Comparative creep damage assessments using the various models

摘要

The creep fracture characteristics of a conventionally cast (CC) MARM-002 superalloy were studied for creep conditions of 1173 K/200–400 MPa using different approaches including the Kachanov-Rabotnov type continuum damage mechanics, grain boundary damage accumulation, and Chen-Argon diffusional cavity growth. A rapid improvement in creep rupture life can be achieved by reducing the Kachanov-Rabotnov damage rate (ώ) below a critical value of this rate. It is possible that a large improvement in creep resistance would be made by decreasing grain boundary damage rate rather than continuum damage rate since the minimum creep rate (έm) accelerates rapidly without changing the parameter ώ.