Microstructural evolution of A356.2 alloy prepared by the SIMA process

Cross wedge rolling is introduced into the strain induced melt activation process before cold compression to prepare semisolid A356.2 alloy. The microstructural evolution of semisolid A356.2 alloy under as-rolled and as-deformed conditions has been investigated. The results show that the microstructure of as-rolled A356.2 alloy after partial remelting consists of predominantly elongated and aggregated solid particles along the rolling direction. Higher compression deformation for as-deformed A356.2 alloy can result in finer solid particles distributed in the liquid matrix and improve spheroidization of these particles. After the solid particles are separated into finer ones due to liquid penetration, Ostwald ripening plays the key role in particle coarsening. The current coarsening rate constant is 412 μm ³ s ^{- 1} at 580°C.