Understanding the  Superior Mechanical Properties  Of Mg-3al-Zn Alloy Sheets: Role of Multi-Type Unique Textures

Abstract

In this work, Mg–3Al–1Zn (AZ31) alloy sheets were produced by transverse gradient extrusion (TGE) process. The flow behavior and dynamic recrystallization during extrusion were systematically analyzed. The microstructure, texture and mechanical behavior of extruded AZ31 sheet were also investigated and compared with conventional extruded (CE) sheet. The results showed that fined grain structure and multi-type unique textures were formed in the TGE sheet because of the introduction of additional flow velocity along transverse direction (TD) and flow velocity gradient along extrusion direction (ED) during extrusion. The base poles gradually deviated away normal direction (ND) from edge to center of the TGE sheet along TD, and the largest inclination angle at center region reached around 65 ° . Furthermore, the base poles inclined from ED to TD 40-63 ° , in addition to the center region of the TGE sheet. As a result, the TGE sheet showed higher ductility and  n -value, but lower yield strength and  r -value in comparison with the CE sheet. The largest elongation of 41% and the lowest yield strength of 86.5 MPa could be obtained for the ED-center sample in the TGE sheet due to the more basal  slip and tensile twins were easy to be activated during deformation.