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 MASKE: a simulator to address the challenge of modelling coupled chemo-mechanical 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 solution around the solid are modelled implicitly, through concentrations that change during microstructural evolution and define the saturation indexes for user-defined chemical reactions. The structure and implementation of the software are explained first. Then, two examples on a nanocrystal of calcium hydroxide address its chemical equilibrium and its mechanical response under a range of imposed strain rates, involving stress-driven dissolution and recrystallization. These examples highlight MASKE's distinctive ability to simulate strongly coupled chemo-mechanical processes. MASKE is available, open-source, on GitHub.