Microstructure Characterization and FE — Modeling of Plastic Flow in a Duplex Steel

Abstract

To calculate the plastic flow properties of two-phase materials, a large number of micromechanical models based on continuum mechanics principles has been established throughout the past years. Self consistent methods [1–3], rules of mixture (ROM) [4–9], non-linear generalizations of the classical Hashin-Shtrikman bounds [10–12] and the finite-element (FE) method [6, 13–19] have been used for this purpose. All these approaches aim to predict the properties of two-phase materials from the given properties of their constituent phases. Quantitative information from the microstructure, however, is incorporated seldomly in the models, with the exception of those with specific reference to matrix-inclusion-type microstructures. Up to now, only little attention was paid to microstructures different from these special types due to the lack of stereological parameters to characterize general two-phase microstructures quantitatively, and so even finite element based micromechanical modeling methods have been restricted to more or less special two-phase microstructures [21]. It is the aim of this report to present a micromechanical model applicable to general two-phase microstructures. In this course, a stereological parameter is introduced, which fully quantifies the geometrical continuity (GC) of the constituent phases. GC is a quantity of eminent importance, when dealing with various physical properties of coarse grained two-phase alloys possessing interpenetrating phases [20].