Model for healing of creep cavities in nickel-based superalloys under hot isostatic pressing

A healing model for creep cavities under hot isostatic pressing (HIP) is proposed, according to the healing characteristics and thermodynamic theory. The stress gradient around the cavity is considered as a driving force for atomic diffusion in this shrinkage model. The effects of HIP temperature and hydrostatic pressure on the healing kinetics of creep cavities are studied by numerically integrating the shrinkage rate equation. A useful healing map is constructed, showing the healing time as a function of temperature and pressure. This model provides a more realistic basis for the selection of appropriate HIP parameters to rejuvenate the creep damage present in high-temperature components. (C) 2012 Elsevier B.V. All rights reserved.