研究大规格等温模锻 AZ80-Ag镁合金机匣在不同热处理条件下的组织演变和拉伸力学性能.采用扫描电镜和电子背散射衍射对合金的显微组织进行表征,并测试其在室温、120 和 150℃下的拉伸力学性能.结果表明,室温下强化作用更强的不连续析出相在T5 样品中的面积分数高于T6 样品的面积分数.因此,T5 样品的析出强化作用更强,室温抗拉强度最高.但随着温度的升高,T5样品的抗拉强度迅速下降,在150℃时低于T6样品甚至锻造态样品的抗拉强度.这是由于不连续析出相的抗高温软化能力低于连续析出相的抗高温软化能力.
The microstructure evolution and tensile mechanical properties of the isothermal die forged AZ80-Ag casing with large size under different heat treatment conditions were investigated.The microstructure was characterized by scanning electron microscope and electron backscatter diffraction techniques,and the tensile mechanical properties were tested at room temperature,120 and 150℃,respectively.The results show that the area fraction of discontinuous precipitates with stronger strengthening effect is higher in T5 sample than that in T6 sample,therefore T5 sample exhibits a more pronounced precipitation hardening and the highest tensile strength at room temperature.However,as the temperature increases,the tensile strength of T5 sample decreases rapidly and is lower than that of T6 sample or even the as-forged samples at 150℃.The reason is that discontinuous precipitates are less resistant to high temperature softening than continuous precipitates.