通道间隙对等径角轧制AZ31镁合金板材组织与性能的影响

Effect of channel clearances on microstructures and mechanical properties of AZ31 magnesium alloy sheet processed by equal channel angular rolling

研究了不同通道间隙下,AZ31镁合金板材在等径角轧制过程中晶体取向的演化特征以及通道间隙对其显微组织和力学性能的影响。X射线衍射分析表明在等径角轧制过程中,随着通道间隙的减小,晶体取向变化加大,(0002)基面取向减弱。等径角轧制后,孪晶明显增多,且随着通道间隙的减小,孪晶数量逐渐增多。单向拉伸试验表明,等径角轧制后的板材,其变形行为和力学性能存在明显的各向异性特征,与等径角轧制前的板材相比,在轧向其屈服强度明显降低由轧制前的240MPa降至155MPa,抗拉强度略有增加,但随着通道间隙的减小,断裂延伸率略有增大;在横向其屈服强度和抗拉强度均增大,随着通道间隙的减小,屈服强度和抗拉强度略有减小,但断裂延伸率增大。

The evolvement characteristic of crystal orientation of AZ31 magnesium alloy sheet at different channel clearances and effects of channel clearances on its microstructures and mechanical properties during equal channel angular rolling （ECAR） are investigated. By XRD patterns, it is found that the change of crystal orientation increases and （0002） basal plane orientation decreases with channel clearance decreasing during ECAR. After ECAR, twins increase obviously and increase gradually with channel clearance decreasing. By tensile test, it is known that distortion behavior and mechanical properties of the sheet processed by ECAR have obvious anisotropy, and compared with as-received sheet, in rolling direction its yield strength decreases from 240MPa to 155MPa and ultimate tensile strength increases slightly, while the elongation to failure is increased slightly with channel clearance decreasing; but in horizontal direction both its yield strength and ultimate tensile strength increase, and with channel clearance decreasing they decrease slightly but elongation to failure is also increased.