Simulated spatial and temporal dependence of chromium concentration in pure Fe and Fe-14%Cr under high dpa ion irradiation

TL;DR

This study models how chromium ions distribute and evolve in iron alloys under high-dose irradiation, considering factors like damage, temperature, and microstructure, revealing deviations from traditional implantation predictions.

Contribution

It introduces an ab initio informed rate theory model that captures complex spatial and temporal behaviors of implanted ions during irradiation, including segregation and defect interactions.

Findings

Ion profiles differ from SRIM predictions due to radiation-enhanced transport.

Temperature and grain boundaries significantly influence alloy composition distribution.

Segregation effects are critical in understanding irradiation-induced material changes.

Abstract

In this work we develop an ab initio informed rate theory model to track the spatial and temporal evolution of implanted ions (Cr+) in Fe and Fe-14%Cr during high dose irradiation. We focus on the influence of the specimen surface, the depth dependence of ion-induced damage, the damage rate, and the consequences of ion implantation, all of which influence the depth dependence of alloy composition evolving with continued irradiation. We investigate chemical segregation effects in the material by considering the diffusion of the irradiation-induced defects. Moreover, we explore how temperature, grain size, grain boundary sink strength, and defect production bias modify the resulting distribution of alloy composition. Our results show that the implanted ion profile can be quite different than the predicted SRIM implantation profile due to radiation enhanced transport and segregation.