A typical two phase microstructure consists of a topologically continuous `matrix' phase in which islands of `precipitate' phase are embedded. Usually, the matrix phase is also the majority phase in terms of volume fraction. However, sometimes this relationship between the volume fraction and topology is reversed, and this reversal is known as phase inversion. Such a phase inversion can be driven by an elastic moduli mismatch in two-phase solid systems. In this paper (submitted to Philosophical magazine), we show phase inversion, and the effect of the elastic moduli mismatch and elastic anisotropy on such inversion.

Abstract:

We have used phase field simulations to study elastic stress driven phase inversion in which an initial microstructure with a minority phase embedded in a majority phase evolves to one in which the latter becomes embedded in the former. Such phase inversion is possible if the majority phase is elastically stiffer than the minority phase. For a given set of parameters (volume fraction and elastic moduli of the phases), phase inversion occurs at a characteristic microstructural length scale ($\ell^{c}$). Our results show that $\ell^{c}$ is lower for systems with larger mismatch in elastic moduli, and (to a smaller extent) in those with greater elastic anisotropy.