Study on γ′-phase Micromorphology Evolution of Nickel-based Superalloy with Monte Carlo Simulations

Nickel-based single-crystal superalloys are widely used in aerospace and energy applications due to their excellent high-temperature strength, creep resistance, and thermal stability. As the effects of temperature on the morphology and structural evolution of γ'-Ni₃Al precipitates in nickel-based superalloys remain unclear, a combined method of cluster expansion and Monte Carlo simulations was adopted in this study to systematically investigate the atomic-scale morphological and structural changes of γ'-Ni₃Al precipitates in the Ni_0.87Al_0.13 single-crystal superalloy model. The results show that at 200 K, the particle morphology of γ' precipitated phase presents a truncated octahedral shape consisting of six100 crystalline surfaces; as the temperature increases to 300 K, the γ' precipitated phase transforms into a lamellar shape, and the interface between the γ' phase and the γ phase is straight and clear; with the further increase of the temperature, the γ' phase starts to dissolve gradually, and the concentration of the Al atoms within the γ' phase begins to decrease subsequently. Finally, at 1100 K, the γ' phase completely dissolves and disappears, forming a Ni_0.87Al_0.13 uniform and disordered solid solution. This work provides a theoretical basis for revealing the evolution rules and internal mechanism microstructures in nickel-based single-crystal superalloys, and offers useful reference for the process optimization andengineering application of the alloys.