半固态等温处理与电磁感应加热AZ80-0.2Y镁合金组织的演变

Microstructure evolution of AZ80-0.2Y magnesium alloy processed by semi-solid isothermal and induction heat-treatment

分别使用等温处理与电磁感应加热制备AZ80-0.2Y镁合金半固态坯料,对比等温处理与不同感应加热功率条件下半固态组织形貌特征。结果表明:等温处理半固态组织液相以晶界网状液池为主、固相球内的球形液池为辅;感应加热形成的液相主要由晶内长条状液池为主、晶界网状液池为辅。感应加热制备的半固态坯料比等温处理的半固态组织晶粒更细小,液相率更高;大功率感应加热相对于小功率感应加热,晶粒尺寸小,液相率更高;从室温使用功率4 kW感应加热至590℃用时90 s,平均晶粒尺寸65.1μm,液相率45%,晶粒形状系数2.15,已具备较优的成形性能。

Semi-solid billets of AZ80-0.2Y magnesium alloy were fabricated by isothermal and induction heat-treatment. The differences of microstructure morphologies were compared between isothermal and induction heat-treatment with different heating powers. The results show that the liquid phase mainly exists at grain boundary with isothermal heat-treatment. However, the liquid phase mostly presents intragranular strip shape with induction heat-treatment. The grain size of the billets processed by induction heat-treatment is smaller and the liquid fraction is bigger than that of isothermal heat-treatment. Besides, the semi-solid billets processed by induction heating treatment with bigger power（4 kW） have smaller grain size and more liquid phase. Good formability can be achieved by induction heating with power 4 kW. The average grain size is 65.1 μm, while the liquid fraction is 45%, and grain shape factor is 2.15.