Computer Simulation of High-temperature Deformation Behavior of Austenitic Stainless Steel

A computer simulation system which calculates the high-temperature tensile deformation of austenitic stainless steel has been developed on the basis of a dislocation modeling. Plastic deformation by the external force is expressed by the flow of dislocations, and the load-deformation curves are computed as the reaction of material to a tensile testing machine. The formation of internal stress by work hardening and its recovery is represented by a cell structure model in which the framework is constructed by edge dislocation dipoles. The model also accounts for the temperature dependence of the effective stress by three types of dislocation motion ; free, pinning and dragging. The simulation system outputs computed curves of load-elongation and creep strain-time relation for the conventional tensile and creep tests. By selectiong suitable parameters in the model, the system is designed to allow us to predict the stress-strain and creep-rupture behavior of austenitic stainless steel. The model is so flexible that we can obtain good curve fitting to the experimental data of NRIM Creep Data Sheet.