Comparison of Continuum Damage Laws Under Uniaxial Creep for an AISI 316 Stainless Steel

Parameters of five popular continuum damage models are fit to match their creep rate and time to rupture predictions with that of a validated micro-mechanisms based model at a high nominal stress for an austenitic stainless steel. Their predictions are then compared with that of the micro-mechanisms based model at lower stress levels. The creep-strain rate and time to failure predictions of the model due to Wen et al. (Eng Fract Mech 98:169–184, 2013) best agrees with that of the micro-mechanisms based model in the regime of dominance of creep deformation processes. At still lower stress levels, where cavitation-rate is determined by diffusion processes, the Wen et al. model predictions of creep lifetimes become excessively non-conservative. A correction based on a formula due to Cocks and Ashby (Prog Mater Sci 27:189–244, 1982) has been proposed for this regime.