High-Precision Residual Stress Measurement and Correlation with Cross-Sectional Texture in Extruded 6000-Series Aluminium Alloys

Abstract

The extruded profiles of 6000-series aluminium alloys have a textured surface structure, different from those having the inner cube and Goss and surface (110) orientations. This structure difference possibly contributes to the decrease in mechanical properties. Although the mechanism of degradation has been discussed for the size, morphology, and density of precipitates, texture and share band, it is necessary to reconsider it from the viewpoint of residual stress distribution. In this study, we first determine the optimal method to evaluate the residual stress in a textured structure of extruded aluminium profiles. The cosα method with 3-axis oscillation successfully yielded highly precise residual stress values even in extruded aluminium alloys. The regions of preferred orientation corresponded well with the major changes in residual stress as a function of depth from the surface. The boundary of the (110) and (100) textures matched well to the first local maximum in the von Mises stress for both alloys. The grain-growth region of A6005C corresponded to the region between the first and second local maxima of von Mises stress.