最新刊期
卷 ， 期 4 ， 2007
- 摘要：The microstructures of 2618 aluminum alloy after and before TMA have been observed by TEM, and the refining effects of the TMA on aging precipitates S′in 2618 aluminum alloy have been revealed. The reason for obviously decreasing the PFZ around the grain boundary in TMA 2618 aluminum alloy has been approached, and the thermo-kinetic behavior of the TMA was described.关键词：Heat Resistant Aluminum Alloy;TMA;Microstructure;Thermo-kinetic Behavior
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发布时间：2023-12-18 - 摘要：The variations in the electric resistance and structure of amorphous Cu50Zr42Al8 alloy annealed at different temperatures （500600 ℃） for 20 minutes and at 550 ℃ for different time （1060 min） have been measured by the Huygens electric bridge measurements and X-ray diffraction. It is found that the electric resistance of the bulk amorphous Cu50Zr42Al8 alloy is fast increased in the ranges of 515520 ℃ near the crystallization temperature, exhibiting the maximum electric resistance phenomenon, furthermore, it is shown the trend of increasing initially and then decreasing with the increase of annealing temperature and holding time. The mechanism of above results is approached based on the structure changes resulting from order-atom clusters and phonon-electron scattering.关键词：Cu-based Bulk Amorphous Alloy;Crystallization;Electric Resistance;Order-atom Cluster;Microstructure
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发布时间：2023-12-18 - 摘要：By using the CRP, the influences of forced convection, melt temperature and reactor temperature during solidification on the microstructure of the A357 semi-solid slurry have been investigated. The results show that melt forced mixing can result in the creation of fine spheroidal primary phase in the A357 semi-solid slurry, which is sharply different from that being un-treated by melt mixing. It is helpful for reducing the size and promoting the formation of near-spheroidal shape of primary phase with low melt temperature and reactor temperature, such as the melt temperature less than 640 ℃ and reactor temperature less than 300 ℃. Further analysis reveals that melt mixing can change the solidification structure of the slurry by controlling the nucleation and growth of the primary phase in the melt.关键词：CRP;Semi-solid Slurry;Nucleation and Growth
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发布时间：2023-12-18 - 摘要：The low cycle fatigue behavior of ZL101-T6 aluminum alloy has been investigated , focusing on the crack initiation and propagation in the alloy, by scanning electronic microscope （SEM） and metallographic microscope. The results show that the crack of eutectic Si phase is mainly responsible for the low cycle fatigue crack initiation. The amount of crack Si particles is increased with increasing in fatigue cycles, and the crack rate of Si particle,which can be accelerated with the increase of strain amplitude,promotes the propagation rate of fatigue crack. The propagation of fatigue crack is mainly dependent on the connection of adjacent cracking eutectic Si particles during initial cycling stages. With the growth of micro-crack, transgranular coalescence can be taken place in Al matrix to form a long fatigue crack, resulting in the final rupture of the alloy. So the final rupture in the ZL101 aluminum alloy is characterized by the transgranular fracture.关键词：ZL101 Aluminum Alloy;Low Cycle Fatigue;Crack Initiation;Crack Propagation;Eutectic Si
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发布时间：2023-12-18 - 摘要：A finite element model coupled electromagnetic field with temperature field has been established based on induction heating theory to simulate the induction heating process of continuous casting slab by universal ANSYS software, and to obtain temperature field of the slab related to time variation. The characteristics of temperature-increment and influential factors of the continuous casting slab during induction heating process are analyzed. The results show that the temperature homogenization can be effectively improved by adjusting the frequency of heating device and exciting current.关键词：Continuous Casting-Direct Rolling;Electromagnetic Induction Heating;ANSYS;Eddy Current
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发布时间：2023-12-18 - 摘要：Grain refinement can obviously improve the mechanical properties of magnesium, which is a approach to strengthen magnesium alloy. The effects of squeezing casting combining with squeezing deformation on the microstructure and mechanical properties of pure magnesium have been investigated. The results show that the fine and uniform equiaxed grain with 7.9 μm in average diameters in the pure magnesium can be generated, and its mechanical properties at room temperature are equivalent to that of T6 treated WE43AMB magnesium alloy, by squeezing casting at 150 MPa and squeezing deformation with squeezing ratio of 10.关键词：Pure Magnesium;Squeezing Casting;Squeezing Deformation;Refinement Reinforced;Mechanical Properties
