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

초록

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 degrees 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 degrees 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 degrees 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.

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