A2017半固态合金二次加热工艺及组织演化机制  

Reheating Process and Microstructure Evolution Mechanism of the Semi-solid A2017 Alloy During Reheating in Semi-solid State

作　　者：王顺成[1] 温景林[1] 陈彦博[1] 曹富荣[1] 李英龙[1] 

机构地区：[1]东北大学材料与冶金学院,辽宁沈阳110004

出　　处：《铸造》2004年第8期590-594,共5页Foundry

基　　金：国家自然科学基金;上海宝钢集团公司联合资助(50274020)。

摘　　要：相同加热温度条件下,随着保温时间的延长,晶粒逐渐长大和球化,液相分数增加;提高二次加热温度,晶粒长大和球化速度加快。在620～625℃加热,保温40～60min,可获得由均匀球形晶粒悬浮于液相组成的半固态组织,晶粒大小为70～90μm,液相率为40%～45%。而常规铸造枝晶A2017合金坯料二次加热后仍然保留粗大的枝晶网络结构。半固态合金锭坯二次加热初期晶粒的熔合合并是晶粒长大的主要方式,相界面能的升高和相界面表面张力是组织演化的主要驱动力。The semi-solid A2017 billets provided with shearing-cooling-rolling (SCR) process were reheated. The reheating process and the mechanism of microstructure evolution were researched. The results indicated that the mean diameter of grains increases with the prolongation of isothermal holding time, with grains sphericized more and more and liquid fraction increased. In addition, the grains grow up and are sphericized faster as the reheating temperature is rising. Under the combination of reheating temperature 620～625℃ and holding time 40～60min, the microstructure with mean diameter of grains 70～90μm and liquid fraction 40%～45% can be obtained. However, the microstructure of as-cast billets reheated in semi-solid state was transformed into dendritic-network structure. The analysis of the microstructural evolution mechanism showed that in the early stage of the whole reheating process, the grains grow up fastly mainly through coalescence. The driving force of grains coarsening and spheroidizing is phase interface energy increasing and interfacial tension.

关 键 词：半固态金属 二次加热 A2017合金 组织演化 

分 类 号：TG249.9[金属学及工艺—铸造] TG146.2[一般工业技术—材料科学与工程]