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Grain Size Control of Semisolid A356 Alloy Manufactured by Electromagnetic Stirring 被引量:23
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作者 P.K.Seo C.G.Kang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第2期219-225,共7页
To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carri... To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carried out. It was found that in the early period of solidification, the dendrite breakages led to a fine primary phase. When dendrites grew coarsely, the effect of ripening on grain size overwhelmed that of dendrite breakage. It was also found that the high cooling rate favored large nucleation rate, and led to a fine primary phase. But high cooling rate also made the growth rate of the dendrite arm, which prevented the dendrite arm from being sheared off. Therefore there were a suitable stirring time and suitable cooling rate to obtain the best rheo die-casting structure. Qualified semisolid A356 aluminum alloy was successfully manufactured with short time EMS. 展开更多
关键词 semisolid metal process Electromagnetic stirring Rheo die-casting Grain size control
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Effect of Process Factors on Microstructure of Semisolid Continuous Casting Billets 被引量:1
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作者 Shuming Xing, Qijie Zhai, Hanqi Hu ( Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China School of Material Science and Engineering, Shanghai University, Shanghai 200072, China Material Science and Engineering School, Univer 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2000年第4期242-245,共4页
Semisolid continuous casting (SSCC) is a new technology to produce billets for semisolid metal forming (SSMF). The effect of process factors, such as pouring temperature, stirring rate, preheating temperature and ther... Semisolid continuous casting (SSCC) is a new technology to produce billets for semisolid metal forming (SSMF). The effect of process factors, such as pouring temperature, stirring rate, preheating temperature and thermal conductivity of stirring chamber, on the microstructure of SSCC billets was studied by means of the factorial experimental method. The results show that the microstructure of SSCC billets can be controlled by the above-mentioned four process factors. In order to obtain fine and rounded granular grains in an SSCC billet, the pouring temperature, preheating temperature and stirring rate should be kept in a moderate range, and the thermal conductivity of stirring chamber should be high. The regression equations with the process factors connecting the microstructure was also set up based on experimental data. 展开更多
关键词 semisolid metal continuous casting process factors microstructure Metallurgy
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Semisolid lead-antimony alloys for cars batteries
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作者 A.POLA M.GELFI +1 位作者 M.M ODIGELL R.ROBERTI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1774-1779,共6页
The application of semisolid process was investigated on Pb-Sb alloys that are normally used for metallic parts in car batteries, in order to increase their mechanical properties and corrosion resistance.The semisolid... The application of semisolid process was investigated on Pb-Sb alloys that are normally used for metallic parts in car batteries, in order to increase their mechanical properties and corrosion resistance.The semisolid behaviour of a Pb-4%Sb alloy was analysed by means of rheological and calorimetry differential scanning experiments.The alloy was melted, treated by ultrasound to obtain the semisolid state and then poured into permanent moulds.Some of these samples were also heated in semisolid temperature range and injected in thixo-casting apparatus.Both poured and injected samples were characterized by metallographic analysis, mechanical test and electrochemical corrosion experiments.The results show an improvement of mechanical and corrosion resistance with respect to samples obtained by conventional casting technique. 展开更多
关键词 Pb-based alloys semisolid metal corrosion resistance VISCOSITY
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Segregation of Liquid Phase in the Extruded Semisolid Metal
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作者 Zhao YANG,Haifeng ZHANG,Aiming WANG,Bingzhe DING Zhuangqi HU Shenyang National Lab.for Materials Science,Institute of Metal Research,Chinese Academy of Sciences, Shenyang 110016,China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第3期209-212,共4页
