最新刊期
卷 ， 期 3 ， 2007
- 摘要：We have developed a micro-arc anodic oxidation device to treat the die casting magnesium alloy specimens and then to investigate the effects of anodic film on tensile properties of magnesium alloy specimens. The results indicate that anodic film possesses uniform thickness and even lightness, consisting of MgO, Mg Al2O4 and Mg2SiO4, in which the MgO content is increased with extending treated time. The effects of anodic film on the tensile properties of magnesium alloy specimens can be ignored with proper treated time, however, with the increase of treated time, the tensile properties can be slightly deteriorated as a results of defects in the anodic film.关键词：Micro-arc Anodic Oxidization;Tensile Properties;Magnesium Alloy
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发布时间：2023-12-18 - 摘要：Effects of 5% Al content（atom）on the microstructure,thermal stability and mechanical properties of Ti40Zr25Cu8Ni9Be18 amorphous alloy in substituting and doping methods have been investigated by XRD,TEM,DSC and ambient compression testing.The experimental results demonstrate that the nano-crystalline and quasicrystalline in the amorphous alloy rod with 3 mm in diameters are precipitated respectively with Al addition in substituting and doping methods.The undercooled liquid region of the amorphous alloy ribbons is increased from 41 K to 50 K in substituting methods while is decreased to 31 K in doping method.The compressive fracture stress is increased from 1 924 MPa to 2 121 MPa and the plastic strain is decreased from 3.9% to 0.2% in substituting method while is decreased to 1 475 MPa and exhibits plastic free strain in doping method with Al addition.关键词：Ti Based Amorphous Alloy;Al;Thermal Stability;Mechanical Properties
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发布时间：2023-12-18 - 摘要：(1030)%SiCp/Al-0.8Si-1.2Mg-0.4Cu composites were prepared by re-hot pressing in the conditions of rapid heating,and the variations in friction coefficient and wear rate of the composites were examined with different loads and reinforcements content.The results show that the SiCp/Al composites with high compactness can be prepared by re-hot pressing due to effectively controlling the severe harmful interface reaction in rapid heating.The frictional coefficient of the composites is increased with increasing the SiC particles content,exhibiting sharp increase under heavy loading condition.The frictional coefficient of（1030）% SiCp/Al composites is in the range of 0.3 to 0.5 in the experiment.The wear rate of the composites is increased with increasing loading from 2 N to 5 N,however,with the loading more than 5 N,the wear rate of the composites containing less than 15% SiCp contents continues to increased while is sharply decreased with more than 20% SiCp particle content,which is attributed to the creation of Al2O3 particle in the frictional interface with high SiC content under heavy loading conditions.The wear rate of 30SiC/Al composites can reach up to 1.14×10-3 mm3/m with the loading of 7 N,which shows the composites are specially suitable for the application under heavy loading conditions.关键词：SiCp/Al Composites;Re-hot Pressing;Frictional Coefficient;Wear Rate
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发布时间：2023-12-18 - 摘要：DSC and TG curves of bulk Pr55Ni25Al20 amorphous alloy and Al85Ni10Pr5 amorphous ribbons at high temperatures were mapped.The results indicate that the properties and size of the amorphous alloys have affected the accuracy of DSC and TG measured curves to a certain extent.The DSC curves and feature temperature of bulk Pr55Ni25Al20 amorphous alloy can be only accurately measured with Ar protection,while they can be accurately determined even if in the conditions of air for Al85Ni10Pr5 amorphous ribbons with high oxidation-resistant.关键词：Thermal Analysis;Amorphous Alloy;DSC
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发布时间：2023-12-18 - 摘要：The vacuum low-pressure EPC（expandable pattern casting）is a newly developed casting technique,which combines the advantages of EPC with low pressure casting process,exhibiting the features of stable filling,high accuracy and solidification under pressure.The fluidity of magnesium alloy in vacuum low-pressure EPC and the effects of pouring temperature,coating thickness and gas flux on the fluidity have been investigated,and the optimized processing parameters have been provided.The results show that the fluidity of magnesium can be greatly improved in vacuum low-pressure EPC,moreover,it is increased with increasing gas flux and decreasing coating thickness.The optimized parameters is as follows:gas flux of 35 m3/h,pouring temperature at 750780 ℃,coating thickness of 0.30.5 mm,pattern materials density of 0.16 mg/cm3,vacuum rate less than 0.03 MPa.关键词：Fluidity;Processing Optimization;Magnesium Alloy;Low Pressure Casting;EPC
