目的 研究 AZ91 D 镁合金表面经机械研磨处理的晶粒细化行为与机制。 方法 通过表面机械研磨处理方法对密排六方结构的 AZ91 D 镁合金进行表面强变形处理,并对表面变形层的微观结构进行表征。 结果 经过 60 min 的机械研磨处理后,样品表层形成了厚约 80 μm 的变形层,变形层组织呈梯度分布。 随着距表面距离的增加, 晶粒逐渐变大, 表层晶粒尺寸达到 20 nm。 结论 通过机械研磨处理,AZ91 D 镁合金表面晶粒可以得到明显细化,达到纳米级,晶粒细化机制是孪生和位错滑移的综合作用。

Objective To study the grain refinement behavior and mechanism of AZ91D magnesium alloys after surface mechanical attrition treatment. Methods The AZ91D magnesium alloy in hexagonal-closet-packet structure was treated by surface mechanical attrition treatment ( SMAT) . And the microstructure of surface deformed layer was characterized. Results After 60 min of SMAT, the depth of deformed surface layer was about 80 μm, the structure of which showed a gradient distribution, and the grains became larger with increasing distance from surface, and the surface grain size reached about 20 nm. Conclusion The grain of AZ91D magnesium alloys was obviously refined by surface mechanical attrition treatment; the grain refinement mechanism of AZ91D magnesium alloy by surface mechanical attrition treatment was the results of twinning and dislocation slip.