Papers by Author: Rong Xi Yi

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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: Rong Xi Yi, Shi Kun Xie, Xiao Qiu Zheng, Yong Ping Ai
Abstract: The semi-solid slurry of AlSi7 alloy was prepared by near-liquids cast processing. The effects of different content of RE on the cast performance and the semi-solid remelting performance in AlSi7 alloy was researched. The results indicated that adding RE will widen the AlSi7 alloy solid-liquid two-phase zone temperature and refine the grains, silicon will obvious metamorphoses. The best amount of RE is about 0.5%. Its semi-solid remelting organization is equilateral globular grains.
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Authors: Xiao Qiu Zheng, Shi Kun Xie, Rong Xi Yi
Abstract: In order to research the adhesion of sputtering protective coating of Gd.Gd substrates were differently coated with Cu and Al by means of DC magnetron sputtering technology. The characteristics of the films were investigated by scanning electron microscopy (SEM), EDS, and the adhesions of films were tested by tension test. The results show that the films of Al are smooth and perfect, the interferences between Al and Gd join together strongly, and the largest strength of adhesion is 27.6MPa in these tests on the optimize parameters through orthogonal experimental design. While the films of Cu are rough and bad, the interferences between Cu and Gd join together loosely, and the largest strength of adhesion is only 3.02MPa in these tests on the optimize parameters through orthogonal experimental design.
633
Authors: Shi Kun Xie, Rong Xi Yi, Xiao Qiu Zheng, Zhi Gao, Xiang Xia
Abstract: The fabrication process of refined isometric crystals of semi-solid Al7Si2RE alloy is discussed, and the remelting microstructure of Al7Si2RE alloy with isothermal holding at 580°C is also researched. Experiment shows that the casting temperature, the casting size, the casting mold and the casting method will make great effects on the fabrication of refined isometric crystals alloy microstructure. Slope copper mold casting at liquidus temperature can be used in preparing excellent non-dendritic microstructure billet; its remelting microstructure is uniform, refined isometric crystals with the average diameter of 44.2um and the average roundness of 2.08.
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Authors: Xiu Yan Guo, Guo Jin Ma, Shi Kun Xie, Rong Xi Yi
Abstract: Cu-4%C mixed-powder consisting of rough copper powder and graphite powder was separately mechanical alloyed by high energy ball milling. The phases and micrograph of these powders were determined by X-ray diffraction and scanning electron microscopy (SEM). The results show that increase of the lattice parameter of copper with milling times, up to a saturation value of about 24h; The absence of graphite reflections in X-ray diffract grams for longer milling times.
1049
Authors: Rong Xi Yi, Wen Xian Huang, Zhao Hui Liu, Shi Kun Xie
Abstract: The semi-solid microstructure of ZL101 alloy was fabricated by technology of vibrating inclined cast. The effections of length of slope and vibration voltage on microstructure were also investigated. The experimental results showed that two parameters played an important role on the microstructure of ZL101 alloy. The homogeneous, small and rounded sphere-like semi-solid equiaxed crystals were obtained when the ZL101 alloy was cast in water-cooled copper mold with 25cm slope length at 640 °C and 60v vibration voltage, the average grain diameter and shape factor of which was 26.5um and 0.8, respectively.
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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: Xiao Qiu Zheng, Shi Kun Xie, Rong Xi Yi
Abstract: In order to research the adhesion of sputtering protective coating of Gd. Gd substrates was coated with 1Cr18Ni9Ti by means of DC magnetron sputtering technology. The characteristics of the film were investigated by scanning electron microscopy (SEM), EDS, SPM and the adhesions of film was tested by tension test. The results show that the films of 1Cr18Ni9Ti are distributed by means of islands when the sputtering was initiated and the grains are like thin fiber. After a few minutes, the films are smooth and perfect, the interferences between 1Cr18Ni9Ti and Gd join together strongly, and the largest strength of adhesion is 24.7MPa when the sputtering density is 966 w/cm2 and the sputtering time is 8 minutes.
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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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