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发布时间：2023-12-18 - 摘要：The solidification simulation for HSi80-3 silicon brass rudder bonnet by the Procast software has been conducted based on two kinds of gating systems to investigate the potential shrinkage hole （porosity） position in the castings. The results show that the severe shrinkage hole in the main body of the rudder bonnet can be visualized by using the first filling process while the shrinkage hole （porosity） can be effectively eliminated by the second filling process due to order solidification from top to bottom. Based on above simulated results, the second filling process was adopted, and production verification has been conducted. The results show that the defects, including shrinkage hole （porosity）, can be eliminated by adopting second filling process, showing the availability of solidification.关键词：Silicon Brass;Filling;Temperature Field;Solidification Simulation;Process
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发布时间：2023-12-18 - 摘要：Based on the requirements of real-time monitor for hot-exerted state of mould in continuous casting, a 2D model for horizontal section of mould copper plate was established, in which a numerical algorithm based on the least square method for inverse heat conduction problem was developed. Using above model, the program is written by the VC++6.0 software, where discrete equations were built up by the FVM with varying band width and Cholesky decomposition technique to improve computation speed. The availability of the 2D model has been verified by comparing with calculated results from commercial softwares, and the reliability of algorithm and program was validated by analyzing experimental data, which provided an applicable method to monitor the solidification process by numerical simulation.关键词：Continuous Casting Mould;Inverse Heat Conduction Problem;Heat Flux
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发布时间：2023-12-18 - 摘要：The influence of RE Y on morphology of primary phase in A356 semi-solid aluminum alloy prepared by the low under-cooled pouring method has been investigated. The factors influencing morphology of primary phase in semi-solid A356 aluminum alloy slurry were optimized by orthogonal design. By intuitional and square difference analysis, the primary phase with shape coefficient of 0.7 and equal-area-circle diameters of 49.6μm in the semi-solid A356 aluminum alloy slurry can be observed with 0.3% Y addition and filling at 595 ℃ for 3 min. The dominant influential factors are pouring temperature with the reliability of 95%, then the Y content and holding time.关键词：RE Element Y;Semi-solid;A356 Aluminum Alloy;Primary Phase;Orthogonal Design
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发布时间：2023-12-18 - 摘要：The ZF16 contact pedestal used in high voltage switch by hot extrusion was experimentally manufactured. The new processing procedure in hot extrusion is chosen as follows: materials cutting---heating---converse extrusion---punching---heating---extrusion. Compared with conventional machining process, the technology of first forward-extrusion and second extrusion has the advantages of low material-consumption, high efficiency and significant economic profits in production of ZF16 contact pedestal used in high voltage switch.关键词：Contact Pedestal;Hot Extrusion;Red Copper;High Voltage Switch
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发布时间：2023-12-18 - 摘要：The die casting die with special structure for aluminum alloy thin disk was designed, and the structure features and operating principle of the die were described. The center sprue was adopted in the die, and the core for forming hole-through of the castings was taken as diverter also. The runner was set the inner-wall near towards the die hole, which is favorable for cutting by punching method and dose not affect the size and appearance of the disk. Two stages mold unloading mechanism with the cavity plate and ejector pin controlled by two pendulum bars were designed to avoid the breakage of the disk resulting from the high unloading resistance. The die casting die has the features of simple structure, reliable running performance and convenient operation as well as excellent casting quality.关键词：Die Casting Die;Center Sprue;Unloading Mechanism;Pendulum Bar;Thin Disk
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发布时间：2023-12-18 - 摘要：The processing parameters relationship and control method of electromagnetic low pressure casting for aluminum alloy have been investigated. The relationship between electromagnetic driving force and electric current as well as flux volume and electric current, and its mathematical model have been determined by experiment and mathematical analyses. Meanwhile, the properties of castings in electromagnetic low pressure casting and in conventional low pressure casting have been compared. It is found that the aluminum liquid flux volume of electromagnetic low pressure casting presents a strictly linear relation with the electrode current with a given magnetic inductivity. With a given electrode current, the aluminum liquid flux volume can be decreased with raising the height of liquid aluminum alloy outlet, which is helpful for improving the properties of electromagnetic low pressure castings. The accuracy of control process in electromagnetic low pressure casting is obviously superior to that in conventional low pressure casting.关键词：Aluminum Alloy;Electromagnetic Low Pressure Casting;Technology Experiment;Application
