MASKE: A Kinetic Simulator of Coupled Chemical and Mechanical Processes Driving Microstructural Evolution

Abstract

The microstructure of materials evolves through chemical reactions and mechanical stress, often strongly coupled in phenomena such as pressure solution or crystallization pressure. This article presents the Microstructural Simulator of Kinetic Evolution (MASKE), a simulator to address the challenge of modeling coupled chemomechanical processes in microstructures. MASKE represents solid phases as agglomerations of particles whose off-lattice displacements generate mechanical stress through interaction potentials. Particle precipitation and dissolution are sampled using kinetic Monte Carlo, with original reaction rate equations derived from transition state theory and featuring contributions from mechanical interactions. Molecules in the solution around the solid are modeled implicitly through concentrations that change during microstructural evolution and define the saturation indexes for user-defined chemical reactions. The salient features of the software are described first, followed by two examples on a nanocrystal of calcium hydroxide addressing its chemical equilibrium and its mechanical response under a range of imposed strain rates. The predicted processes of stress-driven dissolution and recrystallization induce a complex coupling among solution chemistry, pressure solution, and plastic deformations, which is presented and discussed.