Effect of texture on load partitioning in Ti-6Al-4V

Abstract

Neutron diffraction has been used to characterize the evolution of residual elastic strain in grains with different orientations due to room temperature plastic deformation in two plate product forms of Ti–6Al–4V. The evolution of lattice strains has been rationalized using a two-phase elastic–plastic self-consistent model using only the texture difference between the two product forms. It is found that the elastic properties of both the bulk and individual orientations can be reproduced quite satisfactorily, with a C′ modulus of the β phase of 15GPa. The residual microstrains produced are generally greater in the unidirectionally rolled material than the cross-rolled, but are smaller than in Ti-834. The residual strains accumulated in the (0002) orientation are near-zero, which can only be reproduced in the modelling by assuming a critical resolved shear stress for 〈c+a〉 slip only 1.5× that for 〈a〉 slip, compared to the 3× factor found for isolated single crystals. The implications of this for our understanding of deformation in these materials are discussed.