The effects of yttrium on the 10-12 twinning behaviour in magnesium alloys: a molecular dynamics study

YC Dou and H Luo and J Zhang, PHILOSOPHICAL MAGAZINE LETTERS, 100, 224-234 (2020).

DOI: 10.1080/09500839.2020.1742939

10-12 twinning is one of the most important deformation modes in magnesium alloys. It is supposed that with high density of 10-12 twin boundaries, magnesium alloys might show exceptional mechanical properties. In this work, the effects of randomly distributed yttrium (Y) on the 10-12 twinning behaviour in magnesium alloys are investigated. Addition of Y makes it easier to activate 10-11 < 11-23 > dislocations and 10-12 twins, compared with pure Mg. Two types (type I and type II) of bi-crystal were constructed to investigate the Y effects on the migration of 10-12 twin boundaries. For the type I bi- crystals, the tensile stress is parallel to the 0001 lattice vector of the matrix. In this case, Y atoms facilitate the migration of 10-12 twin boundary. For the type II bi-crystals, the tension direction is set as the bisector of the angle between -1011 and 10-10 lattice vector of the matrix. In this case, owing to the activation of basal slip, 10-12 twin could be consumed by sequential basal stacking faults. In other words, the effect of Y on the migration of 10-12 twin boundaries depends on the loading direction.

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