Anisotropy of low temperature superplasticity of fine grained magnesium alloy AZ31 processed by multidirectional forging

Abstract

Effect of texture anisotropy of Mg alloy AZ31, processed by multidirectional forging, on low temperature superplasticity was studied in tension at 423 and 473 K. Multidirectional forging was carried out up to large cumulative strain of 4·8 with changing loading direction from pass to pass under decreasing temperature conditions. When the basal plane in initial texture is inclined at ∼45° against tensile direction, rotation of basal plane towards tensile direction takes place accompanying with basal slip and grain coarsening or refinement, leading to the highest elongation to failure of 320%. This suggests that superplastic deformation can be controlled by grain boundary sliding accompanied with grain size changes taking place due to continuous dynamic recrystallisation.