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发布时间：2023-12-18 - 摘要：Numerical simulation of temperature field during Al solidification process under static high pressure has been conducted.A mathematical model of temperature field was established,in which effects of pressure on temperature field during solidification process were considered based on the relationship between pressure and metal point.The simulated results show that the higher the pressure is,the earlier the initial solidification of the pure Al is.The temperature change is increased with the increase in pressure during solidification process.关键词：Solidification;Static High Pressure;Temperature Field;Al;Numerical Simulation
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发布时间：2023-12-18 - 摘要：The phase-field method was employed to simulate the growth of dendrite in undercooled pure metal to obtain the optimized value of parameters related to models for smooth dendrite and dendritic tip growth velocity with different coupled coefficients.The results indicate that with the increase of undercooling rate and the coupled coefficient,the equaixed dendrite exhibits the morphology of developed side-branching.With high anistropic coupled coefficient,the modified dendrite can be observed.Furthermore,the side-branching dendrite can be generated in the structure if the parameters choice is unproper in the conditions of no-turbulence.关键词：Phase Field Method;Dendritic Growth;Optimization
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发布时间：2023-12-18 - 摘要：Effects of pouring temperature,stirring power and stirring time on A356 aluminum alloy semi-solid rheological slurry prepared by the complex method of traveling-wave electromagnetic stirring and low super-heat were discussed.It is found that the prepared A356 Al alloy semi-solid rheological slurry by the complex method can meet the requirements of rheological casting.Primary α-Al in the semi-slid slurry is more and more round and its grain size is finer with increasing in stirring power in the conditions of stirring time more than 6 s and pouring at temperature near to liquidus temperature.The optimized processing parameters have been obtained including stirring temperature of 630 ℃ and stirring power of 1.2 kW and stirring time of 6 s.关键词：A356 Al Alloy;Semi-solid Slurry;Traveling-wave Electromagnetic Stirring;Low Super-heat;Rheological Casting;Microstructure
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发布时间：2023-12-18 - 摘要：The A356 aluminum alloy semi-solid slurry by damper cooling tube method was prepared under different pouring temperature conditions,and was compared with ones by cooling slope method.The results show that with decreasing in pouring temperature,the grain size and shape factors become smaller and smaller,which means the spherodization of grain is higher and higher.Compared with ones by cooling slope method,the grain in the semi-solid slurry exhibits finer and more roundness by damper cooling tube in the conditions of the same processing parameters.关键词：Damper Cooling Tube Method;Cooling Slope Process;Semi-solid Slurry;Pouring Temperature;Grain Size;Shape Factor
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发布时间：2023-12-18 - 摘要：Effects of holding time and holding temperature on stability of electromagnetic stirred ZL117 alloy slurry have been investigated.The experimental results show that the diameter of primary Si particle in the semi-solid slurry is gradually increased with the increase of holding time,in which the growth velocity of the primary Si particle is very slow before 15 min while is rapidly increased after 15 min.The diameter of primary Si particle is increased gradually with increasing holding temperature.The shape coefficient of primary Si particle is increased gradually with extending holding time,whereas,it is slowly increased before 15 min and rapidly increased after 15 min.The minimum shape coefficient of primary Si particle can be obtained at 620 ℃,and the shape coefficient is increased with increasing in holding temperature at 620 ℃650 ℃.关键词：Hypereutectic Al-Si Alloy;Stability;Semi-solid Rheoforming;Primary Si;Holding Time;Holding Temperature
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发布时间：2023-12-18 - 摘要：Thin-walled aluminum alloy shell was prepared by squeezing casting in a special mould.The effects of preheated temperature of mould,pouring temperature,pressure and holding pressure time on deformation of the components were expounded,meanwhile,the tensile properties,microstructure and fracture morphology of the components were observed.The results show that increasing temperature is favorable for the filling of the liquid aluminum alloy,and the optimized pouring temperature is 720740 ℃.The plasticity and strength of the components poured at 720 ℃740 ℃ can meet the requirements,and the microstructure of the components exhibits fine grain size and dendrite-absence as well as tough fracture features.关键词：Aluminum Alloy;Thin-walled Component;Squeezing Casting
