Finite-Temperature Atomistic and Continuum Stress Fields of Coherent Precipitates with a Small Lattice Misfit

TL;DR

This paper compares atomistic simulations and continuum elasticity models to accurately describe the finite-temperature stress fields of coherent precipitates in BCC Fe-Cr, highlighting the importance of elastic effects in microstructural evolution.

Contribution

It demonstrates that continuum elasticity models can reliably reproduce atomistic stress fields for small lattice misfit coherent precipitates in BCC Fe-Cr.

Findings

Good agreement in stress-field magnitude and topology between models

Elastic effects significantly influence the Gibbs-Thompson effect

Potential issues with continuum models for larger misfits

Abstract

An accurate description of elastic effects of coherent microstructures is necessary for the predictive modeling of microstructural evolution in many structural materials. To date, there has not been a demonstration on how continuum elasticity models are able to reproduce finite-temperature stress-fields and elastic energy estimates of coherent precipitates from atomistic simulations. We present a comparison of stress-fields of coherent precipitates in the body-centered cubic (BCC) Fe-Cr system obtained from atomistic simulation data and from continuum elasticity modeling. The magnitude and topology of the stress-fields show good agreement between the two approaches, and we show the importance of elastic effects on the Gibbs-Thompson effect for this small lattice misfit system. We conclude with a discussion of potential complications of continuum modeling for systems with larger misfit.