Deformation mechanisms and mechanical properties of rolled AZ31 alloy subjected to precompression and subsequent annealing: Effect of annealing temperature

Abstract

This study investigates the effect of annealing temperature on the microstructure, deformation behavior, and mechanical properties of a rolled AZ31 alloy having {10–12} twins. To this end, rolled AZ31 samples are precompressed to 6.0% along the rolling direction (RD) to introduce {10–12} twins and then are annealed at 200, 250, and 300 °C for 1 h. The results reveal that as the annealing temperature increases, the grain size of the annealed samples increases and their RD-oriented basal texture is strengthened. In addition, the number of {10–12} twin boundaries gradually decreases and they almost disappear after annealing at 300 °C. Under tension along the RD, the predominant deformation mechanism of the annealed samples changes from detwinning of preexisting twins to {10–12} twinning as the annealing temperature increases. The annealed samples exhibit different tensile strengths and elongations according to the annealing temperature. Particularly, the tensile elongation increases by 56%, from 13.2% to 20.6%, as the annealing temperature increases from 200 to 300 °C. The variations in the mechanical properties of the annealed samples with the annealing temperature are discussed in detail on the basis of their microstructural characteristics and deformation behaviors.