Rapid estimation of the bimaterial interface energy for engineering steels

Various measures of material performance depend on the interface energy between precipitates and a common host matrix. Despite its significant role in macroscopic material performance, interfacial energies are hard to measure experimentally or model with a high degree of precision. The interface energy arises due to crystal lattice mismatch between elastically stiff precipitates and the host matrix, among other factors. The objective of this work is twofold. First, we present an elastic dislocation-based model of the semi-coherent interface energy formed between two elastically dissimilar crystals and compute the corresponding interface energy. We build upon earlier works by treating the dislocation core with a non-singular methodology, which smooths the dislocation core over a finite width, removing the need for ad-hoc dislocation cutoff parameters. Second, we apply our model towards estimating the interface energy for ∼2000 samples of alloy data of varying composition obtained from physical materials databases. Each sample is comprised of up to 12 precipitates, and nine candidate orientation relationships across four unique crystal structures, totalling ∼40000 calculations. To add insight to our results, we present an asymptotic analytical model for the interface energy which rationalises the scaling of interface energy with surface dislocation density. This work demonstrates how a conceptually simple dislocation-based model can provide guidance towards materials selection criteria.