基于镁合金{1012}孪生的织构调整及屈服行为演变

Evolution of texture and yielding behavior induced by{1012} twinning of magnesium alloy

研究挤压态镁合金沿挤压方向预压缩对随后沿ED方向拉伸以及垂直于ED方向压缩屈服行为的影响。结果表明：在所研究的1%～9%压缩预变形范围内，不同预变形量对随后沿ED方向拉伸的屈服影响几乎一样，都能使沿挤压方向拉伸屈服强度下降到约120 MPa，这几乎与沿挤压方向压缩屈服强度122 MPa一致；沿ED方向预压缩将导致垂直于ED方向压缩屈服强度显著增加，且不同预变形量对随后沿垂直于ED方向压缩的屈服行为影响几乎一致。造成不同施载方向屈服行为不一样的原因是不同施载方向孪生变体的最大施密特因子值不同。最大施密特因子值越大，孪生启动时的临界剪切应力越小，屈服强度也就越低。

The effects of compressive pre-deformation on subsequent tension along extrusion direction （ED） and compression perpendicular to ED were investigated in an extruded AZ31 Mg alloy. The results show that the subsequent tensile yield stress decreases to about 120 MPa irrespective of the prestrain from 1%to 9%. The tensile yield stresses of about 120 MPa for the samples subjected to pre-compression are nearly equal to that of compression along ED （about 122 MPa） for the sample without any prestrain. However, the pre-compression along ED leads to an obvious increase in the yield stress for subsequent compression perpendicular to ED. Different prestrains exhibit similar effects on the yielding behavior during subsequent compression perpendicular to ED. Because of the difference in the highest Schmid factors for{10 1 2} twinning, the samples exhibit different yielding behaviors under different strain paths. The critical resolved shear stress （CRSS） decreases with the increase of the highest Schmid factor for {10 1 2} twinning.