A microstructure-based study of irradiation hardening in stainless steel: Experiment and phase field modeling

Irradiation hardening plays an important role in the mechanical property and service lifetime of structural materials in nuclear power plants. The irradiation hardening of irradiated 316H under room temperature and 550 degrees C was investigated by TEM and nano-indentation, with a lower hardening degree for 316H irradiated under 550 degrees C. Dislocation loops and small bubbles were the main causes for the irradiation hardening in the present study. The prediction of irradiation hardening was influenced by the density and size of dislocation loops. Based on the dispersed barrier hardening model and irradiation microstructure, a phase field model coupled with crystal plasticity was proposed to predict the irradiation hardening. With consideration of an additional hardening of dislocation loops, the predicted results agreed very well with the experimental stress vs. strain curves and the increase in yield stress after irradiation. A unified barrier strength was determined for 316 austenite stainless steel in phase field model. Compared with the dispersed barrier hardening model, the unified barrier strength made the phase field model an effective way to predict irradiation hardening, reducing the uncertainty of assessment. (c) 2022 Elsevier B.V. All rights reserved.