Geometrical criterion for the activation of prismatic slip in AZ61 Mg alloy sheets deformed at room temperature

Abstract AZ61 Mg alloy was hot-forged and subsequently hot-rolled to a thickness of 1 mm. Tensile anisotropy was investigated at room temperature within the plane of the rolled sheets. When the basal planes were tilted by more than 16.5° towards the tensile axis, basal 〈 a 〉 slip was a dominant deformation mechanism and a small elongation of 8% was obtained. Otherwise, prismatic 〈 a 〉 slip became a dominant deformation mechanism and a large elongation of more than 20% was obtained. The basal-plane tilt angle was considered as a geometrical criterion for the activation of the prismatic 〈 a 〉 slip at room temperature. The corresponding Schmid factor ratio, or equivalently the critical resolved shear stress ratio of prismatic to basal slip, was found to be 1.5–2.0.