最新刊期
卷 33 ， 期 11 ， 2013
- 摘要：Fine-grained structural materials（FSM for short）with the same composition of Al-18Si alloy were used as the master alloy to modify the microstructure of HCC Al-18Si alloys because of its structural heredity.The influences of FSM master alloy on the microstructure and uniformity of Al-18Si alloy were investigated by SEM（scanning electron microscopy）and DSC.The results show that FSM master alloy can reduce the size of primary Si and improve the uniformity of the billet along the cross-section.The addition of FSM master alloy can increase the nucleation temperature of primary Si and reduce the latent heat of crystallization.In addition,with the addition of the master alloy,the alloys is less sensitive to cooling rate by DSC analysis,which reveals that the differences of nucleation temperature at surface and center of the billet is decreased.关键词：Hypereutectic Al-Si Alloys;Refinement Modification;Microstructure;Structural Heredity
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发布时间：2023-12-18 -
Effect of Solidification Pressure on Si Distribution in Vacuum Counter-Pressure Casting ZL114A Alloy
摘要：Effects of solidification pressure on Si distribution in vacuum counter-pressure casting ZL114A alloy were investigated through analyzing Si distribution across the ZL114Avacuum counter-pressure casting samples subjected to different solidification pressure.The results indicate that with the solidification pressure during vacuum counter-pressure casting,heterogeneous Si distribution can be observed in ZL114Acasting samples,where the Si concentration in the center is lower than that in the surface.With the increase of solidification pressure,the segregation of Si in the ZL114Acasting samples is increased continuously,and the segregation reaches the maximum value with 400kPa pressure.关键词：Solidification Pressure;Vacuum Counter-Pressure Casting;ZL114A;Si Segregation- 2
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发布时间：2023-12-18 - 摘要：The copper-matrix composites reinforced with different nano-particles of Al2O3,SiO2,SiC and MgO in varied volumetric fraction were fabricated by internal oxidation and by powder metallurgy.The effects of preparation technology、volumetric fraction of reinforcements and thermal expansion coefficient difference between copper-matrix and reinforced particles on the electrical conductivity of the copper-matrix composites prepared were investigated.The results show that the electrical conductivity and density of Al2O3/Cu composite fabricated by internal oxidation which are increased with decreasing in Al2O3volume fraction are higher than those by powder metallurgy.The electrical conductivity of Al2O3/Cu composites is reduced with the increase of thermal expansion coefficient difference between copper-matrix and reinforced particles,which is relative with the values of calculation of the thermal stress at the copper matrix/reinforcement interface.Microstructure observation shows that the fine Al2O3particles are distributed more uniformly with alignment in the Al2O3/Cu composites fabricated by internal oxidation compared with that by powder metallurgy.关键词：Copper-Matrix Composites;Electrical Conductivity;Powder Metallurgy;Interface Thermal Stress
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发布时间：2023-12-18 - 摘要：Effects of different aging temperatures and time on the microstructure and mechanical properties of Al-5Fe based alloy were investigated.The results show that the aging treatment has a significant effect on microstructure and properties of the Al-5Fe alloy.The precipitation of strengthening phase is inadequate with a short aging time,which results in a lower performance,while with increasing aging time,the strengthening phase is precipitated gradually.However,with the aging time more than 6h,strengthening phase particles are coasened,leading to the decrease of mechanical properties of the alloy.Under the experimental conditions,the tensile strength,yield strength and elongation reach 312MPa,300MPa and 3.8%,respectively,with aging temperature of 180℃for 6h.关键词：Al-5Fe Alloy;Rolling;Aging Treatment;Strength;Elongation
