Intergranular cavitation during creep in astroloy

Abstract

Intergranular cavitation during creep in low carbon Astroloy, a typical nickel-base superalloy with a γ-γ' microstructure, was studied in a temperature range of 0.60–0.65 T_m. Because the grain boundary carbides could be distributed quite uniformly on all grain boundaries regardless of their structure, cavitation which results from them was also very uniform. The cavity nucleation rate was found to be directly proportional to the average creep rate. Throughout their growth the cavities retained a spherical-caps shape and their overall growth rate correlated best with a model of unconstrained growth.