Microstructural Evolution in Elastic Media

 

Abstract

Many structural metals and ceramics form via a solid state phase transformation, in which a thermodynamically stable single phase separates, upon lowering of temperature, into multiple phases.  The details of the resulting multi-phase microstructure depends on mass diffusion, surface energy and elastic stresses.  In this work, the evolution of precipitate-matrix microstructures in binary alloys is simulated.  Stresses arise from misfit between the phases and from applied loads.  Both sharp interface (boundary integral) and diffuse interface (Cahn-Hilliard) methods are used to track the evolution of the precipitates.  Results show that elastic stresses lead to novel features such as solid-state dendrites, `inverse' coarsening, precipitate alignment and morphological instabilities leading to particle splitting.