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发布时间：2023-12-18 - 摘要：Texture and tensile property heterogeneities between the center and the outer layer of extruded AZ80bar with 230mm×140mm cross-section were investigated.The macro-textures of the center and three locations of the outer layer were measured by X-ray diffraction（XRD）technique.Pole figures of these four positions show that although texture at different positions exhibits fibrous texture,distributions of（0001）and{1120}pole are different from each other.The yielding behaviors of ED,TDand NDsamples in the center and in the outer layer were investigated by stress-strain curves.The results reveal that:（1）in both the center and the outer layer,yield strength of EDdirection is much higher than that of TDor NDdirection,however,the difference between the yield strength of TDand NDcan be ignored;（2）the yield strength of the center in ED,TDand NDis slightly higher than yield strength of the outer in the corresponding direction.Tensile property heterogeneity can be well analyzed by the texture feature.关键词：Magnesium Alloy;AZ80;Extrusion;Texture;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Combining the spinning rotor degassing equipment self-developed for aluminum alloy melt,the influences of structure,size and location of the bluff body on the diameter,quantity and distribution of bubble were investigated by using the consecutive photographic technology of the digital camera.According to the experimental results,the desirable structure of bluff body is the cuboid,and the optimized ratio between the inner diameter of the crucible,the width and location of the bluff body is 6∶1∶0.7.The spinning rotor degassing equipment self-developed with the bluff body based on the optimized ratio was used to purify and degassing ZL101alloys.It is shown that the effect of purifying and degassing is excited.关键词：Spinning Rotor Degassing;Bluff Body;Optimization Ratio;Purifying and Degassing
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发布时间：2023-12-18 - 摘要：Gating system of ZL114Alower case of reducer was designed,and the three-dimensional modeling of the casting and gating system was established.The filling and solidification processes of the casting were simulated.Based on the different criterions,the simulation results of the castings were analyzed.The quality of the filling and solidification processes was evaluated,and the positions of defects were visualized.Then the gating system was optimized.关键词：Gating System;Filling and Solidification;Numerical Simulation
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发布时间：2023-12-18 - 摘要：In order to observe the flow condition of the vibration casting process,the two-phase flow model and the dynamic mesh were coupled to simulate the fluid flow in the vibration casting process.In Fluent software,sine harmonic vibration function was writed into the calculation by the UDF function,combined with the VOF model,and the physical field data of two-phase flow were presented under vibration casting process.A simple experimental device was designed for conducting hydraulic filling experiment,and the experimental results are consistent with the simulated ones,confirming the feasibility of the numerical simulation.The comparison results between the vibration casting and traditional casting process were described,which indicated that the vibration conditions were beneficial to filling.关键词：Vibration Casting;Numerical Simulation;Dynamic Mesh;Two-Phase Flow
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发布时间：2023-12-18 - 摘要：The samples with 100 mm×150 mm of commercial aluminum alloys including ZL101A,ZL201A,2A50,2A14,2A12and 7A04were prepared by squeezing casting to analyze microstructures and mechanical properties.The results show that all these alloys prepared by squeeze castings exhibit fine grain structure,and the tensile-ruptured samples are characterized by the plastic fracture mode.The mechanical properties of ZL101A,ZL201A,2A50,2A14,2A12and 7A04aluminum alloys are presented as follows at 200MPa:the tensile strength of 295,385,340,425,425,475MPa,respectively;the yield strength of 220,225,310,390,320,410 MPa,respectively;the elongation of 8.0%,15.5%,4.5%,3.5%,9.5%,7.5%,respectively;the impact toughness of 4.0,12.0,4.0,3.0,3.0,3.5J·cm-2,respectively;and the hardness（HB）of 95,106,117,142,126,145,respectively.关键词：Casting Al Alloy;Wrought Alloys;Squeeze Casting;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：According to the structure characteristics of uneven wall thickness、product requirements and annual output of cylinder head of heavy truck engine,die casting process instead of low-pressure casting process was adopted.The die casting process from the aspects of material composition、gate and injection pressure was improved and optimized,and the die casting process parameters were determined,finally the product defects including solder、crack and porosity were eliminated.Product qualified rate is approximately 95%steadily through testing plane hole leakage at random.关键词：Cylinder Head;Uneven Wall Thickness;Die Casting Process;Injection Pressure
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发布时间：2023-12-18 - 摘要：Aimed at the complex side cover of gear-box,the gating system design was optimized by model flow analyzing software.Through shot blasting,increasing the Cu content in the alloy,modifying corepin design and cooling system as well as back-off method,surface strength and hardness of the mould are improved,and bending deformation and shrinkage porosity are avoided,increasing qualified rate of the product from 70%to more than 95%.关键词：Model Flow Analyzing;Cu Content;Core Pin
