Through-Thickness Characterization of Microstructure and Texture in High Purity Aluminum Processed to High Strain by Accumulative Roll-Bonding

Abstract

The deformation microstructure and texture have been characterized by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) through the thickness of high purity (99.99% purity) aluminum sheets processed by accumulative roll-bonding (ARB) up to a total strain of 4.8. This processing route creates a complex strain path, resulting in a characteristic texture changes through the thickness of the sample, very different from that obtained by conventional rolling, and also in a randomization of the overall deformation texture. The microstructure is composed of an equiaxed structure with a high concentration of high-angle boundaries and a small fraction of a lamellar structure with a high concentration of low-angle boundaries. The observations showed a coupling between the local texture and microstructure; the equiaxed regions are composed of deformation texture components and random texture components while the lamellar regions are composed of the deformation texture components, i.e. rolling or shear texture components.