Correlation Between Texture Variation and Transverse Tensile Behavior of Friction-Stir-Processed AZ31 Mg Alloy

Abstract

The microstructure and especially the texture of a friction-stir-processed AZ31 Mg alloy were comprehensively characterized by the electron backscatter diffraction (EBSD) technique. Local texture changed significantly from the base material (BM) to the stir zone (SZ) center. The SZ center exhibited strong basal texture with the $\left\langle {0001} \right\rangle$ direction parallel to the processing direction (PD), while the $\left\langle {0001} \right\rangle$ direction from the center to the periphery of the SZ tended to tilt from the PD to the tangential direction (TD). The transverse tensile properties of the processed alloy were reduced compared to the BM due to the inhomogeneous plastic deformation through the specimen length. Necking occurred at the SZ side, and the SZ center suffered the least deformation. A large number of {10-12} extension twins were observed in the SZ side of the deformed specimen, while only a few were in the SZ center. Schmid factor (SF) analyses indicated that most grains in the SZ side were in favorable orientations for extension twinning and basal slip. This might be the main reason why necking and fracture occurred in the SZ side of the friction-stir-processed Mg alloy.