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发布时间：2023-12-18 - 摘要：The running principle of squeezing casting mould with bi-parting surface was described systematically. The problems existed in the mould with bi-parting surface have been discussed, including getting and pouring liquid metal, separating remains from the sprue, setting leader and determining the length of leader. Given-distance parting mechanism in the mould with bi-parting surface was designed including pendulum-hooked parting, spring parting and given-distance leader parting. The production in practice has verified that the pendulum-hooked parting mould is suitable for the components with large diameter center runner, while the spring parting mould and given-distance lead parting mould suitable for ones with small diameters center runner.关键词：Squeezing Casting;Bi-parting Surface Mould;Given-distance Parting;Center Runner
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发布时间：2023-12-18 - 摘要：The features of sodium silicate shell mold, compound shell mold, mid-temperature wax-sol silicate colloid shell mold and low-temperature wax-sol silicate colloid shell mold have been compared. It is pointed out that the low-temperature wax-sol silicate colloid shell mold is suitable for the investment castings with common quality requirements, while mid-temperature wax-sol silicate colloid shell mold suitable for the small or super-small investment castings with high quality requirements. The key produce process is described in using low-temperature wax-sol silicate colloid shell mold.关键词：Low-temperature Wax;Sol Silicate Colloid;Shell Mold;Investment Casting
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发布时间：2023-12-18 - 摘要：A method combined ANN （artificial neural network） with PSO （particle swarm optimization algorithm） to optimize the processing parameters of QSn6.5-0.1 horizontal continuous casting has been put forward taking seven main casting technological factors as optimizing parameters, and ratio of accepted products as optimizing objective. Through the orthogonal experiment of the technical factors in the casting process, the mapping model of ANN was established based on the data from above experiment. Through optimizing the model by PSO, the optimized processing parameters have been given. A learning algorithm of subtractive clustering method （SCM） was used for radial basis function （RBF） network to get parameters RBF with the help of the least-square method （LSM）, and a tactics which alters the weight dynamically according to particle position and objective function values is applied to modify the PSO. Practical production verifies that it increases the ratio of accepted products from 56% to 71%.关键词：QSn6.5-0.1;Horizontal Continuous Casting;Processing Parameters;ANN;PSO
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发布时间：2023-12-18 - 摘要：Three-dimensional molding, mould design, production of white-pattern, adhesion of pattern layer, brushing coating and pouring of T-5011 396 cylinder cover of the Bendix Tu-Flu 500&750 compressor have been expounded. The developing period of the mould can be shortened and the modified ability can be improved by visualizing the product structure and mould design using computer simulation. The cavity in the pattern can be effectively filled with the small bead with good fluidity. The deformation and location-fixed of cylinder cover can be greatly eliminated by means of lost foam casting.关键词：Lost Foam Casting;Mould Design;Cylinder Cover
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发布时间：2023-12-18 - 摘要：The microstructure and mechanical properties of the composite coating deposited on the electrode surface by a vibrating electro-sparking deposited process have been characterized by X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis, micro-hardness tests and welding experiment. The results show that coating is composed of TiC, Cu and CuNi2Ti, characterized by splashed pit and crack in surface,which exhibits desirable metallurgical bonding between coating and the matrix. The micro-hardness of composite coating reaches 1 144 with 1 N loading. Compared with that of coating free electrode, the service life of ones by electro-sparking deposited composite coating can be increased by 2.4 times.关键词：Electro-sparking Deposition;Composite Coating;TiC;Spot Welding Electrode
