Dislocation interaction with C in alpha-Fe: a comparison between atomic simulations and elasticity theory

TL;DR

This study compares atomic-scale simulations and elasticity theory to understand how carbon atoms interact with dislocations in alpha-iron, highlighting the importance of anisotropic elasticity and interstitial distortions for accurate predictions.

Contribution

It demonstrates that combining atomic simulations with anisotropic elasticity theory yields accurate predictions of C-dislocation interactions in alpha-Fe, emphasizing the role of interstitial distortions.

Findings

Quantitative agreement between atomic simulations and elasticity theory when anisotropic elasticity is used.

Isotropic elasticity predicts main interaction trends but misses details.

Considering both dilatation and tetragonal distortion improves interaction accuracy.

Abstract

The interaction of C atoms with a screw and an edge dislocation is modelled at an atomic scale using an empirical Fe-C interatomic potential based on the Embedded Atom Method (EAM) and molecular statics simulations. Results of atomic simulations are compared with predictions of elasticity theory. It is shown that a quantitative agreement can be obtained between both modelling techniques as long as anisotropic elastic calculations are performed and both the dilatation and the tetragonal distortion induced by the C interstitial are considered. Using isotropic elasticity allows to predict the main trends of the interaction and considering only the interstitial dilatation will lead to a wrong interaction.