Prediction of creep ductility for austenitic stainless steels and copper

Abstract

ABSTRACT For modern creep-resistant steels, ductility is primarily controlled by cavitation, since brittle rupture is dominating during long-term service. In recent years, the present authors have formulated fundamental models for nucleation and growth of cavities that have been verified to be able to describe experiments for austenitic stainless steels. These equations, together with models for dislocation creep, are used in this paper to present basic modelling results for the creep ductility of austenitic stainless steels for the first time. New results are also presented for ductile rupture, where the elongation values are mainly governed by plastic instability and necking. The Hart criterion is used to identify the strain where the instability forms. Modelling shows that the instability grows very slowly and that its size is not significant until close to rupture. These facts are used to demonstrate that ductility during ductile rupture can be predicted from necking behaviour.