Impact of correlative defects induced by double Re-addition on the ideal shear strength of γ′-Ni3Al phases

Abstract The site preference of Re in γ′-Ni 3 Al phases and the impact of Re-additions on the ideal shear strength σ max of γ′-Ni 3 Al phases are investigated by the first-principles calculation. A correlative energy function Δ E Re A + Re B ( d ) has been adopted to evaluate the interaction between point defects caused by Re-additions, i.e. , Re A and Re B . The results show either attraction or repulsion don’t change the site preference of Re at Al sites, and Re atoms tend to stay away from each other in the double Re-addition system. The σ max in Re A + Re B complexes is not only a function of distances d between Re A and Re B defects, but also depends on the direction [ θ , ϕ ] from Re A to Re B defects. The double Re-addition at preferential Al-Al sites may further elevate the σ max in single Re-addition systems, but an extra substitution of Re for Ni atoms, especially the clustering of Re atoms, is harmful to the strengthening of γ′-Ni 3 Al phase. A careful analysis of Δ E Re A + Re B ( d ) reveals the improvement of σ max of γ′-Ni 3 Al phases induced by Re-addition can be attributed to a week repulsive interaction between Re Al and Re Al defects, and a strong attractive interaction caused by Re-clustering should be responsible for the detrimental effect of excess Re-additions to some extent.