Dependence of Radiation Induced Segregation of Cr on Sink Dimensionality and Morphology in Fe-Cr Alloys

TL;DR

This study uses kinetic Monte Carlo simulations to explore how the shape and dimensionality of sinks like grain boundaries and spherical domains influence chromium segregation in Fe-Cr alloys under radiation, revealing complex dependencies.

Contribution

It introduces a detailed analysis of sink dimensionality effects on radiation-induced segregation using kinetic Monte Carlo and analytical models in Fe-Cr alloys.

Findings

Segregation profiles vary significantly with sink geometry.

Linear dependence on sink density observed for planar sinks.

Complex, non-linear dependence in spherical sink domains.

Abstract

Radiation-induced segregation (RIS) and chemical redistribution in structural alloys can significantly degrade material performance, ultimately leading to failure. In this study, building on previous work by the authors [1], we investigate how the dimensional characteristics of sinks influence solute concentration distributions and segregation behavior. Specifically, we utilize a kinetic Monte Carlo (KMC) model to simulate atomic-scale diffusion and analyze segregation processes in an Fe-3Cr alloy. Our analysis includes three representative sink geometries: one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) planar sinks to capture the effects of sink dimensionality on Cr segregation at grain boundaries (GBs). We also found solutions of concentration and segregation profiles in these cases as well as for a 3D spherical sink. KMC simulations are performed over a range of temperatures to assess thermal effects on Cr redistribution. The results reveal distinct segregation profiles and concentration gradients, although the dependence with sink density seems to remain linear in all cases with planar sinks. The analytical results show that this is not the case in spherical domains, with a more complex dependence of segregation on sink density. Our finite difference solutions for domains including 2D and 3D planer sinks show agreement with corresponding KMC results.