The microstructure evolution and mechanical anisotropy of extruded Mg-2Zn-0.4Ce-0.4Mn alloy tube during tension in different directions

Abstract

In this study, the microstructure evolution and mechanical anisotropy of the extruded Mg-2Zn-0.4Mn-0.4Ce alloy tube during tensile loading along the extrusion direction (ED), 45° towards extrusion direction (45°ED) and transverse direction (TD) were investigated, respectively. The results showed that the initial extruded alloy tube had an obvious {0001} basal fiber texture with the symmetrical pole position deviating about 20° from the RD to ED, which resulted in mechanical anisotropy of the tensile yield stress (TYS) when tensile loading along the ED, 45°ED and TD. The deformation behavior of the alloy tube consisted of three stages. In the yield process, the deformation was dominated by prismatic<a>slip under tensile loading along the ED, while the deformation was dominated by basal<a>slip, next were prismatic<a>slip and pyramidal<c+a>slip under tensile loading both along the 45°ED and TD. In the initial stage after yielding, some extension twin (ETW) formed when tensile loading along the three direction, and the deformations were still dominated by the previous slip systems. In the later part of the deformation, the activation of prismatic<a>slip and the nucleation and expansion of ETW gradually reached saturation under tensile loading along the ED. The dominated prismatic<a>slip was gradually replaced by pyramidal<c+a>slip, and accompanied with a small content of contraction twin (CTW) and double twin (DTW), thus forming a typical texture of [0001]⊥ED. For the deformation both along the 45°ED and TD, dominated prismatic<a>slip and subdominant pyramidal<c+a>slip gradually became the main deformation mode after the saturation of basal<a>slip and ETW, and a small content of CTW and DTW also formed, thus forming the texture of [0001]∥ED-RD plane.