Python Module for Predicting Interfacial Geometric Energy (PIG-E): Code Documentation

Author(s):

Heather Murdoch, Benjamin Szajewski, Efrain Hernandez, Matthew Guziewski, and Daniel Magagnosc

Abstract:

A key parameter when modeling precipitation is the interfacial energy between the matrix and precipitate. The interfacial energy comprises two contributions, a chemical component and an elastic strain energy component. Thermodynamic modeling approaches (i.e., CALPHAD) are able to predict the chemical contribution. However, accounting for the elastic strain energy remains a challenge. Here, a Python code is developed to implement a dislocation-based approach for determining the elastic strain energy contribution. The code, which was developed for high-throughput computations, requires crystallographic data, elastic constants, and an interface orientation relationship for the matrix and precipitate. From these inputs, a bimaterial interface is described using a transformation matrix, which transforms the precipitate crystal lattice to the matrix crystal lattice, and candidate Burgers vectors for the interface. The dislocation density of the interface is then minimized, and the corresponding elastic strain energy is determined using a non-singular approximation of the dislocation strain field.