A void growth model of multiaxial power-law creep rupture involving the void shape changes

Abstract

A micro-mechanism based void growth model involving the void shape change during the creep deformation is proposed, referring to the traditional Cocks–Ashby (C–A) model framework, for multiaxial power-law creep rupture prediction. Accordingly, an improved prediction for creep lifetime and multiaxial creep ductility are derived. Results indicate that the creep life and creep ductility are significantly affected by the void shape evolution in the low stress triaxiality range. By contrast, such an effect could be neglected under the situation of high stress triaxiality. In addition, a large fraction of creep ductility is consumed during the tertiary creep stage. A good agreement has been achieved between the proposed model and the collected experimental data.