MS-informed misfit approximation model for the interaction energy between substitutional atoms and screw dislocations in BCC iron-based alloys

Abstract

This study presents a molecular statics (MS)-informed misfit approximation (MA) model for estimating the interaction energies between substitutional atoms and screw dislocations in BCC iron-based alloys. The MA model is transplanted into the BCC system and verified by MS and DFT. Based on the MS-constructed screw-kink structures, the dominate mechanism for solute elements varies with misfit sizes. Specifically, the larger size is relevant with direct interaction between substitutions and kinks, while the indirect movement from inside to outside the screw core is involved for the smaller one. The predicted solute hardening effects are consistent with experimental results, demonstrating the applicability of the MA model to estimate the solute-kink interaction energies in BCC-Fe alloys.