Precipitation and growth behavior of mushroom-like Ni3Al

Abstract

Precipitation and growth behavior of mushroom-like Ni3Al phase along the dual phase (γ + γ′) and eutectic γ − γ′ area interfaces of as-cast JG4246A Ni3Al-based alloy were investigated by using short time cyclic heat treatment. Results showed that vacancies, small angle grain boundaries and dislocations formed along the dual phase (γ + γ′) and eutectic γ − γ′ area interfaces during the cyclic heat treatment, which promoted the precipitation of Ni3Al phase along this location. In addition, concentration gradient of Al elements between the eutectic γ − γ′ area and dual phase (γ + γ′) areas and the more rapid pipe diffusion provided by dislocations contributed to growth of directional mushroom-like Ni3Al phase.