表面机械研磨对AZ31镁合金显微组织和性能的影响

Effect of Surface Mechanical Attrition on Microstructure and Properties of AZ31 Mg Alloy

采用机械研磨法对挤压态AZ31镁合金进行表面纳米化处理,通过显微组织观察、硬度测试、拉伸性能测试研究了表面机械研磨时间对AZ31镁合金组织和性能的影响。结果表明:经3、6、9 min表面机械研磨处理的AZ31镁合金,从表面到芯部形成了不同厚度的变形层,并有大量孪晶产生。随着表面研磨时间的增加,变形层厚度和孪晶体积分数逐渐增加,AZ31镁合金的强度和硬度逐渐增加,伸长率逐渐降低。与原试样相比,6 min表面机械研磨处理的AZ31镁合金抗拉强度和屈服强度分别提高42.6%和110.2%,表面硬度提高35.4%。表面机械研磨时间超过6 min后,合金强度、硬度和伸长率的变化幅度很小。

The surface nanocrystallization of extruded AZ31 magnesium alloy was investigated by surface mechanical attrition treatment(SMAT).The effects of surface mechanical grinding time on the microstructure and properties of AZ31 magnesium alloy were studied by microstructure observation,hardness test and tensile property test.The results show that AZ31 magnesium alloy generates deformed layers with different thickness from surface to core,and a large number of twins are produced after surface mechanical attrition treatment for 3,6 and 9 min.With the increase of surface mechanical attrition time,the thickness of deformation layer and the twin crystal integral number increase gradually,and the strength and hardness of AZ31 magnesium alloy increase gradually,and the elongation decreases gradually.Compared with the original sample,the tensile strength and yield strength of AZ31 magnesium alloy treated by 6 min surface mechanical attrition increase by 42.6%and 110.2%,respectively,and the hardness of the surface increases by 35.4%.The strength,hardness and elongation of the alloy change little when the surface mechanical grinding time exceeds 6 min.