Temperature dependent constitutive plastic flow behaviour of titanium alloy Ti6Al4V

Abstract The constitutive relationship between stress and strain for titanium alloy Ti6Al4V has been investigated using tensile tests at four different temperatures that is room temperature, 200 °C, 400 °C, and 550 °C. Detail observations on the variation of nature of flow curves in the work hardening regime have been reported at different test temperatures. At room temperature and 550 °C, the flow curves are found to be linear in nature and follow the Hollomon relationship. The flow curves at 200 and 400 °C exhibit non-linear nature and demonstrate Ludwigson relationship. The various constant parameters of above relationships influence the overall strength and ductility of the alloy at different temperatures. The alloy shows presence of premature plastic instability or inflection points in the early period of flow curves and displays a fast decrease in work hardening rate at room temperature and 550 °C, which in turn results in lower values of strain to fracture.