Texture Segregation and Texture Change in the Biaxial Stretching of AA6016

Abstract

Sheets of the Al-Mg-Si alloy AA6016 have been prepared with different microstructures by rolling and annealing, followed by heat treatment to the T4 condition. These have been biaxially stretched using the Marciniak driving blank method, and their limit strains measured. Such biaxial stretching limits are very sensitive to inhomogeneity with length scales greater than about half the sheet thickness, and significant factors in that inhomogeneity are the materials grain size and the spatial segregation of texture. In this material, it appears that colonies of cube textured grains have an effect on the limit strains. However, there is significant change of texture during stretching and this texture evolution also needs to be considered. Finite element modelling has been used to evaluate the effects of grain size, clustering of the initial texture and texture evolution on the biaxial stretching limits.