diffusion of Mg atoms.Cr can be segregated at the grain boundary,preventing effectively the diffusion of the Mg atoms,therefore,the corrosion resistance of 304 stainless steel in molten magnesium alloy is superior to that of 45# carbon steel.关键词：Mg-based Alloy;Phase Change Heat Storage Material;Container Material;Compatibility
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发布时间：2023-12-18 - 摘要：GASAR porous Cu-1.3Cr alloys were fabricated by a metal/hydrogen unidirectional solidification method under a hydrogen pressure of 0.1,0.2,0.4,0.5and 0.6MPa.Effects of hydrogen pressures on pore structure and distribution of GASAR porous Cu-1.3Cr alloys were analyzed.The results reveal that at pure hydrogen atmosphere,with increasing in hydrogen atmosphere,the porosity tends to firstly increase and then decrease,and the average pore diameter tends to decrease.Meanwhile,the uniformity of pore size,spatial distribution of pores and pore-cells are increased with hydrogen pressure increase,which are attributed to the increase of gas density and narrow of distribution range of pore size as well as decrease of pore distance.关键词：GASAR;Porous Cu-1.3Cr Alloy;Hydrogen Pressure;Porosity;Average Pore Diameter
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发布时间：2023-12-18 - 摘要：Through an analysis of the solidification and rheologic behavior,some design rules and their mathematic expression were presented about some key parameters,such as compacting pressure,holding pressure time,pouring volume and pressing force,in the squeeze casting process,or molten metal die forging process（MMDF for short）.The compacting pressure in the process must be more than the sum of the resistant flowing stress of the alloy and the resistant stress along the feeding channels,or the feeding range should be larger than the distant from the pressing palace to the hot spot of the workpiece;or the available pressure at the final solidification position is more than zero in the whole pressing period,if not,shrinkage defects could be observed.The holding pressure time should be larger than the solidification time in the final solidification position,if not,shrinkage cavity or crack easily occurs.The pouring volume should be larger than the sum volume of the workpiece and the technique remainder,and smaller than the valid volume of the pressing chamber,if not,misrun can be observed.The pressing force has to be large enough to make the solidificated alloy flow to feed the shrinkage,to make the workpiece compact and overcome the resistant force from the friction between the punch and the die,if not,misrun or shrinkage cavity could occur.The validity of these rules has been proved by many facts of aluminum alloy and iron and steel.关键词：Squeeze Casting;Technique Parameter;Design Rule
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发布时间：2023-12-18 - 摘要：The characteristics,application prospects and research status of porous magnesium alloys were described.Meanwhile,the existing problems and future development of porous magnesium alloys were also presented.关键词：Porous Magnesium Alloys;Research Status;Problems and Future Development
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发布时间：2023-12-18 - 摘要：Based on a cellular automaton（CA）-finite element（FE）model in the ProCast,a model for analyzing microstructure of twin roll thin strip casting was established for high silicon electrical steel with6.5%Si content.Influences of superheat,roll casting speed,heat transfer coefficient on thin strip solidification microstructure were described.The results reveal that with increasing in pouring temperature,grain size is coarsened with the increase of columnar grain content.Excessive superheating degree of liquid steel can narrow the solidification zone,which can play possible liquid-steel leakage.With increasing in roll-casting speed,the grain size is refined with the decrease of columnar grain content.A lower rollcasting speed easily takes the roll-casting accident,while a higher roll-casting speed can lead to the possible liquid steel leakage.As the increase of heat transfer coefficient,grain size and columnar grain content are increased.关键词：Twin-roll Casting;Microstructure;CA-FE;Numerical Modeling
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发布时间：2023-12-18 - 摘要：In the structural design of gating system,crucible was designed into two cavities,and two cavities were connected by apipeline,and pipeline was flown from the left bottom center of the cavity to the right wall of the chamber in tangential direction into the right cavity to achieve the self-stirring effect.The flow field in stirring crucible and in traditional crucible was simulated,respectively,by the ANSYS12/Fluent.The results show that the stirring crucible can realize the better function of the mixing,greatly improving the temperature,composition of liquid and degree of uniform distribution.关键词：Crucible;Self-stirring;Numerical Simulation
