Creep rupture in a nickel-based superalloy

Smooth bar creep rupture tests were conducted under constant loads at 1033 and 1144 K using RENé 80. Creep deformation occurred dominantly by the dislocation creep mechanism, but creep rupture proceeded by the continual nucleation and growth of cavities. Rupture times were well predicted by the constrained diffusive growth model of Riedel, particularly at low applied stresses, but their temperature dependence and the Monkman-Grant product were better related to the unconstrained diffusive growth models. Interruption tests showed development of micro- cracks in the tertiary stage of creep and sometimes revealed edge cracks, the growth of which provided the creep crack growth rate.