Constitutive equations for pure titanium at elevated temperatures

Isothermal compression tests were conducted on pure titanium using a Gleeble 1500 thermal simulator under constant strain rates of 0.001, 0.01, 0.1 and 1.0 s(-1) and at deformation temperatures ranging from 673 to 973 K up to a 60% height reduction of the sample. The high temperature deformation behaviour of pure titanium was characterized based on an analysis of the stress-strain curves. A set of constitutive equations for pure titanium were proposed by employing an Arrhenius-type equation. Material constants, A, beta and activation energy Q were found to be functions of strain. The equations revealed the dependence of flow stress on strain, strain rate and temperature. In order to evaluate the accuracy of the deformation constitutive equations, the mean errors of flow stress between the experimental data and predicted results were plotted. The results show that there is a close agreement between the predicted and experimental stress-strain curves. (C) 2008 Elsevier B.V. All rights reserved.