Point defect concentrations in metastable Fe-C alloys

TL;DR

This study uses density functional theory to predict point defect concentrations in metastable Fe-C alloys, revealing how carbon and vacancies influence defect populations and microstructure formation.

Contribution

It provides the first detailed computational analysis of defect concentrations in metastable Fe-C alloys, linking defect chemistry to microstructural features.

Findings

Carbon interstitials dominate defect species unless vacancies are abundant.

Excess carbon significantly increases vacancy concentration.

Predictions are experimentally verifiable and relevant for steel microstructure understanding.

Abstract

Point defect species and concentrations in metastable Fe-C alloys are determined using density functional theory and a constrained free-energy functional. Carbon interstitials dominate unless iron vacancies are in significant excess, whereas excess carbon causes greatly enhances vacancy concentration. Our predictions are amenable to experimental verification; they provide a baseline for rationalizing complex microstructures known in hardened and tempered steels, and by extension other technological materials created by or subjected to extreme environments.