Orientation imaging microscopy of the shear bands formed in Al-5%Mg alloys during cold rolling

Abstract

Work done by Inagaki et al., has shown that the rolling texture of Al-Mg alloys becomes more random as Mg content increases beyond 3%, with obvious reductions in the normal FCC rolling texture components. The annealing textures were also weakened with increasing Mg contents, and this is significant because r for a random texture is 1. The alloy Al-5%Mg gave the most interesting results and so this material was selected for further research. Orientation Imaging Microscopy (OIM) has shown that the orientation{123}〈634〉 is subject to pronounced shear banding, and that the texture of the shear band material is substantially random. Shear bands are initiated at grain boundaries, and it seems, on the evidence found so far, that the neighboring grains must be crystallographically softer than the {123}〈634〉 grain through which the shear band propagates. Grains belonging to the α fiber, particularly {110}〈112〉 do not have shear bands but remain as fairly homogenous volumes devoid of obvious evidence of strain localization. The significance of this observation is discussed in the light of the necessity need for random recrystallization essential for improved drawability.