Binding of HenV clusters to α-Fe grain boundaries

Abstract

The objective of this research is to explore the formation/binding energetics and length scales associated with the interaction between HenV clusters and grain boundaries in bcc α-Fe. In this work, we calculated formation/binding energies for 1–8 He atoms in a monovacancy at all potential grain boundary (GB) sites within 15 Å of the ten grain boundaries selected (122106 simulations total). The present results provide detailed information about the interaction energies and length scales of 1–8 He atoms with grain boundaries for the structures examined. A number of interesting new findings emerge from the present study. First, the Σ3(112) “twin” GB has significantly lower binding energies for all HenV clusters than all other boundaries in this study. For all grain boundary sites, the effect of the local environment surrounding each site on the HenV formation and binding energies decreases with an increasing number of He atoms in the HenV cluster. Based on the calculated dataset, we formulated a model to capture the evolution of the formation and binding energy of HenV clusters as a function of distance from the GB center, utilizing only constants related to the maximum binding energy and the length scale.