Formation of unusual rolling texture in a Mg-Al-Mn alloy sheet by large-strain hot-rolling

We report the formation of unusual texture at the sheet-surface of a rolled Mg-3Al-0.4Mn (mass%) alloy. After large-strain hot-rolling and annealing, typical basal texture with the strong parallel alignment of the (0001) poles to the sheet normal direction (ND) is formed at the center of the sheet. However, at the sheet-surface, unusual texture with the vertical tiling of the (0001) poles from the ND is observed. At the sheet-surface, prismatic slips are facilitated, and dynamic recrystallization occurs extensively by the subdivision of matrix-grain and tension twinning, forming high fraction of fine basal-textured grains, while small fraction of off-basal-textured grains with the unusual texture is also apparent. Static recrystallization occurs preferentially by the growth of the nonbasal-textured grains, leading to the unusual texture development. In contrast, relatively high fraction of deformed grains is preserved at the center, promoting the growth of basal-textured grains and the formation of the typical basal texture.