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发布时间：2023-12-18 - 摘要：In the design of die casting die with screw thread,the automatic screw thread unloading is a difficult point.A toothed rack is commonly adopted for the automatic screw rotational unloading.However,a new mechanism,mechanism of screw arbor with large helical angle,is adopted for automatically rotational screw thread unloading in the designed die casting die.The mechanism uses the open-die of die casting machine to provide the power for rotation of the core with screw thread,in which the mechanism of screw arbor with large helical angle changes the rectilinear movement of the open-die of die-casting machine to rotation of the core with screw thread,realizing the automatic screw thread unloading,which can improve the reliability of the production and save the die cost.关键词：Die Casting Die;Screw Arbor with Large Helical Angle;Core with Screw Thread;Rotational Screw Thread Unloading
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发布时间：2023-12-18 - 摘要：J1125 type horizontal cold chamber die casting machine was used to produce the aluminum alloy housing of motorcycle based on its complicated shape,thin-wall and small profile dimension.One mould-four cavity structure was used in the design of the die casting die,in which a main runner with proper and uniform section and four associated runner were considered to ensure filling well,optimizing the die casting die structure.关键词：Housing;Die Structure;Die Casting Machine;Gating System
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发布时间：2023-12-18 - 摘要：The low-cycle fatigue behavior of the die cast Mg-7Al-0.5Y magnesium alloy has been investigated in case of full reversed total strain control mode.The experimental results reveal that die cast Mg-7Al-0.5Y magnesium alloy exhibits the cyclic strain hardening with various total strain amplitudes,in which the dynamic strain aging phenomena can be observed during low-cycle fatigue deformation with the total strain amplitudes of 0.9%.For the die cast Mg-7Al-0.5Y magnesium alloy,the relations between the elastic strain amplitude,plastic strain amplitude and reversals to failure can be described by the Basquin and the Coffin-Manson equation,respectively.The SEM analysis of the fracture morphology shows that the fatigue crack is created at the surface of the specimens and propagated in a transgranular mode in case of low-cycle loading.关键词：Die Cast Magnesium Alloy;Low-Cycle Fatigue;Dynamic Strain Aging;Fatigue Fracture
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发布时间：2023-12-18 - 摘要：A three-dimensional mathematical model coupled turbulent flow with transfer heating has been established to simulate the flow field and solidification of liquid steel in molten pool in continuous casting using a wedge type melt delivery system.The results show that the uniform flow and solidification of liquid steel in the continuous casting can be realized by using the wedge delivery system,improving the quality of the continuous casting strip.关键词：Twin-roll Strip Continuous Casting;Flow Field;Temperature Field;Numerical Simulation
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发布时间：2023-12-18 - 摘要：2024 aluminum alloy ingot with 135 mm in diameters was produced by air-slip semi-continuous casting with varied processing parameters.The effects of pouring temperature,pouring velocity,gas pressure on thickness of solidified shell and microstructure of aluminum alloy ingot have been described.The results show that the ingot with uniform fine microstructure and thin-walled solidified shell as well as smooth surface can be produced successfully with filling at 710 ℃,at 175 mm/min,gas pressure of 0.6 MPa and cooling pressure of 580 kPa.关键词：Air-slip Casting;2024 Aluminum Alloy;Microstructure;Pouring Temperature;Filling Velocity;Gas Pressure
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发布时间：2023-12-18 - 摘要：The gap between investment enterprises at home and abroad was described,and improving quality of investment castings by strengthening process control was reviewed.Trial-production and process control before production-volume should be strengthened to improve the geometric accuracy,including improving design of product,strictly measuring the sizes of mould,wax pattern and castings,and strictly controlling the quality of wax,temperature of injection,temperature and humidity of wax pattern chamber.Besides controlling the viscosity of coating,SiO2 content and pH values,the humidity and uniform temperature of surface layer of mold shell should be considered in eliminating surface defects in the castings.关键词：Investment Casting;Geometric Accuracy;Surface Quality;Process Control
