AZ80镁合金半固态等温处理过程中的组织演变

Microstructures evolution of AZ80 magnesium alloy in semi-solid isothermal treatment process

摘要:

本文对挤压态AZ80镁合金进行了不同时间的等温处理，观察分析了半固态微观组织的演变规律与晶内液池的形成过程。结果表明：在等温过程中，组织演变过程主要表现为晶粒合并粗化、晶界局部液相出现和液相区扩大、α-Mg晶粒球化转变、熟化与合并长大几个阶段。挤压AZ80镁合金半固态等温处理过程中α-Mg晶粒内液池出现机制以α-Mg晶内溶质元素富集处发生局部优先熔化为主。

Abstract:

This paper deals with the evolution law of microstructure and formation process of intracrystalline liquid pool of extruded AZ80 magnesium alloy after being treated through semi-solid isothermal treatment (SST) for different time. The result show that, with the semi-solid isothermal process, merger of grain coarsening occurs firstly, and then liquid phase appeares and expansion; with the increase of isothermal holding time, the α-Mg grains separated by liquid phase and tend to spheroid constantly, Ostwald ripening and grain coalescing will become the main mechanism with continue increase holding time. And the liquid pool inside the α-Mg grain is caused with the main mechanism of intracrystalline partial melting priority due to elements enrichment. And the partial zone with low melting cased with the solution elements enrichment melting priority is the main mechanism of intracrystalline liquid pool inside the α-Mg grain.