Substructure and Texture Evolution in an Annealed Aluminum Alloy at Medium Strains

Abstract

Substructures are widely observed in plastic deformation of aluminum alloys and are of practical significance, but studies on characterization of substructure in a scale much larger than the grain size and how it affects texture evolution are still lacking. In the current study, we performed channel die compression on an annealed AA1100 aluminum sheet along the normal direction (ND) at medium strains at room temperature. The microstructure and texture were characterized by electron backscattered diffraction. Texture evolution was simulated by incorporating octahedral {111}〈011〉 and nonoctahedral {hkl}〈011〉 slip systems in the visco-plastic self-consistent model. The rotation axes and the misorientation angles for the deformation texture variants were calculated. The results show that substructuring proceeded in all the texture components but in a heterogeneous manner. The 〈001〉||ND texture presents high-angle boundaries (HABs) of 15 deg through 30 deg without rotation axis clustering and almost no extra high-angle boundaries (EHABs) of 30 deg through 60 deg; while the HABs and the EHABs coexisted in the 〈011〉||ND and the 〈112〉||ND textures. The rotation axes of the EHABs preferentially clustered at 〈011〉 and 〈111〉. Under plain strain compression, multiple deformation texture variants created by substructuring interwove with each other, resulting in the EHABs with rotation axes clustering. In contrast, the HABs generated by substructuring via dislocation mechanisms showed no rotation axes clustering. Substructuring moderated the texture component intensity and randomized orientations, and resulted in fluctuation of the α-fiber texture and hindered the increase in the rate of the copper texture development.