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发布时间：2023-12-18 - 摘要：Effects of Si content and modification on microstructure and properties of in-situ Mg2Si/Mg composites prepared with Mg-Si binary alloy have been investigated. The results reveal that with increasing the Si content, the fluidity of Mg-Si alloy is decreased, resulting in the increase of in-situ Mg2Si particles in the composites and the generation of more developed dendrite, such as Chinese script. Although the modification of optimized Mg-8Si alloy with MM（mistchmetal） and Sb respectively all can improve the distribution and shape of Mg2Si particle, the modification effect with Sb is obviously superior to that with MM. With addition of 1.2% Sb, the Mg2Si particle can be transformed from the Chinese script to uniformly dispersed particles in the composites, greatly improving the wear resistance of the composites.关键词：Si;Modification;Mg2Si/Mg Composites
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发布时间：2023-12-18 - 摘要：TiB2/CuCrZr composites have been successfully prepared by liquid-liquid in-situ synthesis , and the effects of TiB2 content on hardness and electric conductivity of the composites have been examined. The results reveal that the hardness of composites exhibits the trend of initial increase and then decrease with the increase of TiB2 content, observing the maximum hardness ,HV 206, with 3% TiB2 content. Electric conductivity of the composites is slightly dropped with the increase of TiB2 content.关键词：Liquid-liquid Reaction;Cu Matrix Composites;In-situ Synthesis;TiB2
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发布时间：2023-12-18 - 摘要：Co-Al2O3 cermet was prepared by combustion synthesis , in which diluent Al2O3 and reactive agent TiO2 was added to control the combustion synthesis reaction process. Meanwhile, the effects of diluent Al2O3 and reactive agent TiO2 on microstructure of cermet have been approached. The hollow Co-Al2O3 cermet parts with fine and uniformly distributed metal phase in the Al2O3 matrix is successfully prepared by controlling initial reactive temperature of thermo-explosive reaction at about 1 050 K using Al-Fe2O3 assistant system.关键词：Al-CoO System;Combustion Synthesis;Cermets;Microstructure
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发布时间：2023-12-18 - 摘要：SiCp particulate reinforced magnesium matrix composites SiCp/AZ91 with low porosity and uniformly distributed particles were successfully prepared by semi-solid stirring. The effects of processing parameters, such as stirring velocity, particle size, rotation direction of propeller stirrer, particle pretreatment, on uniform distribution of the particles in the composites have been investigated. The results show that pretreatment has the dominant effect on the uniform distribution of the particles. High temperature pre-oxidized treated SiC particle can effectively improve interface bonding between particle and the magnesium alloy matrix and promote the uniform distribution due to its better wettability with the matrix alloy. With given other parameters, the larger the particle diameters are, the more uniform distribution the particle is; the lower the stirring speed is, the more uneven distribution the particle is. In addition, with the size of the particle less than 50 μm, the rotation direction of the impeller stirrer is a significant parameter for uniform distribution of the particles. The optimized processing parameters are determined as follows: ascending propeller stirrer, holding temperature of 580 ℃, stirring speed at 400 r/min, particle size of 50 μm and volume fraction of particle in the matrix of 15%.关键词：Semi-solid Stirring;Magnesium Matrix Composites;Processing Parameters;Uniform Distribution of Particles
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发布时间：2023-12-18 - 摘要：Cu-Al2O3 composites with different oxygen resource coefficients were prepared by a new simplified internal oxidation technique. The microstructure of the composites was observed by SEM （scanning electronic microscope） and TEM （transmission electronic microscope）. The results show that amounts of fine γ-Al2O3 particles with 520 nm in diameters and about 2560 nm in spatial distance among particles are dispersively distributed into the Cu matrix, verifying the successful preparation of the Cu-Al2O3 composites. The internal oxidation of compressed Cu-Al alloy powder is fully completed with the oxygen resource coefficient of 1.20 after sintering at 950℃ for 4 hours, which reveals the optimum oxidant content for internal oxidation is oxygen resource coefficient of 1.20.关键词：Cu-Al2O3 Composites;Internal Oxidation;Oxygen Resource Coefficient;Orientation Relationship
