固液混合铸造Al-Mn合金坯料的重熔处理

Remelting Treatment on Al-Mn Alloy Blanks Prepared by Solid-Liquid Mixed Casting Technology

采用固液混合铸造技术制备了A l-Mn合金坯料,对坯料进行了重熔水淬处理。对合金显微组织和硬度的研究表明,重熔处理后A l-Mn合金中析出的A l6Mn相圆整、均匀,且随着重熔温度的升高,析出相尺寸变大;并且A l-20Mn合金的硬度由固液混合铸造的91HB增加到重熔处理后的193HB。在重熔初期,A l-Mn合金中粗大的析出相能有效地碎裂、细化,因此重熔处理可成为改善A l-Mn合金组织和固液混合铸造触变成形的重要工艺环节。

The solid-liquid mixed casting technology was used to prepare Al-Mn alloy blanks, which were then reheated to semisolid state and quenched in water in order to study their microstructures and hardness. The results show that the A16Mn phase separated from the reheated Al-Mn alloys is near-spherical and uniformly distributed. With increasing of the reheating temperature,the size of precipitated phase increases. The hardness of these alloys increases from 91HB of solidliquid mixed casting blanks to 193HB of reheated ones. At the beginning of the reheating process,the coarse precipitated phases can be smashed to fine particles. So reheating process can be an important route to improve Al-Mn alloy microstructure and a key step of thixoforming process of solid-liquid mixed casting technology.