Evolution of μ phase in a Ni-based alloy during long-term creep

Abstract The metastable σ phase dissolves gradually and supports the nucleation and growth of not only μ phase but also M 23 C 6 carbides in its close vicinity during long-term creep. It is found that some fractions of phase interfaces (about 15%) between μ phase and matrix have significant Cr enrichment, probably caused by the nucleation of μ phase originating from the dissolution of σ phase. Other phase interfaces (about 85%) without Cr enrichment can be attributed to the independent nucleation of μ phase originating from the matrix. The effect of the μ phase nucleation on cracking behavior has been discussed emphatically.