Precipitation Behavior of Spherical γ′ Phase in Eutectic Area of Ni 3 Al‐Based Alloy

Understanding and mastering initial status in eutectic area (γ′–γ) of Ni 3 Al‐based alloy under solution treatment conditions are beneficial to its aging treatment and applications. In this work, optimal solution treatment process parameters of JG4246A Ni 3 Al‐based alloy are investigated based on microstructure observation, chemical composition analysis, and micro‐hardness test. Results show that the alloy with solution temperature of 1270 °C for 6 h possess smoother eutectic area (γ′–γ) boundaries, more stable carbides, and relatively higher micro‐hardness. More importantly, to clarify the evolution behavior of Ni 3 Al (γ′) phase in eutectic area (γ′–γ) under solution treatment conditions, short‐time (3 h) and long‐time (18 h) solution treatments at 1270 °C are applied and the evolution behavior is analyzed by TEM. Results show that plenty of spherical Ni 3 Al (γ′) phase appears in eutectic area (γ′–γ), with its dimensions changing little with solution time increasing. Vacancies, lattice distortion, and thermo‐stress mainly contribut to the precipitation and growth of spherical Ni 3 Al (γ′) phase.