The objective of the present paper is to simulate the superplastic stress–strain behavior by taking into con- sideration of a change in the true plastic strain rate during deformation carried out at a constant nominal strain rate for obtaining various deformation parame- ters as a function of the true plastic strain rate (in other words, as a function of the true plastic strain). Here the flow stress s is supposed to consist of two components, thermal s* and athermal sm so that [7]