Microstructure evolution of semi-solid Mg2Si/A356 composites during remelting process

The semi-solid processed Mg2Si/A356 composites were fabricated using a sloping plate,and the phase and morphology evolution of the semi-solid Mg2Si/A356 slurry during the remelting process was investigated.Results indicate that compared to as-cast microstructure,the size of primaryα-Al phase and Mg2Si phase of semi-solid microstructure fabricated by using a sloping plate decreases and the morphology ofα-Al phase becomes fine and globular.With increasing the reheating temperature and prolonging the holding time,the primaryα-Al phase spheroidizes,the liquid fraction in semi-solid microstructure increases,and the Chinese script Mg2Si phase embedded in the primaryα-Al phase cannot be observed.The Chinese script Mg2Si phase is distributed in the secondaryα-Al phase and becomes smaller.The net-shaped eutectic phase also becomes finer after reheating.The optimum remelting parameters suitable for thixoforming in this study are remelting at 580℃for 30 min.