Anisotropic compressive behavior of extruded Mg alloy plates with different width–thickness ratios

Investigation of the microstructural characteristics and compressive properties of extruded AZ31 alloy plates with width–thickness ratios (w/t ratios) of 1, 2, and 3 revealed that a higher ratio promotes dynamic recrystallization (DRX) behavior during hot extrusion. This leads to a decrease in both the fraction of non-DRXed grains and the average grain size. Extruded alloy with a w/t ratio of 1 exhibits a ring basal fiber texture that is homogeneously distributed over its entire cross-sectional area, resulting in identical stress–strain behavior under compression along the normal direction (ND) and transverse direction (TD). In contrast, significant anisotropy appears between the compressive behavior along the ND and TD in alloys with w/t ratios of 2 and 3, which is attributed to a difference in the active dominant deformation mechanism (i.e., slip for the ND and twinning for the TD) caused by the strong ND-oriented basal texture. Consequently, the compressive yield strength is up to ~2.25 times higher along the ND than along the TD.