First-principles investigations for clustering behavior of W and Co in nickel-based single-crystal superalloys

In nickel-based single-crystal superalloys, the clustering growth of solute atoms is a potential form that can generate a greater strengthening effect. Herein, first-principles calculations are employed to investigate the clustering behavior of W and Co in γ phase, including the occupancy mechanism, interatomic interactions, and electronic properties. It is reveals that compared to dispersed atoms, W shows a greater propensity for forming W–W clusters. After W–W bond formation, the total energy decreases from −634.247 eV to −649.569 eV. Co prefers to occupy the second-nearest neighbor of W–W, further reducing the system total energy (−651.110 eV). The doping of Co is found to strengthen the W–W interactions. The stabilizing mechanism is attributed to the replacement of the weak Ni–Ni with stronger Ni–W, W–W, and W–Co interactions. This work sheds light on the clustering behavior of doped W and Co, contributing to an understanding of the stabilizing mechanisms of atomic clusters.