低过热度铸造半固态LY12铝合金二次加热的组织演变规律

采用低过热度铸造法制备半固态LY12铝合金坯料,研究了坯料在二次加热过程中的组织演变规律以及升温速率和加热温度对坯料二次加热组织的影响.结果表明:随着坯料温度的升高和保温时间的延长,坯料组织首先发生成分均匀化,然后部分重熔,晶粒通过合并和Ostwald熟化而逐渐长大和球化.提高升温速率,可适当抑制晶粒的长大.有利于获得...

Microstructure evolution of reheating semisolid LY12 aluminum alloy billet prepared by low superheat casting

Semisolid LY12 aluminum alloy billets were prepared by low superheat casting method.The microstructure evolution of billets during reheating and the effects of heating rate and heating temperature on reheating microstructures of billets were investigated.Results showed that with the rising of temperature and prolonging of holding time,the microstructure composition homogenization first occurred,and then followed by partial remelting and gradual growing up and globurizing of grains by small grain merging and Ostwald ripening.The increase of the heating rate could suppress appropriately the growth of grains,which was helpful to gain finer grains.The increase of heating temperature could obviously accelerate the formation of liquid phase between grains,and Ostwald ripening,helpful to get rounder grains and speed up reheating effect of the billet.