The effect of strain path changes on texture evolution and deformation behavior of Ti6Al4V subjected to accumulative angular drawing

Abstract

The Ti–6Al–4V alloy wires were plastically deformed using the accumulative angular drawing (AAD) process at room temperature with a maximal logarithmic strain ε ~ 0.51. Microstructure and microtexture evolution and inhomogeneity of the Ti alloy wires were investigated quantitatively using the electron backscattered diffraction technique within the scanning electron microscope and compared to wires after conventional linear drawing. Moderate grain refinement was observed after deformation. The kernel average misorientation parameter increased significantly, pointing to evolution of subgrain structure. The yield stress and ultimate tensile strength increased after the AAD and linear drawing and decrease in hardness was observed after the first pass of the AAD and linear drawing process. However, the AAD introduced inhomogeneity in hardness values at the sample cross section. Hardness variation correlates with a local texture asymmetry parameter, while no correlation between hardness and grain size was observed. A Schmid factor analysis indicated that the AAD is inhomogeneously introducing grain orientations that are favorable for prismatic and pyramidal dislocation slip, having a positive effect on the plasticity of Ti–6Al–4V alloy wire during drawing.