The role of anisotropy in the response of the titanium alloy Ti–6Al–4V to shock loading

Abstract

Manganin stress gauges in lateral orientation have been used to monitor the shock response of Ti–6Al–4V when loaded either parallel to or radial to the long axis of the original bar stock studied in this investigation. Materials characterization has shown that the c-axis of the hexagonal unit cell is preferentially orientated radially to the axis of the bar. Shear strengths measured along the long axis of the bar were found to be in agreement with previous data in the literature, while strength in the radial direction was found to be significantly lower. It was also noted that the lateral stress, when measured in the radial direction, displayed a pronounced drop in the lateral stress after reaching the peak shock stress unlike the longitudinal orientation. This decrease is indicative of an increase in shear strength behind the shock front. In both instances, it is postulated that extensive deformation twinning during the early stages of deformation in the shock and thereafter c+a slip and dislocation tangling builds up over a longer time period, resulting in the higher degree of hardening noted.