Professor Perry Leo

Aerospace Engineering and Mechanics

University of Minnesota

 

Elastic effects in diffusional phase transformations

 

Abstract

 

Many structural metals and ceramics form via diffusional phase transformations, 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 microstructures in both binary bulk alloys and thin films is simulated.  Stresses arise from compositional misfit between the phases, epitaxial misfit and applied loads. Both sharp interface (boundary integral) and diffuse interface (Cahn-Hilliard) methods are used to track the microstructure.  Simulation results show how elastic stresses can influence the microstructural patterns that form during phase transformations.