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发布时间：2023-12-18 - 摘要：Aiming at the problem of heat load in high-silicon aluminum cylinder for high detonation pressure diesel,the mathematical models and boundary conditions between temperature and stress were established.The characteristic of heat load in the high-silicon aluminum cylinder at a given condition was described by calculating temperature field,thermal stress and strain fields through Ansys.The results reveal that in high-silicon aluminum cylinder,the overall temperature field is descended from top to bottom axially,and the maximum temperature occurs at the upper of inner wall of the cylinder.The thermal deformation is characterized by large deforming at upper with small deforming at lower.关键词：High-silicon Aluminum;Cylinder;Finite Element Analysis
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发布时间：2023-12-18 - 摘要：The semi-solid slurry of 6061 wrought aluminium was prepared by the self-inoculation method,and the microstructure of rheo-diecasting 6061 wrought aluminium alloy was observed.The results indicate that the finer,uniform and nearly spherical primaryα-Al phase can be observed in semi-solid slurry by self-inoculation method.The slurry is held at the semi-solid temperature for a short time,then rheodiecasting.When slurry is held at 640 ℃for 5min,the primaryα-Al phase in die-casting has a smaller grain size of 65.7μm and a better shape factor of 1.27,respectively.关键词：6061 Wrought Aluminium;Self-inoculation Method;Slurry Preparation;Rheo-diecasting
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发布时间：2023-12-18 - 摘要：Effects of alternating electromagnetic field on flow characteristics and microstructure of semisolid A356 alloy which was prepared by cooling slope method in a inclined tube with inner diameter in80mm×550mm was investigated by an induction field in the metal liquid as a result of the alternating electromagnetic field utilizing to mix the metal liquid.The results show that,the Lorentz force can compel the flow of metal liquid from straight line to sine curve,and the non-homogeneous nucleation of the tube wall is enhanced,meanwhile,nucleation rate of the first eutectic phase is increased significantly.While the magnetic field can enhance the convection inside the metal liquid,and restrain deep undercooling and large temperature gradient of the metal liquid,thus it can inhibit preference growth of the first eutectic phase.Under electromagnetic field,the first eutectic phase is refined and spheroidized obviously,and homogeneity of structure is improved significantly.关键词：Semi-solid;Alternating Electromagnetic Field;Cooling Slope Method;Inclined Tube;Alumi-num Alloy
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发布时间：2023-12-18 - 摘要：A typical thin-walled complex component was produced with ZL101 Acasting alloy.Based on the structure shape and casting difficulties analysis of the bracket casting,composite solidification process of investment shell mold combined with low-pressure casting was designed.The results reveal that by adding reinforcing rib and exhausting slot within wax pattern,adjusting step heating process parameters of investment shell mold,optimizing the technological parameters of low-pressure casting and the T6heat-treatment,combining with the design of quenching deformation revise and manufacturing benchmark,misrun and shrinkage porosities defects in the bracket casting could be eliminated successfully,obtaining the qualified bracket.关键词：Thin-walled Shaped Casting;ZL101A Casting Alloy;Investment Casting Shell;Low-pressure Casting
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发布时间：2023-12-18 - 摘要：Filling and defects distribution in the die casting aluminum alloy sump were predicted,and origination of the defects generation during trial mould and trial production process was described.The gating and exhausting system was modified based on result analysis,so the sump quality was improved with decrease of mould developing cycles.The results reveal that they are the key factors,such as rational pouring parameters and exhausting system as well allowance,for obtaining high quality aluminum alloy sump.关键词：Die-casting Aluminum Alloy Sump;Numerical Simulation;Gating System;Exhaust System
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发布时间：2023-12-18 - 摘要：Three processes of ingate used on one Kind of cluth housing die-casting dies were described,and advantages and disadvantages were expounded.关键词：Clutch Housing;Die-casting Die;Ingate;Production Efficiency
