Influence of texture on Hall-Petch relationships in an Mg alloy

The influence of changes in crystallographic texture on the Hall-Petch (H-P) relationship for an Mg alloy was investigated. First, the texture variations were facilitated by changing the uniaxial tensile loading orientation with respect to the normal direction of the rolled Mg plate. With a strong plane texture of the as-received material, the initial dominant deformation mechanisms were systematically varied from the basal slip and prismatic slip to extension twinning, as well as combinations thereof. Second, different grain sizes were produced for each loading orientation through isochronal annealing at various temperatures up to 773 K while closely monitoring grain size and texture distributions. The experimental results are presented for the grain growth kinetics during annealing, changes in yielding behavior as a function of grain size and initial texture, and H-P relationship as a function of the texture. Moreover, the effects of changes in texture and dominant deformation mechanism on H-P parameters - namely, friction stress, sigma(0), and strength coefficient, k(sigma) - are discussed. Finally, H-P relationships for each individual deformation mode including basal, prismatic and pyramidal slips as well as extension twin are identified. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.