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发布时间：2023-12-18 - 摘要：Aiming at blowhole defects easily occurred in transmission case with large size and complex structure,filling process of transmission case was visualized.Meanwhile,practical transmission case housing produced to be analyzed comparatively.Through observing the location easily to form defects and analyzing the mechanism,the availability of the design was verified,which provided a reference for adjusting processing parameters and determining process scheme.关键词：Transmission Case Housing;Blowhole Defects;Process Scheme
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发布时间：2023-12-18 - 摘要：The history of fire-resistant hydraulic fluids was introduced,and the comparison between water-glycols and fatty acid ester（HFD-U）based hydraulic fluids was conducted.Finally,the benefits for Japanese die casting industry by using polyol ester based hydraulic fluids were described.关键词：Fire-Resistant Hydraulic Fluids;Water-Glycol;Fatty Acid Ester;Japanese Die Casting Industry
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发布时间：2023-12-18 - 摘要：Bimetallic curvature pipes were produced by liquid-solid casting technology combining with lost foam casting.Effects of different vacuum rate on the bonding interface of bimetallic curvature pipes were observed.Meanwhile,microstructure,hardness and impact toughness of bimetallic pipes with desirable bonding were investigated.The results indicate that bimetallic pipes present good bonding interfaces with the absence of vacuum pressure.The hardness of the high chromium cast iron is increased slightly,and the impact toughness is improved apparently,reaching 26J·cm-2.关键词：LFC;Liquid-Solid Casting;Bimetallic Pipes
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发布时间：2023-12-18 - 摘要：<正>我公司生产的复杂内腔阀体,其结构见图1。从图1看,铸件壁厚较为均匀,热节区域主要存在于左右两个法兰上。但是该阀体内腔较为复杂,常用的工艺方法解决出芯问题困难,且由于通过该阀体的液体是非中性液体,要求其材质为2Cr13,铸件不得有裂纹、
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发布时间：2023-12-18 - 摘要：A simple and easily used ultrasonic cleaning system was designed,and seven kinds of pre-treatment on SiC particles were performed.It is found that an optimized pretreatment process is as follows:ultrasonic cleaning,baking oxidation at high temperature and pre-heating.Micro-fine powder on the SiC particles can be cleaned off at 1000℃after ultrasonic cleaning process,and high temperature baking can promote the reactive wettability.Holding temperature can avoid the occurrence of second absorption.As a result of surface absorption,wettability of particle with the melt can not be improved only by high temperature baking.Absence of small and fine particles can be observed in absorption of the SiC particle after ultrasonic clean for 60min.关键词：SiCP/7050 Aluminum Metal Matrix Composite;SiCP Pretreatment Technology;Ultrasonic Cleaning;Surface Adsorption
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发布时间：2023-12-18 - 摘要：TiC dispersion strengthened tungsten matrix composites were prepared by the mechanical milling,and the optimization of the milling parameters,such as milling time,milling velocity,ball-powder ratio,the liquid to the ball ratio,was carried out based on observing the W/TiC grain size,microstructure of the powders,and testing mechanical properties of the sintered samples.The results show that the optimized milling parameters are presented as follows:the 4050hof the milling time,the 400500r/min of the milling speed,the 1.52.5∶1of the liquid to the ball and the powders ratio,and the 1015∶1of the ball to the powders ratio.And the powders present a sphere-like shape with the uniform grain size and the smooth surface.For the sintered composites after the milling,both of the relative density and the flexural strength are improved greatly.关键词：Tungsten;TiC;Mechanical Milling
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发布时间：2023-12-18 - 摘要：The patent data of titanium alloys in Derwent Innovations Index（DII）were collected,and the quantitative result reveals that the aerospace involves the highest number of application on titanium alloys.Based on the above result,it was got deeper insight in applications in the aerospace,such as patent numbers of past years,the competitive ability of facilities,patent quoted times and patent technology layout in quantitative ways.Furthermore,statistical analysis was made to examine whether the two&eight principle worked in the patent analysis.Finally,the constructive suggestions for the enterprises in titanium field were presented.
