Revealing the Void Formation Mechanism during Superplastic Deformation of a Fine-Grained Ni-Co-Base Superalloy

The mechanism behind void formation during superplasticity remains a subject of uncertainty.This study presented a novel insight into the void formation in a fine-grained Ni-Co-based superalloy during superplasticity.It was observed that the dissolution ofγ′-particles resulted in the creation of vacancies due to differences in atomic size between the matrix and the particles.These vacancies acted as inclusions,leading to the formation of micro-voids.Notably,excessive void formation correlated with higher particle dissolution was experimentally observed,highlighting a direct relationship between void formation and particle dissolution.