等温等压热处理对AM50镁合金组织和硬度的影响

针对铸态镁合金性能，研究了等温等压热处理后其显微组织和硬度的变化情况，探讨了显微组织发生改变的原因。实验结果表明，半固态等温热处理后，溶解于基体中的第二相二次析出，成鱼骨状分布于基体表面；随着压力的增大，晶界溶解，二次析出的第二相形状发生变化，出现分离、球化和交联的现象，但球化的效果占明显优势；随着压力的增加，材料的硬度下降。

Effects of isothermal and isobaric heat-treatment on microstructure and hardness of AM50 magnesium alloy

In response to the properties of the casting magnesium, this paper describes the investiga- tion into the effects of isothermal and isobaric heat-treatment on microstructure and hardness of AM50 magnesium alloy and the reason of the microstructure transformation. The experiment results show that, i- sothermal heat treatment allows the secondary precipitation of the second phase dissolving in the matrix to be of bone-like distribution in the matrix surface. The increasing pressure is followed by the dissolution of the grain boundary, which results in change in the second phase separated out from the basal body, giv- ing rise to the separation, the ball and the cross linking, and the ball phenomenon shows distinet advan- tage. The increasing pressure leads to the drop in hardness.