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发布时间：2023-12-18 - 摘要：Normal rolling technology can cause difference of performance between the center and the surface of the rolling samples as a result of adequate deformation in the center,while asymmetric rolling can assure the homogeneity of the structures and properties of rolling plates in the central and surface due to realizing the severe deformation with a lower reduction.RRA（Retrogression and Re-Aging）heat treatment could improve SCC properties of the high strength alloys without decreasing their strength.Two technologies above mentioned could meet the requirements of aerospace industry.The new hot rolling and heat treatment technology,especially the asymmetric Rolling and RRA for the middle-thick plate production,were reviewed.关键词：Aluminum Alloy;Asymmetric Rolling;RRA;Heat Treatment
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发布时间：2023-12-18 - 摘要：Effects of mechanical vibration on solidification structure and hardness of H62brass were investigated by changing amplitude.The results show that solidification structure of H62brass can be improved significantly by mechanical vibration,which is converted from coarse columnar crystal to equiaxed crystal.Meanwhile,mechanical vibration has obvious effects on shrinkage porosity in central part and on homogenization of microstructure.With the increase of amplitude,the grain size is decreased and hardness of the alloy is increased.关键词：Mechanical Vibration;H62Brass;Solidified Structure;Hardness
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发布时间：2023-12-18 - 摘要：Based on the Faraday’s Law of electromagnetic induction,the axial magnetic fields at different radiuses and positions along the axis of the cold crucible made of copper were measured with a magnetic probe.Several factors influencing the magnetic fields were investigated such as the exciting current,the frequency and distance between the magnetic-exciting coils and the bottom of the crucible.The experimental results show that:the strong axial magnetic fields are induced within the coils,and the magnetic fields are decreased with the increase of the distance between the coils and measuring positions,which exhibits distribution asymmetrically to the central vertical plane.With the increase of the radius,the axial magnetic fields are increased slightly,and it is distributed symmetrically to the center axis.In addition,the copper crucible can make the fields distribute uniformly.The increase of the exciting current,the decrease of the frequency and the distance between the coils and the bottom of the crucible will also make a contribution to the enhancement of the axial magnetic fields.关键词：Non-Contact Melting;Water-Cooled Copper Crucible;Induction Heating
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发布时间：2023-12-18 - 摘要：The master alloy Mn-25Al containingτ-AlMn phase was prepared by vacuum quenching furnace.Meanwhile,effects of manganese on grain refinement in Mg-6Al alloys were analyzed by using XRD（X-ray diffraction）,SEM（scanning electron microscope）and EDS（energy dispersive spectrometer）,and so on.The results reveal that the refining effects of Mn-25Al master alloy and MnCl2are obviously superior to mixture containing MgCO3,C2Cl6and MnCl2.The best refining effects can be observed in magnesium alloy with addition of 0.3% Mn,however,the grain size is coarsened with further increasing in manganese content.τ-AlMn phase can be acted as desirable heterogeneous nuclei by analyzing the disregistry.Unfortunately,the Al-C compound which derived from carbon-containing modificator easily absorbed on the surface of Al-Mn phase and formed low-potency Al-C-Mn compound,resulting in the coarseness ofα-Mg grain.关键词：Magnesium Alloy;Heterogeneous Nucleation;Grain Refinement;Mn
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发布时间：2023-12-18 - 摘要：Filling process of thin-walled casting in the traveling magnetic field was analyzed with the help of low melting point metal gallium physical simulation.The results reveal that filling ability,filling flow and filling length are increased,while the filling time is decreased with the increase of the magnetic induction intensity.The stainless steel bottom-mold was superior to ceramic bottom-mold,and the optimized process parameters were presented.关键词：Travelling Magnetic Field;Thin-Walled Casting;Magnetic Induction Intensity;Filling Process
