Effects of SiC Particle and Holding Time on Semi-Solid Microstructure of SiCP/AZ61 Composites
Effects of SiC particle and holding time on microstructure evolution of SiCP/AZ61 composites during semi-solid isothermal heat treatment method were studied, and evolution mechanism of semi-solid microstructure of composites was discussed. The results indicated that the process of microstructure evolution of SiCP/AZ61 composites by the isothermal holding at the temperatures of 595°C for different times (0min~90min) experienced in succession the rapid merging of the secondary dendritic arms →large massive structure→melting and separating of the local grain boundary →spheroidization of the gains →slowing growth of globular microstructure. Synthetically, after isothermal holding at 595°C for 30min to 60min the favorable semi-solid microstructure can be obtained; Compared with the monolithic AZ61alloy, microstructure of SiCP/AZ61 composites during semi-solid isothermal heat-treatment was finer as a result of entering of Sic particle, and with the increasing of SiC particle volume fraction, globular gain size was smaller.
Zhengyi Jiang, Jingtao Han and Xianghua Liu
F. Y. Zhang et al., "Effects of SiC Particle and Holding Time on Semi-Solid Microstructure of SiCP/AZ61 Composites", Advanced Materials Research, Vols. 152-153, pp. 628-633, 2011