Grain subdivision and its effect on texture evolution in an aluminum alloy under plane strain compression

Abstract

Grain subdivision is widely observed in plastic deformation of aluminum alloys and of practical significance, but characterization of grain subdivision in a scale much larger than the grain size and how it affects texture evolution is still lacking. In this work, we performed channel die compression on an annealed AA1100 aluminum sheet along the normal direction (ND) at medium strains and room temperature. Micro structure and texture were characterized by electron backscatter diffraction (EBSD). The rotation axis and the misorientation angle for the deformation texture variants were calculated. The results show that grain subdivision proceeded in all the grains but in a heterogeneous manner. The <001>∥ND grains present high angle boundaries (HABs) of 15–30° without rotation axis clustering and almost no extra high angle boundaries (EHABs) of 30–60°; while the HABs and the EHABs coexisted in the <011>∥ND and the <112>∥ND grains. The rotation axes of the EHABs preferentially clustered at <011> and <111>. Under plain strain compression, multiple deformation texture variants created by grain subdivision interweaved with each other inside original grains, resulting in the EHABs with rotation axes clustering. In contrast, the HABs generated by grain subdivision via dislocation mechanism showed no rotation axes clustering. Grain subdivision leveraged in the texture component intensity and randomized orientations, resulted in fluctuation of the α-fiber texture.