Semi-solid characteristics and thixoforming of hypereutectic Al-Si alloy

Effects of processing parameters on microstructure evolutions by mechanical stinting, procedures for obtaining thixotropy in semi-solid slurries, and procedure for thixoforging component, were investigated in hypereutectic AI-S alloy. It is shown that 605 degrees C was the proper temperature for stirring treatment of this alloy, at which the coarse and plate primary Si crystals were effectively changed to globular crystals with a mean diameter of 200 mu m after 50 min stirring, that billets with excellent thixotropy were obtained after 50 min remelting at 575 degrees C, in which solid fraction of matrix and primary Si crystals was about 60%, and that a perfect near net shape component of disc casting was obtained by thixoforging.