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发布时间：2023-12-18 - 摘要：The experience of production of grinder body with 42 tons in weight in full mold（FM）was described,in which no-bake furan resin sand was used to mold and outer-chill was set on the slide-way and exhausted pipe was rationally distributed.The measurements show that grinder body in geometric size,mechanical properties,chemical composition and in hardness of slide-way can meet the requirements of technological parameters,providing a reference for production of large and heavily-large cast-iron machine body in full mold casting.关键词：Full Mold （FM）;Large Grinder Body;Technological Design
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发布时间：2023-12-18 - 摘要：It was believed that the carbon defects in the castings can be effectively eliminated if the major polystyrene foam pattern is exhausted in ways of liquid type by analyzing the formation mechanism of carbon defects during the decomposition of polystyrene.The wettability of coating for liquid decomposition product of the polystyrene has been given,which was validated by the experimental results.关键词：Lost Foam Casting;Coating;Wettability;Carbon Defects
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发布时间：2023-12-18 - 摘要：The effects of P and Re complex modification with different P and Re addition on the microstructure and mechanical properties of hypereutectic Al-20Si alloy have been investigated.The results show that P and Re complex modification can greatly refine the primary Si phase and eutectic Si phase,in which the size of primary Si phase is decreased and spheroidized,and the eutectic Si phase is converted from needle-like into particles.The optimized microstructure and mechanical properties can be observed with 0.08%P and 0.6%Re addition,in which the tensile strength at room and high temperatures is 306 MPa and 187 MPa,respectively,improved by 20% and 34% than that of un-modified alloys,and the elongations at room and high temperatures reach up to 0.48% and 1.58% respectively,improved by 40% and 88%respectively than those of un-modified ones.关键词：Hypereutectic Al-Si Alloy;Complex Modification;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The refining process with porous plugs in holding furnace was approached,especially the advantage of porous plugs refining process,the layout of porous plugs in holding furnace and the analysis of hydrogen degassing efficiency.The hydrogen degassing efficiency can be reach up to 30%40% with 18 porous plugs in 85t rectangular holding furnace.Hydrogen degassing efficiency could be improved by optimizing the layout of porous plugs in holding furnace and improving the compatibility between porous plugs and surrounded refractory materials.关键词：Porous Plugs;Hydrogen Degassing Efficiency;Refinement
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发布时间：2023-12-18 - 摘要：Effects of isothermal heat treatment on microstructure and properties of cast Al-7Si-4Cu alloy have been investigated.It is revealed that isothermal heat treatment,including adjusting time and temperature,can not only refine the microstructure of the alloy,but also improve the mechanical properties of the cast Al-7Si-4Cu alloy.The Si phase in microstructure of the alloy can be spheroidized and refined with extending isothermal time and increasing isothermal temperature in the condition of a given cooling rate.The disperoids in the microstructure can be observed at semi-solid temperature with holding time for 5 min,which becomes more and more with increasing in holding temperature,however,the disperoids would be disappeared with holding time for 10 min.The micro-hardness of the alloy can be improved with increasing in spheroidization and fine and uniform distribution of Si phase.关键词：Isothermal Treatment;Al-Si-Cu Alloy;Hardness;Microstructure
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发布时间：2023-12-18 - 摘要：The toughness of in-situ synthesized VC/Fe composites with a lot of uniformly distributed fine disperoids can be deteriorated due to the existence of some net-like Fe3C particle at grain boundary.The effects of heat treatment on microstructure and properties of in-situ synthesized VC/Fe composites have been approached.The results show that heat treatment can change the morphology and amounts of Fe3C phase at grain boundary,however,it dose not affect the size and distribution of VC particle.With increasing the austenizing time,the amounts of Fe3C phase can be decreased with the morphology trending towards discontinuous net-like structure.The composites is mainly composed of dispersively distributed VC particles and martensite with austenizing for 3 hours at 960 ℃ and quenching,where the hardness of the composites is 62 and impact toughness is 7.9 J/cm2.关键词：Reaction Casting;VC/Fe Composites;Heat Treatment;Microstructure;Properties
