Kawin: An open source Kampmann–Wagner Numerical (KWN) phase precipitation and coarsening model

Abstract

Kawin, a new open-source implementation of the Kampmann–Wagner Numerical model of precipitation (concomitant nucleation, growth, and coarsening), is presented. An overview of the organization and capabilities of the program is provided, along with an outline of the constituent physics. Kawin is shown to be able to reproduce the results of state-of-the-art commercial software and experimental data for a variety of alloy systems under multiple precipitation conditions. Kawin is capable of simulating the bulk precipitation behavior of multiphase, multicomponent systems in response to complex heat treatments, and contains numerous innovative features to enhance model stability, improve flexibility and usability, and minimize computational expense. Kawin also incorporates sophisticated elastic energy calculations, traditionally ignored in this type of simulation but shown here to significantly impact the precipitation behavior of some systems. The inclusion of native strain calculations enables Kawin to predict the influence of internal or external stress fields on precipitation, as well as track the evolution of precipitate geometry throughout the course of a heat treatment. It is the hope of these authors that this software will facilitate the advancement of precipitation modeling as a tool for materials design.