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发布时间：2023-12-18 - 摘要：The SiCp/6061 aluminum matrix composites with SiC particles in range of 20 to 50μm were prepared by semi-solid stirring casting.Effects of SiC particle size on the microstructure and properties of SiCp/6061 aluminum matrix composites were investigated.The results indicate that the dispersion uniformity of SiC particles in aluminum matrix composite is improved with increasing in SiC particle size,however,the tensile properties and elongation are decreased.Fracture mechanism of the composites is characterized by co-action of interfacial de-bonding and particle cracking.The particle crack plays a dominant role in crack mechanism with SiC particle size increase.With the increase of SiC particle size,wear resistance of SiCp/6061 aluminum matrix composites is increased.The friction and wear mechanism can be described by adhesive wear and abrasive particles wear,and the abrasive wear will play the dominant role with increasing in SiC particle size.关键词：Semi-solid Stirring Casting;SiC Particle;Aluminum Matrix Composites;Wear Properties
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发布时间：2023-12-18 - 摘要：Two passes reverse direction processing was carried out to the thermal sprayed Al2O3 and TiB2particles reinforced aluminum matrix coating on the aluminum alloy surface by frictional stirring processing（FSP）.The results show that after the friction stirring processing,the hole porosity between the original laminated and porous particles almost disappears as a result of the effect of strong pressure and high temperature,and the gap between coating and substrate is narrowed,so the microstructure of the coating become compact and dense after FSPed.After single direction friction stirring processing,coating internal stress is increased,leading to an increase of microhardness from 72 HV to 85 HV.After reverse direction frictional stirring processing,severe plastic deformations can be observed in the area where friction stirring processed dramatically,leading to microstructural evolution,so that the coating exhibits fiber-like flow line structure.The coating microhardness is increased greatly from 72 HV to 150 HV,which is two times higher than the original coating’s.关键词：Frictional Stirring Processing;Microstructure Evolution;Thermal Spraying Coating
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发布时间：2023-12-18 - 摘要：SiCp/2024 composite bars with SiC particle volume fraction of 5%,10%,15%,respectively,were prepared by powder mixing and semi-solid thixoextruding forming technology.Influences of vacuum treatment process and SiC particle volume fraction on microstructure and properties of the composites prepared were investigated.The result indicates that porosity rate is decreased approximately 65.3%in the composites prepared by vacuum treatment than that one without vacuum treatment,and the tensile strength is increased by 9.7%.With increasing in SiC particles volume fraction,tensile strength and hardness of the composites are increased,while the plasticity is decreased.The composites with15% SiCpare increased by 14.1%in tensile strength and decreased by 51.9%in elongation,compared with those of the composites with 5% SiCp.And with the increase of SiC volume fraction,brittle fracture exhibits more obvious.关键词：Semi-solid Thixoextruding;SiCp/2024 Composite;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Three dimensional network Al2O3/ZL102 porous ceramics composites were prepared by infiltration process.The porosity,permeability coefficient and carrying capacity of the samples were measured.The interface of metal/ceramics and the morphology of pore inside the ceramic skeleton were observed by SEM（scanning electron microscopy）.Effects of infiltration parameters on the porosity and permeability coefficient of the porous composites were investigated.The results indicate that the porosity is increased with the increase of ceramic preforms pore density,and decreased with increase of infiltration temperature and pressure.In addition,the permeability coefficient of porous materials is increased with porosity increase.With a higher permeability coefficient,the carrying capacity of the sample is increased accordingly.关键词：3D Network Ceramics;Porous Composites;Carrying Capacity
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发布时间：2023-12-18 - 摘要：Effects of pouring method on microstructure of ZL205 Aalloy in sand mold casting were investigated comparatively.The results show that,for low pressure casting,compared with gravity casting,grain size in the alloy is refined due to the solidification under pressure,and microporosity in the alloy castings is decreased significantly with density increase.In addition,the experiment also reveals that the as-cast grain is sensitive to chilling effect,where with increasing in cooling rate,grain size is decreased.For the conventional casting,as a result of the slow cooling rate at the later stage of solidification,θ-Al2 Cu phase may be precipitated in form of lamellar inα-Al matrix,affecting as-cast strength of ZL205 Aalloy.关键词：ZL205A Alloy;Low Pressure Casting;Microstructure;Gravity Casting