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发布时间：2023-12-18 - 摘要：The abrasive attrition and wear properties of in-situ carbide reinforced steel matrix composites（Fe（Ti,W,Cr,V,Nb）Cp）were measured.The results show that in-situ carbide particle exhibits fine and round morphology and uniform distribution in the in-situ steel matrix composites,reaching up to 42.8%（volume fraction）,which results in the composites possessing excellent wear resistance.In the condition of abrasive attrition,the wear loss is mainly caused by micro-cutting,particle shattered and brittle micro-peeling.The wear resistance of in-situ steel matrix composites can be greatly improved with increasing Re and alloying elements addition.关键词：In-situ Steel Matrix Composites;Complex Carbide Reinforced Particle;Wear Resistance
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发布时间：2023-12-18 - 摘要：Effects of working conditions on bonding strength and conductive properties of steel-aluminum cladding interface have been investigated.The results show that after 10 times heating-cooling cycle from 400 ℃ to the room temperature,the cladding interface keeps strong bonding and the interfacial electric resistance remains 0.50.6 μΩ,which vary little compared to as-claded ones.With the cycle from 500 ℃ to room temperature,the interfacial bonding keeps well after 4 cycles.However,slight crack can be observed in the interface after 5 cycles due to increasing the diffusion depth of the Fe element into the Al matrix,furthermore,the crack in the cladding interface becomes more and more serious after 810 cycles.In addition,the interfacial electric resistance is increased with increasing heating times at 500 ℃,especially exhibiting sharply variation after crack in the cladding interface.The desirable working temperature of the steel-aluminum rods is about 400 ℃.关键词：Steel-aluminum Electric Conducting Rod;Interface;Microstructure;Conductive Properties
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发布时间：2023-12-18 - 摘要：The effects of Sr content on the microstructure of in-situ Mg2Si/Al composites have been observed by XRD,SEM and extracted technology.And spherical semi-solid microstructure in the composites can be successfully achieved by isothermal heat treatment.The results show that with the increase of Sr content,primary Mg2Si particles are converted from dendritic phase into polygonal and then to quadrangle with grain size of about 40 μm.After isothermal heat treatment,both the primary Mg2Si particles and α-Al phase in the composites are spheroidized.The spheroidization mechanism has been approached briefly.关键词：In-situ Mg2Si/Al Composites;Modification;Semi-solid;Microstructure Evolution
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发布时间：2023-12-18 - 摘要：CuAlBe wires with columnar grain structure were prepared by the heated mold continuous casting to compare with single crystal wires.Experimental results show that columnar grain wires exhibit excellent superelasticity and strain recovery property similar to single crystal wires,and its bending fatigue life lies between polished and unpolished states of single crystal.The absence of transformation was observed when heating to 500 ℃,whereas heating to 700 ℃,α phase is precipitated,which can slightly decrease the strain recovery after soldering,so the wires are able to undergo no less than 30% plastic deformation.关键词：CuAlBe;Heated Mold Continuous Casting;Bending Fatigue;Plastic Deformation
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发布时间：2023-12-18 - 摘要：The influence of annealing temperature（400600 ℃）on two-way shape memory effects in NiTiCu shape memory alloy（SMA）with the thermomechanical training and the thermal cycling has been investigated.The results show that the maximum two-way shape memory strain of 4.2% occurs in the aging temperature of 500 ℃ after 100 thermomechanical trainings.During 2000 thermal cycling,the two-way shape memory strain is faded rapidly with increasing in thermal cycling in initial 100 thermal cycling while it is faded slightly towards a stable value with more than 100 thermal cycling.The Ms,Mf,As,Af values are raised with the increases of aging temperature before thermal cycling,however As,Af values are decreased slightly with the aging temperature more than 550 ℃,while after thermal cycling,the Ms,Mf critical values and As,Af critical values can be observed at aging temperature of 550 ℃ and 500 ℃ respectively.The transformation temperature would be shifted after thermal cycling with the same annealing temperature.关键词：Aging Temperature;Shape Memory Alloy;Two-way Shape Memory Effects
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发布时间：2023-12-18 - 摘要：地藏王工艺品总体高2m,其中佛像高1.5m,莲花底座高0.5m,采用熔模精密铸造和砂型铸造相结合的分体、镶嵌式复合铸造工艺,为保证佛像头部的精致,头部、帽冠、两只手、莲花座采用精密铸造,再用精铸佛像头和佛身用镶嵌式复合铸造工艺,采用粘土表干型用砂,在制好的型腔内侧均匀喷涂一层特制快干涂料,浇注出佛像,再拼焊帽冠、两只手、莲花座,经处理后完成地藏王像。关键词：分体制作;精密铸造;砂型铸造;加工装配;表面处理
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发布时间：2023-12-18 -
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