Phase Stability of Ni/Ni<inf>3</inf>Al Multilayers Under Thermal Annealing and Irradiation

Nickel-based superalloys with L12-ordered Ni3Al precipitates exhibit excellent high-temperature mechanical properties and corrosion resistance. Here we studied the phase stability of a Ni/Ni3Al multilayer under high-temperature thermal annealing and Ni ion irradiation. Ni/Ni3Al multilayers with order–disorder interfaces were fabricated by magnetron sputtering at 773 K. Thermally induced interdiffusion and precipitation occurred under thermal annealing at 1073 K for 1 h. Ni ion irradiation at 773 K to a dose of 2 × 1016/cm2 led to chemical intermixing across the Ni/Ni3Al interface, although the Ni3Al layer remained ordered. The results of this study provide insight into the understanding of disorder, recovery, and dissolution processes occurring in ordered intermetallic compounds in extreme environments.