Modelling the diffusion of self-interstitial atom clusters in Fe-Cr alloys

• Published in: Philosophical magazine (Abingdon, England) Vol. 88; no. 1; pp. 21 - 29
• Main Authors: Terentyev, D., Malerba, L., Barashev, A. V.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.01.2008; Taylor and Francis; Taylor & Francis
• Subjects: Condensed matter: structure, mechanical and thermal properties; Diffusion in solids; Exact sciences and technology; Physics; Self-diffusion in metals, semimetals, and alloys; Transport properties of condensed matter (nonelectronic); Digital simulation; Molecular dynamics method; Theoretical study; Iron alloys; Chromium alloys; Binary alloys; Quantity ratio; Binding energy; Interstitial impurities; Modelling; Interstitial cluster; Diffusion; Crowdions; Atomic clusters; Self-diffusion; Physical Sciences
• ISSN: 1478-6435; 1478-6443; 1478-6433
• DOI: 10.1080/14786430701727513

The results of molecular dynamics simulations of the diffusion of self-interstitial atom clusters in Fe-Cr alloys of different Cr content are presented. It is shown that, with increasing Cr concentration, the cluster diffusivity first decreases and then increases, in accordance with the predictions of a model developed recently and based on molecular static calculations. The minimum diffusivity is found at about 10 at% Cr for small clusters and it shifts towards lower concentration with increasing cluster size. The migration energy of SIA clusters is found to lie in between the binding energy of a Cr atom with a crowdion and half of it. This indicates that the mechanism of cluster migration is via the movement of individual crowdions from one Cr atom to another. The values obtained statically are much higher and are argued to be more reliable due to better sampling of different configurations in a bigger simulation box.