Effect of Single-Pass Rolling on Microstructure and Mechanical Properties of AZ31 Alloy Processed by Equal Channel Angular Pressing

In this study, AZ31 alloys were subjected to multi-pass equal channel angular pressing (ECAP) and subsequent single-pass rolling (SPR) with increased rolling reductions. The grain structure, texture and mechanical properties of the alloys at different processing states were investigated. Microstructure results showed that, the grain structure and texture of the alloy were greatly changed and varied with the rolling reduction. The grain structure was heterogeneous as partial dynamic recrystallization (DRX) took place at low rolling reduction and turned to be homogeneous as complete DRX occurred at the high rolling reduction. The non-basal texture produced by ECAP was changed by the subsequent SPR into approximate basal type with lower Schmid factors. The tensile results showed that the strength and ductility of the ECAP-rolled alloys was simultaneously improved as the rolling reduction increases. A superior combination of higher strength and good ductility was achieved, which largely reduced the reported strength-ductility imbalance. This improvement was attributed to the grain refinement, strain hardening and texture transformation contributed by the high-reduction rolling.