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发布时间：2023-12-18 - 摘要：Effects of Al-10 RE master alloy on the microstructure and mechanical properties of as-cast Al-20 Si alloy were investigated.The experimental results reveal that the as-casting microstructure of Al-20 Si alloy mainly consists ofα-Al matrix,primary Si,eutectic Si and acicular Al11RE3 phase with adding Al-10 RE master alloy.The morphology of primary Si in the hypereutectic Al-20 Si is transformed from bulky to small blocky and globular shape with the increase of the Al-10 RE addition.It is found that with addition of 1.5%Al-10 RE,the average grain size with dispersive and homogeneous distribution of primary Si can be observed.Meanwhile,the tensile strength,elongation and micro-hardness of as-cast Al-20 Si alloy are increases from 98 MPa to 117 MPa,from 9.7%to 11.0%,from 70.93 HV to 87.76 HV,respectively.The RE element can change the growth morphology of primary Si,and fine grain size and generation of acicular Al11RE3 improve greatly the mechanical properties of the alloy.关键词：Al-10RE Master Alloy;Al-20Si Alloy;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The microstructure and mechanical properties of as-cast Mg-Y alloys with different Y addition were investigated by means of optical microscopy,scanning electron microscopy,X-ray diffractometry and EDS as well as tensile testing.The results reveal that with increase of Y element,the microstructure of the alloy is changed from the singleα-Mg phase to the coexist phases of theα-Mg and Mg24Y5.The grain size in the alloy contained Y is refined with the Y content increased from 0.25% to 15%.With the increase of Y element,the tensile strength and hardness of Mg-Y are increased,while the elongation is decreased.关键词：Mg-Y Alloy;Microstructure;Mechanical Properties;Phase Composition
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发布时间：2023-12-18 - 摘要：By optical microscopy,SEM（scanning electron microscopy）,hardness and tensile testing,inside flange cracking failure of A356.2casting aluminum alloy wheel was analyzed.The results show that,the direct impact of the wheel can lead to deformation and a tiny crack,furthermore,during the long running,the tiny cracks can propagate inwardly to lead to the fatigue crack.And then,the cracking surface and the front extend depth will be oxidized constantly,accelerating cracking.关键词：A356.2 Aluminum Alloy;Wheel;Crack
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发布时间：2023-12-18 - 摘要：Effects of grain size and strain rate on ambient deformation behavior of hot rolled Mg-Al-Sn sheet with annealed at 250450 ℃ were investigated,and deformation mechanism was analyzed.The results reveal that with increasing in annealing temperature,the grain size in the alloy sheet is coarsened with a relative homogeneous distribution.With increasing in grain size,at a given strain,twin grain is increased.Meanwhile,with strain increase,twin grain in the alloy is increased too.With decreasing in strain rate,yield strength and tensile strength of the alloy are declined,while the elongation is increased.In addition,the volume fraction of twin grain is increased with increasing in strain.At the same strain,the volume fraction of twin grain in the alloy with strain rate of 0.01s-1 is the higher than that of ones with 10-4 s-1.关键词：Mg-Al-Sn Alloy;Grain Size;Strain Rate
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发布时间：2023-12-18 - 摘要：Effects of refining process,degassing,modification,roll-casting and heat treatment on microstructure and tensile properties of 8011 alloy were analyzed.It is found that after secondary refinery,the impurities are almost removed.Grains are refined with more homogenization after modification.Cold rolling strips are strengthened with decrease of elongation.Recrystallization treatment can improve the grain size and eliminate the working hardening effects.关键词：8011 Alloy;Roll-casting Strip;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：Effects of gravity filling method and low-pressure filling method on microstructure and properties of ZL114 Aaluminum alloy plate castings were analyzed through experiment and numerical simulation.The results show that mechanical properties of the ZL114 Aalloy plates in low pressure casting are superior to those of ones in gravity casting at the same condition in the melting process and heat treatment process,especially the elongation rate.During gravity filling process,the liquid metal is easy to form turbulence,which leads to the shrinkage porosity and gas hole in the plates as a result of bifilm wrapped in bubble involved in plates,and it is responsible for crack fracture.During gravity casting process,due to the adequate effective feeding pressure,obvious porosity defect exists in the ZL114 Aalloy plates,while during low pressure filling process,the liquid metal is filled smoothly,and absence of bifilm will be involved in casting,so obvious defects in the casting is absent.关键词：Aluminum Alloy Casting;Filling Method;Mechanical Property;Casting Defects
