Plastic anisotropy in Titanium 130 and Titanium 318

Abstract

Commercial-purity titanium and Ti-6Al-4 V have been rolled and annealed to produce a wide range of anisotropic conditions. The two extreme conditions correspond with basal-plane poles parallel to the sheet normal and the transverse direction respectively. Control of texture was effected by variations in the rolling temperature and by the introduction of cross rolling. Mechanical behaviour of the sheets was assessed by tensile tests and by plane-strain compression tests. Predictions of the plane-strain strength from tensile strengths and plastic strain ratio values using Hill's theory were made. In some instances, large discrepancies occurred between the predicted and observed plane-strain strengths – these were explained in terms of the deformation mechanisms operative in the constrained and unconstrained tests.