差速循环扩挤制备的AZ31镁合金的组织和力学性能

Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Prepared by Cyclic Expansion-Extrusion with Asymmetrical Extrusion Cavity

摘要:

对AZ31镁合金进行了差速循环扩挤（CEE-AEC），研究了变形道次对晶粒细化、织构演变和力学性能的影响。结果表明，在差速循环扩挤过程中，发生了连续动态再结晶（CDRX）和非连续动态再结晶（DDRX），平均晶粒尺寸从344 μm减小到11.7 μm。随着加工道次的增加，（0001）基面织构强度逐渐增加。差速循环扩挤模具中不对称型腔的存在极大地引起了基面织构的偏转。此外，合金的机械性能得到改善，并且屈服强度（TYS）、抗拉强度（UTS）和断裂伸长率（EL）分别为109 MPa，211 MPa和30.8%。

Abstract:

Cyclic expansion-extrusion with an asymmetrical extrusion cavity (CEE-AEC) was performed on AZ31 magnesium alloy, and the effects of deformation passes on grain refinement, texture evolution, and mechanical properties were studied. The results show that during the CEE-AEC process, the continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) occur, and the average grain size reduces from 344 μm to 11.7 μm. The (0001) basal texture intensity gradually increases with the increase of processing passes. The existence of asymmetric cavities in CEE-AEC dies causes a great deflection of the basal texture. In addition, the mechanical properties of the alloy improve, and the tensile yield strength (TYS), ultimate tensile strength (UTS), and elongation (EL) are 109 MPa, 211 MPa, and 30.8%, respectively.