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发布时间：2023-12-18 - 摘要：The trial-manufacturing of the carrier was described,and origination of crack、cold-shut and misrun in the sand mold gravity casting was analyzed.Crack is resulted from complicated shape with unevern wall thickness,and the dis-rational processing design is responsible for cold-shut defects.Un-rational structure and processing design result in the misrun defects.Through adopting optimizing processing parameters,such as liquid aluminum alloy quality,pouring velocity,filling pressure,pouring time and exhausting channel,some defects,such as crack,cold shut,misrun,in the carrier,can be eliminated effectively.关键词：ZL205A Alloy;Long-thinned Carrier with More Cavities;Cast Method
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发布时间：2023-12-18 - 摘要：Influences of aging treatment process on microstructure and mechanical properties of Mg-Gd-YNd-Zr alloy were investigated by optical microscopy（OM）,scanning electron microscopy（SEM）,spectrometer and hardness tester.The results show that aging treatment can obviously improve the microstructure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy.Intermetallic compounds are precipitated homogeneously along grains,and the hardness is increased with increasing in aging temperature.However,if the aging temperature is too high or time too long,it can lead to over aging phenomenon,resulting in decrease of hardness of the alloy.The desirable aging heat treatment process is 200 ℃×16hafter solid solution treatment,where hardness value of the alloy reaches 73.38（HV）.关键词：Mg-Gd-Y-Nd-Zr Alloy;Microstructure;Vickers Hardness;Aging Treatment
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发布时间：2023-12-18 -
- 摘要：Based on the refinement and modification treatment of reclaimed brass melted straight by copper scrap,the research status of the covering agent,refining agent and modifiers for reclaimed brass,especially for reclaimed leaded brass,were summarized.The result shows that effective covering agent and refining agent for reclaimed leaded brass are absent recently,while the main modifiers are B,Ti,Zr,B-TiZr composite modifier,RE,Ca,P,et al.The fluxes for reclaimed leaded brass were also prospected.关键词：Copper Scrap;Reclaimed Brass;Refinement and Modification Treatment
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发布时间：2023-12-18 - 摘要：Hot compression deformation of Cu-Cr-Zr alloys at 0.000 10.100 0s-1 and 25700℃ was carried out on the Gleeble-3500 thermal simulation testing machine.The flow stresses-strain curves at different deformation conditions were investigated.The results show that the flow stress and peak stress are decreased with the increase of temperature and increased with the increase of strain rate,which indicates Cu-Cr-Zr alloy belongs to a kind of positive strain rate sensitive material.The stress increment rate and the flow stress of the alloy at rolling aging state are more than those of aging state at the initial stage,and with the increase of strain,flow stress of the alloy at rolling aging state is lower than those of ones at aging state.The flow stress of Cu-Cr-Zr alloy during high temperature deformation can be expressed in hyperbolic sine function.Meanwhile,the hot deformation activation energy of two states during hot deformation was calculated,and constitutive equation was derived.关键词：Cu-Cr-Zr Alloy;Hot-compression Deformation;Constitutive Equation;Flow Stress
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发布时间：2023-12-18 - 摘要：Through hardness test,optical microscope,scanning electron microscope and mechanical properties test,influence of deformation and heat treatment on microstructure and properties of micro alloying of Zn alloy were investigated.The results show that,with the increase of deformation rate,microhardness of Zn-2.1Cu-0.06 Ti alloy is increasesd firstly and then decreased.When the cold deformation rate reaches 70% microhardness has a maximum value,with the increase of Cu element content,the temperature resulting in the descrease of micro-hardness of Zn-Cu-Ti alloy is increased gradually.The Cu element within a certain range of addition can improve the micro-hardness and tensile strength of pure Zn,and increase of Ti element can improve the toughness of the alloy.关键词：Deformation;Heat Ttreatment;Zinc Alloy;Microstructure;Property
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发布时间：2023-12-18 - 摘要：<正>由于史杰克西的持续成功和其独特的技术,他们的新客户有着明显的增加。"因此,我们将为现有的和新的客户提供更优质的行业服务,并且于2 0 1 5年6月1日在重庆设立
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发布时间：2023-12-18
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