γ′-size effect on the deformation microstructure and texture in a Ni-based superalloy using in-situ neutron diffraction

Abstract

The γ′-size effect on the evolution of microstructure and grain rotation during tensile deformation in a polycrystalline Ni-based superalloy was investigated by in-situ neutron diffraction technique. Diffraction profile analysis was employed to evaluate the dislocation density and deformed subgrain size distribution, revealing that alloys with fine and coarse γ′ possess dislocation shearing and Orowan dislocation bypassing, respectively. The high strain hardening in the coarse γ′ specimen is attributed to the more pronounced accelerated accumulation of dislocations compared to the fine γ′ specimen. Moreover, the specimen with coarse γ′ precipitate exhibits a lower orientation rotation rate, resulting in weaker <111> and <100> fiber texture components upon tensile straining. The use of neutron diffraction combined with electron microscopy provided multiscale insights into the deformation microstructure and changes in the lattice orientation.