Creep mechanisms and physical modeling for Ti–6Al–4V

Abstract

Abstract The creep behavior of Ti–6Al–4V is investigated at 500 and 600 °C under constant load. The correlation between the values of activation energy and stress exponents indicates that the primary creep, as well as the steady-state creep, was controlled by dislocation climb in the hexagonal phase. The increase in tertiary creep rate was related to the necking development and to nucleation and coalescence of microvoids. The creep rupture data follows the Monkman–Grant relationship under the explored test conditions. Continuum damage mechanics has been applied to develop a constitutive equation, denominated ν concept, which express the strain–time relation. The physical modeling is based on the Ion et al. and Kachanov–Rabotnov formalism. The approach leads to the definition of an operational parameter set, which characterize the three stages of the normal creep curve. For a preliminary evaluation, the parameter set together with an experimental database allows the interpolation and the calculations of creep strain and lifetime. Good agreement has been shown between creep predictions and experimental data of creep curves to different stresses for short-term tests.