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发布时间：2023-12-18 - 摘要：Effects of rotating magnetic field and Ce modification on solidification structure of eutectic Sn-Bi alloy have been observed. It is found that rotating magnetic filed can obviously refine the grain size in alloy and improve the structure in hypoeutectic Sn-55Bi due to restrain the growth of primary phase Sn, while rotating magnetic field can eliminate the uneven structure distribution in Sn-65Bi alloy, however, it can little affects on refining Bi primary phase. The growth of primary phase Bi can be sharply restrained to result in the obvious refinement of bulk Bi phase by exerting rotating magnetic field on hypereutectic Sn-65Bi alloy with 1% Ce modification, which is attributed to the co-action of rotating magnetic field and Ce modification.关键词：Rotating Magnetic Field;Sn-Bi Eutectic Alloy;Ce;Grain Refinement
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发布时间：2023-12-18 - 摘要：Mg65Cu22Ni3Y10-xNdx bulk amorphous alloys with x of 0,2,4,5,6,8 were successfully prepared by the wedge-shaped copper mold method. Effects of Nd on glass forming ability （GFA） and thermal stability of Mg65Cu22Ni3Y10 bulk amorphous alloy have been investigated by XRD and DSC. The experimental results reveal that 2% or 4% Nd addition （atom） can improve both glass forming ability and thermal stability of the alloy, with 2% Nd addition, the highest undercooled liquid region （61.5K） and thermal stability are observed. With 5% Nd addition, although the narrowest under-cooled liquid region occurs in the alloy, the best GFA such as approximately temperature of 0.568 and critical thickness, such as 3.8 mm, can be observed. However, with the Nd addition more than 5%, the GFA of the alloy is declined.关键词：Nd;Mg65Cu22Ni3Y10 Bulk Amorphous Alloy;GFA;Thermal Stability
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发布时间：2023-12-18 - 摘要：Effects of Ce modification time and content on microstructure of eutectic Al-Si alloy have been investigated. The results show that with Ce modification, eutectic Si phase in the eutectic Al-Si alloy is converted from long needle to rosette. Modification time and content of Ce have the significant effects on grain refinement in the eutectic Al-Si alloy. The desirable modification effects can be observed with 1% Ce addition for 6090 min.关键词：Ce;Eutectic Al-Si Alloy;Modification;Microstructure
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发布时间：2023-12-18 - 摘要：Effects of holding time and sequence of adding halide salt on formation of second phase particles in as-cast Al-Ti-B master alloy have been investigated. With postponing the holding time, the TiAl3 particle grows with more uniform distribution in the Al matrix and trending towards the same size. For three kinds adding sequence of halide salt, the maximum TiAl3 particle size can be observed with firstly adding B salt then Ti salt, while the minimum TiAl3 particle size occurs in the master alloy with adding mixed salt. Major TiB2 particles are distributed into the boundary of α-Al phase with the minor on the surface of TiAl3 particle. The effects of holding time on distribution of TiB2 particles can be ignored.关键词：Al-Ti-B Master Alloy;Holding Time;Sequence of Adding Halide Salt;Second Phase Particle
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发布时间：2023-12-18 - 摘要：Effects of high intensity ultrasonic on solidification of Al-1Si alloy have been observed by optical microscope and EPMA, and the latent heat of fusion is measured by DSC. The influencing mechanism of ultrasonic cavitation and acoustic stream on solidification structure in the Al-1Si alloy has been approached. The results show that it is decreased by 34μm from 94 μm in average grain size of the alloy, and by 159.81J/g from 236.90J/g in the latent heat of fusion of the alloy after ultrasonic treatment, which reveals that the high intensity ultrasonic can remarkably improve the homogenization of the constituent and refine the grain size in the alloy.关键词：High Intensity Ultrasonic;Al-1Si Alloy;Grain Refinement;Latent Heat of Fusion
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发布时间：2023-12-18 - 摘要：A new high strength ZL210A aluminum alloy was developed based on the Russian ВАЛ10 alloy through optimizing compositions and smelting, heat treatment specification as well as mechanical properties. The results show that the ZL210A alloy is superior to ВАЛ10 alloy in properties and equivalent to ZL205A alloy in ambient tensile property but superior to ones in fatigue resistance properties, meanwhile,its composition, smelting process, heat treatment are suitable for the practical production at home, showing prospect application future in space, automobile and so on.关键词：ZL210A Alloy;Cast Alloy;Mechanical Properties
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发布时间：2023-12-18 - 摘要：Due to difficulty in casting process for production of abnormal shape aluminum castings, the practical experiences and computer solidification simulation are relied on. The casting process for some typical parts, such as tube body, wheel, impeller, has been described. Through analyzing the casting processes for the typical parts, the casting technologies for large abnormal shape aluminum alloy have been refered.关键词：Aluminum Alloy;Large Abnormal Castings;Processing Design
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发布时间：2023-12-18 -
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