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发布时间：2023-12-18 - 摘要：Microstructures of the alloy without treatment,treated by mechanical vibration,ultrasonic and by compound action of ultrasonic and mechanical vibration were investigated comparatively.Influences of pouring temperature and preheating temperature of mold on solidification structure of the alloy after compound treatment of ultrasonic and mechanical vibration were expounded.The results show that primary grain in magnesium alloy AZ91D-3Ca can be refined significantly by compound treatment of ultrasonic and mechanical vibration,which is apparently superior to mechanical vibration treatment or melttreatment by ultrasonic.The second phases with short strips or granular are distributed uniformly at grain boundary,and tensile strength and elongation of the alloy with compound treatment are increased by 79.67%and by 35.71%,respectively.When pouringt temperature is in range of 610700℃,obvious refining effect can be observed at different pouring temperature,however change of microstructure refinement is independent on change of pouring temperature.With the increase of preheating temperature of the mold from 20℃to 600℃,primary phase is converted from incomplete dendrite to equiaxed or rossette-shaped crystal with slight coarseness.关键词：Ultrasonic;Mechanical Vibration;Compound Treatment;Solidification Structure
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发布时间：2023-12-18 - 摘要：Effects of Cd and Nd addition on microstructures,mechanical properties and electrochemical behavior of ZK60alloys were investigated by ICP tester,OM（optical microscope）,SEM（scanning electron microscope）and universal tensile testing as well as electro-chemical working station.The results show that ductility and tensile strength of the alloy with Cd addition can be improved greatly,however,the continuous net-like intergranular phases in Mg-Zn-Nd-Zr alloy obviously deteriorate the mechanical properties（strength and elongation）.In addition,corrosion potential is significantly improved in the Mg-Zn-Zr alloy with Nd addition.The alloy with proper Cd and Nd compound additions can not only improve mechanical properties,but also enhance corrosion resistance.关键词：Magnesium Alloy;Mechanical Properties;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of LVPMF on microstructure and mechanical properties of Al-12.4Si alloy were investigated by introducing a low voltage pulsed magnetic field（LVPMF）during solidification.The results show that the primaryα-Al and eutectic silicon in the Al-12.4Si alloy are refined by LVPMF treatment.With the increase the voltage of LVPMF,eutectic Si phase is transformed from acicular structure into fine fibrous or granular ones.Meanwhile,the tensile strength and elongation of Al-12.4Si alloy under LVPMF at room temperature reach up to 187 MPa and 5.2%,respectively,which are increased by41.7%and by 173.7%,respectively,compared with those of the eutectic Al-Si alloy without LVPMF treatment.关键词：Low Voltage Pulsed Magnetic Field;Eutectic Al-Si Alloy;Solidification Microstructure;Refinement;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Microstructure and hardness of cast AM50magnesium alloy were analyzed,and effects of T4and T6treatment on microstructure and hardness of the alloy were approached.The results reveal that the microstructure of the AM50alloy is composed ofα-Mg phase andβ-Mg17Al12phase which is discontinuously distributed along the primary phase boundary.After solid solution treatment,β-Mg17Al12phase is dissolved gradually into theα-Mg phase,resulting in the uniform and fine distribution in the microstructure,however,the hardness is decreased slightly.关键词：AM50Magnesium Alloy;Microstructure;Hardness;Heat Treatment
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发布时间：2023-12-18 - 摘要：The three-dimensional vibration technology used for making semi-solid alloy slurry was presented.Influences of vibration frequency in Z,XYand XYZdirection on the structures of water quenched Al-9Si-Mg alloy specimen were investigated by quantitative analytic technique through the disturbing pillars installed in a self-designed sloping board.The results indicate that at the Z,XYand XYZvibration direction,with the increase of the vibration frequency,the grain size is decreased gradually with the spheroidization of the grain shape.When the vibration frequency is 30Hz,there exists a small amount of dendrite in microstructure regardless of Z,XYand XYZvibration direction,and with the increase of vibration frequency,the dendrite disappears gradually.With the vibration directions of XYZand the frequency of 50Hz,a fine grain structure can be observed,in which the grain size reaches 6.58μm with0.59of shape factor.关键词：Three-Dimensional Vibration;Vibration Frequency;Semi-solid;Al-9Si-Mg Alloy
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发布时间：2023-12-18 - 摘要：Semi-solid slurries of 2024wrought aluminum alloy were produced by self-inoculation technique.The microstructure and typical defects of wheel hub parts which were trial-produced by rheosqueeze forming were investigated,and the countermeasures of these defects were presented.The results reveal that through increasing the velocity of the punch and filling pressure as well as raising preheating temperature of the mould,misrun and cold shut in the wheel hub can be eliminated.Through increasing hold-pressure and hold time,shrinkage porosity（hole）can be decreased.Through controlling solid fraction of the slurries,adjusting filling pressure and holding time,hot crack is avoided.关键词：Self-inoculation Method;2024 Wrought Aluminum Alloy;Semi-solid Rheo-Squeeze Forming;Typical Defects
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发布时间：2023-12-18
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