From microphase properties to macroscopic flow curve: A nanoindentation study on structural steel

Abstract

Since the mechanical performance of a multi-phase steel can be controlled by the volume fraction of its micro-phases, the mechanical properties of each phase might be an important information for developing an advanced structural steel. From this viewpoint, we performed nanoindentation experiments on each phase in a dual-phase steel (consisting of ferrite and bainite phase) with spherical indenters having different radii (550nm, 3.3 m). By theoretical analysis of the nanoindentation data, the true stress-true strain curve of each phase was extracted. With the phase properties, we attempted to predict the macroscopic flow curve of the dual-phase steel. The results are discussed in terms of indentation size effects and the applicability of `rule-of-mixture.`