Effect of α texture on the tensile deformation behavior of Ti–6Al–4V alloy produced via electron beam rapid manufacturing

Abstract

In the present work, the characteristics of α texture transformed from the strong <100>β fiber texture and their effect on the tensile deformation behavior of Ti–6Al–4V alloy fabricated using electron beam rapid manufacturing (EBRM) have been investigated. The results show a concentrated distribution of transformed α texture along the transverse direction (TD) while a relatively random distribution along the longitudinal direction (LD). This different orientation distribution of α phase leads to anisotropy in tensile strength. Moreover, inhomogeneous deformation is found in the longitudinal sample, which is not observed in the transverse sample. This can also be attributed to the relatively discrete α orientation distribution in the LD. The relationship between the deformation ability of each columnar prior β grain and its corresponding crystallographic orientation was investigated. Both the calculated and experimental results indicate that a relatively low deformation resistance is found when the angle of the [001]β direction of a columnar grain to the LD is relatively small and a higher deformation resistance is found when the angle is about 45°. During the loading process in the LD, deformation may concentrate in some “weak” columnar grains with relatively low deformation resistance, resulting in decreased integral ductility compared to the transverse sample.