Papers by Author: Xiu Yan Guo

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Authors: Shi Kun Xie, Xiao Qiu Zheng, Rong Xi Yi, Xiao Liang Pan, Xiu Yan Guo
Abstract: SSM(Semi-solid metal) forming has been developed to become a novel technology in the 21st century for the formation of near net shape components, competing with conventional casting and forging technologies. In this paper, the casting microstructure and its change during remelting of AlSi7Cu5 alloy casting by slope near-liquidus method were researched. Experiments show that it has a significant impact on microstructure by cooling method, the thermal conductivity of the casting mold and casting method. The microstructure of AlSi7Cu5 alloy obtained by slope near-liquidus method at 600°C is uniform and small equiaxed Its average grain diameter is about 55.2um, and its average grain size roundness is about 2.13. The reheated microstructure which can be applied in thixo-forming preferable will be obtained by keeping constant temperature 25min at 580°C.
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Authors: Shi Kun Xie, Rong Xi Yi, Zhi Gao, Xiang Xia, Cha Gen Hu, Xiu Yan Guo
Abstract: The effects of adding rare earth Cerium on Al-4.5Cu alloy microstructure, solidification range and volume changes in the solidification process are researched. Experiments show that rare earth Cerium will bring remarkable effects on the alloy microstructure, solidification and solidification shrinkage interval. When the quantity of rare earth Cerium is about 4 wt%, the solid-liquid two phase of Al-4.5Cu alloy will range from 640°C to 600°C. The grains of the alloy are refined, round. The volume shrinkage is only 68.6% of that without adding rare earth Cerium.
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Authors: Shi Kun Xie, Rong Xi Yi, Xiu Yan Guo, Xiao Liang Pan, Xiao Qiu Zheng
Abstract: In semi-solid remelting process, the various stages of reheating temperature and isothermal holding time must be accurately controlled in order to obtain the uniformly distributed and small equiaxed grains microstructure. In this paper, a temperature control program was developed and the remelting process for Al-7Si-2RE aluminum alloy was carried out. The results showed that with the raise of reheating temperature and the extension of isothermal holding time, the liquid fraction increases, α-phase grain grows and becomes rounding in the process of Al-7Si-2RE alloy semi-solid remelting. The most reasonable process parameter of reheating temperature is at 585~590°C and its appropriate isothermal holding time are about 10~15min for the semi-solid Al-7Si-2RE alloy.
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Authors: Rong Xi Yi, Shi Kun Xie, Xiao Qiu Zheng, Zhi Gao, Xiu Yan Guo, Xiao Liang Pan
Abstract: Al-4.5Cu-3Ce alloy semi-solid slurry has been prepared by using slope vibration casting. The effects of the pouring temperature, slope length, vibration amplitude and vibration voltage on alloy solidification microstructure were researched. Experiments show that these parameters play a significant role on the alloy microstructure. The uniform, small equiaxed microstructure of Al-4.5Cu-3Ce alloy can be acquired by water-cooled copper mold casting at 680°C with slope length of 20cm, vibration amplitude of 2cm and vibration voltage of 80v. Its average grain diameter is 28.1um with average roundness coefficient of 0.82.
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Authors: Rong Xi Yi, Xiao Qiu Zheng, Shi Kun Xie, Xiu Yan Guo
Abstract: The influences of heating temperature and holding time on the microstructures were investigated during the semi-solid remelting process of rare earth Al-4.5Cu alloy. The evolution mechanism of crystal organization was discussed. Experiments show that the heating temperature and holding time are very important to the grain size and uniformity. It is the most suitable parameters, as heating temperature is 630°C and holding time is 20 minutes, to remelting process. During the remelting process, grain mergering and Ostwald growing up is the main mechanism of change on microstructures.
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