文摘

The deformation-induced processes by tensile loading of X5CrNi18-10 austenitic stainless steel in the temperature range of 77 K to 413 K (−196 °C to 140 °C) were investigated. The results were presented in the form of stress–temperature-transformation (STT) and strain–temperature-transformation (DTT) diagrams. The thermodynamic stability of the austenite with respect to the ε- and α′-martensite transformations was reflected in the STT and DTT diagrams. Furthermore, conclusions could be drawn from the transformation diagrams about the kinetics of stress- and strain-induced martensitic transformations. The diagrams laid foundations for the development of a new method of quantitative determination of strength and elongation contributions by means of induced and often overlapping deformation processes in the austenite. In this context, the plastic strains contributed by the glide and shearing of austenite were quantified and presented in connection with the ε and α′ TRansformation-Induced Plasticity effects. Each deformation process was shown to have made a contribution to the strength and ductility, with a magnitude proportional to its dominance. The summation of such contributions provided the tensile strength and the uniform elongation of the steel. In other words, tensile strength and uniform elongation could be derived from a rule of mixtures. The newly proposed method was capable of explaining the anomalous temperature dependence of uniform elongation in the alloy investigated. Manuscript submitted August 4, 2014.