Dynamics of self-interstitial cluster migration in pure alpha-Fe and Fe-Cu alloys - art. no. 144102

摘要

We report the results of molecular dynamics simulations of self-interstitial cluster diffusion in pure alpha-Fe and in a dilute Fe-1.0 at. % Cu alloy for a number of cluster sizes, nless than or equal to20. We find that the effect of this oversized substitutional solute is to enhance the three-dimensional character of small-cluster diffusion and to impact the general cluster diffusion properties. We explain this through a mechanism directly based on the interactions between the atomic displacement field of the Cu atoms and the self-interstitial clusters. Based on these results, we derive simple power laws for the extrapolation of migration energies and diffusion prefactors to larger sizes, required for longer-range microstructural evolution models. These laws represent an improvement over current parametrizations used in previous calculations. [References: 35]