An Electron-Backscattered Diffraction Study of the Texture Evolution in a Coarse-Grained AZ31 Magnesium Alloy Deformed in Tension at Elevated Temperatures

摘要

Electron-backscattered diffraction (EBSD) has been used to investigate the texture evolution during tensile deformation at temperatures between 673 and 773 K of a coarse-grained commercial AZ31 magnesium alloy. A weak (0001) fiber texture was initially present in the hot-rolled magnesium alloy plate. The [0001] directions of the grains spread 0 to 45 deg around the normal direction (ND) of the magnesium alloy plate. This pre-existing weak texture evolved during tensile deformation into a strong texture close to the {0001} <1100>. The [0001] directions of the grains rotated toward the orientations perpendicular to the tension axis of the samples, indicating that the {0001} <1120> slip system appeared to be the most active slip system, especially in the early stages of deformation. The EBSD Schmid-factor analysis revealed that, however, with an increase in strain and the rotation of the (0001) slip plane, the {1122} <1123> slip system appeared to be more favorable. The {1 TOO} <1120> and {1101} <1120> slip systems remained favored throughout the strains investigated, indicating that {1100} and {1101} are two important slip planes for cross slip using the <1120> slip vector. It is found that the misorientation across one coarse grain (as high as 38.2 deg) is accommodated by low-angle grain boundaries (LAGBs). The formation of these LAGBs may be an intermediate stage of the coarse grain refinement that occurred during deformation.