Evaluation of Residual Stresses in a Rolled Sheet of AA 6082-T6 Aluminium Alloy

Abstract

This study aims to determine and evaluate residual stress components and anisotropy degrees in specimens of a rolled sheet of AA 6082-T6 aluminium alloy. The residual displacements were measured, using an optimised micro-indentation method, with an absolute error down to ±200 nm. A distribution of 8 micro-indents allowed to measure the residual displacements in 5 centroids of several geometric figures associated with that distribution. The results reveal that the normal components are compressive and much higher than the tangential components. The principal directions associated with each centroid were very close to the rolling direction. From the graphical tool called Mohr's circle, it was possible to detect a smooth variation associated with the residual stress state in the rolling direction. Finally, both the residual stress states and anisotropy degrees, evaluated along the rolling direction, would respond to a function which would be similar to the planar rotation function corresponding to the normal and tangential components.