Effects of dislocation-twin interactions on twin evolution and dislocation transformation in AZ31 magnesium alloy

The interaction between dislocations and deformation twins strongly influences microstructural evolution and deformation behavior in Mg alloys. In this work, the effects of dislocation-twin interactions on twinning and slip behavior in AZ31 magnesium (Mg) alloy were investigated using a two-step quasi-in-situ compression approach. The results show that during the initial deformation stage, basal-prismatic/prismatic-basal (BP/PB) interfaces generated by dislocation-twin interactions suppress twin growth while promoting new twin nucleation and non-basal dislocation transformation, with the strongest pinning effect occurring at an intermediate interface density. During subsequent deformation, twin growth continues, while dislocation slip gradually becomes the predominant deformation mode. Basal ⟨ a ⟩ dislocations transform into non-basal dislocation types through distinct pathways governed by geometric compatibility. Direct transformation is favored at high geometric compatibility factor ( m ′), whereas indirect transformation predominates at low m ′ values. These findings reveal how BP/PB interfaces influence twin evolution and dislocation transformation in Mg alloys.