The influence of stress and strain on the solid/liquid segregation formed in deformed semisolid metal was studied.Thecompression experiment at a low constant strain rate was conducted on a Gleeble 1500 thermo-mechanic... The influence of stress and strain on the solid/liquid segregation formed in deformed semisolid metal was studied.Thecompression experiment at a low constant strain rate was conducted on a Gleeble 1500 thermo-mechanical sireulator.The stress and strain fields of the samples were calculated by finite element method.The experiment results and themodeling results prove that the hydrostatic pressure gradient is the driving force for solid/liquid segregation.Thesegregated liquid phase usually agglomerates in the micropores and shear bands are created by sliding of equiaxeddendrite grains.The sliding among the grains is influenced by the solid fraction and grain size of the semisolid slurry,so as the solid fraction and grain size change,the morphology of the segregated liquid changes. 展开更多
关键词 semisolid metal Solid/liquid segregation Hydrostatic pressure Sliding of grains
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Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process 被引量:5
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作者 Wang Shuncheng Cai Chang +1 位作者 Zheng Kaihong Qi Wenjun 《China Foundry》 SCIE CAS 2013年第5期299-303,共5页
The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo... The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 ℃ When the round billet is reheated at 600 ℃ for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties. 展开更多
关键词 semisolid metal THIXO-FORGING low superheat casting aluminum alloy wheel
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Observation of interface of two kinds of bi-metal composite parts prepared by thixo-forging 被引量:4
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作者 杨昭 周丽 董建雄 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1579-1584,共6页
Two kinds of bi-metal composite parts (Sn-15%Pb and Pb-22%Sn bi-metal system, and Al-7%Si and SiCp/6061 MMC bi-metal system) were prepared by the strain-induced melt activated thixo-forging. The interfaces of the bi... Two kinds of bi-metal composite parts (Sn-15%Pb and Pb-22%Sn bi-metal system, and Al-7%Si and SiCp/6061 MMC bi-metal system) were prepared by the strain-induced melt activated thixo-forging. The interfaces of the bi-metal composites were observed by OM and SEM. The observations show that the semisolid metals keep independence during thixo-forging. The solid phases in the semisolid slurries maintain their original morphologies after thixo-forging. The liquid phases near the interface mix together and form a thin layer. The interfaces are bonded firmly with the metallurgical bonding. No oxide layers are found at the interfaces. Strengths of the interfaces were investigated by the micro-hardness test. The experimental results show that the composite interfaces have high strength. However, the agglomerated enhancing particles cause fine defect on the interface of the Al-7%Si and SiCr/6061 MMC bi-metal composite. 展开更多
关键词 semisolid metal processing bi-metal composite thixo-forming die-forging metal matrix composite
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Microstructural Evolution of Solid-solution-treated Zn-22Al in the Semisolid State 被引量:4
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作者 M.A.M.Arif M.Z.Omar +2 位作者 N.Muhamad J.Syarif P.Kapranos 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2013年第8期765-774,共10页
The effect of solid-solution-treatment on the semisolid microstructure of Zn-22Al with developed dendrites was investigated. Forming Zn-22Al products by semisolid metal processing offers significant advantages, such a... The effect of solid-solution-treatment on the semisolid microstructure of Zn-22Al with developed dendrites was investigated. Forming Zn-22Al products by semisolid metal processing offers significant advantages, such as reductions in macro-segregation, porosity and forming costs. Thermal and rnicrostructural analyses of the formed Zn-22Al alloy were performed by differential scanning calorimetry, scanning electron microscopy and optical microscopy. The changes in the microstructures and phase transformation in response to various solid- solution-treatments were analysed. In this study, as-cast samples were held isothermally at 330 ℃ for 0.5- 5 h and then partially remelted at a semisolid temperature of 438 ℃ for 1 h to produce a solid-globular grain structure in a liquid matrix. A non-dendritic semisolid microstructure could not be obtained when the traditionally cast Zn 22Al alloy with developed dendrites was subjected directly to partial remelting. After solid-solution-treatment at 330 ℃, the black interdendritic eutectics were dissolved, and the dendritic structures gradually transformed into uniform β structures when the treatment time was increased. The coarsened and merged dendrites were separated as a result of penetration by the liquid phase and melting of the residual eutectic at sites along the former grain boundaries. The microstructure of the solid-solution- treated sample transformed into a small globular structure; the best shape factor of 0.9, corresponding to a particle size of 40 ± 16 μm, is achieved when the sample was treated for 3 h followed by direct partial remelting into its semisolid zone. 展开更多
关键词 semisolid metal processing SOLIDUS LIQUIDUS DENDRITIC Spherical morphologies
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