Effect of segregated Al on 10(1)over-bar2 and 10(1)over-bar1 twinning in Mg

N Miyazawa and T Yoshida and M Yuasa and Y Chino and M Mabuchi, JOURNAL OF MATERIALS RESEARCH, 30, 3629-3641 (2015).

DOI: 10.1557/jmr.2015.330

Molecular dynamics simulations of compression deformation of 11 (2) over bar0-textured 2-dimensional polycrystalline pure Mg, Mg-0.1 at.% Al, and Mg-1.0 at.% Al models were performed at 5 and 300 K. A 10 (1) over bar1 twin nucleated before formation of a 10 (1) over bar2 twin in the simulations at 5 K, while a 10 (1) over bar1 twin nucleated after formation of a 10 (1) over bar2 twin in the simulations at 300 K. The formation of a 10 (1) over bar1 twin was the result of the glide of pyramidal < c + a > partial dislocations of 1/610 (1) over bar1 (2) over bar 023. 10 (1) over bar1 twin formation was suppressed at the sites around the Al atoms because the strong Mg-Al bond suppresses atomic shuffling. However, formation was not suppressed at the sites away from the Al atoms because the effect of strong Mg-Al bond is short range. On the other hand, because 10 (1) over bar2 twinning requires the simultaneous glide of zonal dislocations, Al inevitably suppressed 10 (1) over bar2 twinning.

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