Unified constitutive modeling of three alloys under a wide range of temperature

Abstract Use of proper constitutive models is essential in evaluating structural integrity of various components using inelastic analysis. In particular, temperature-dependency of the deformation behaviour has a large influence on the result and needs to be taken into account in an appropriate manner. In consideration of the application to analysis of severe accidents, three kinds of materials used in nuclear reactor vessels and their attachments were chosen to study their deformation behaviour under a wide range of temperature from room temperature to 1100 °C and various strain rates, in order to model them in a unified way. Two kinds of temperature dependency corresponding to short range and long range obstacles to dislocation motion were introduced to the models, in order to describe the temperature and strain-rate dependent behaviour in low-temperature and high-temperature regimes connected by the intermediate regime where the temperature and strain-rate dependency was negligible. Systematic process was developed for optimizing the functions and constants included in the models. Reasonable agreements between the model predictions and the experimental data have been obtained for all the alloys studied.