Mechanism-based modeling of thermal and irradiation creep behavior: An application to ferritic/martensitic HT9 steel. (March 2020)

• Record Type: Journal Article
• Authors: Wen, W.; Kohnert, A.; Arul Kumar, M.; Capolungo, L.; Tomé, C.N.
• Is Part Of: International journal of plasticity. Volume 126(2020:Mar.)
• Publication Date: 2020-03
• Subjects: Thermal creep -- Irradiation creep -- HT9 steel -- Crystal plasticity; Plasticity -- Periodicals; Plasticité -- Périodiques; Plasticity; Periodicals; 620.11233
• DOI: 10.1016/j.ijplas.2019.11.012
• Languages: English
• ISSNs: 0749-6419

Abstract

Abstract: In this work, the creep behavior of HT9 steel in both thermal and irradiation environments is predicted using an integrated modeling framework. Multiple physical mechanisms such as diffusional creep and dislocation climb are incorporated into crystal plasticity calculations using the Visco-Plastic Self-Consistent (VPSC) approach. Climb velocities are informed by mean field rate theory laws in place of empirical power law formulations. More interestingly, the climb velocities explicitly consider the contribution of irradiation-induced point defects, i.e., stress induced preferential absorption (SIPA) effect. The developed expressions are shown to apply under conventional thermal creep and to the more complex irradiation conditions as well. This physically-informed, mechanism-based model is used to simulate the creep strain evolution of HT9 pressurized tubes under various loading conditions. It is demonstrated that the experimental behavior of this material reported in the literature is well described by this theoretical framework. The role of each relevant mechanism is discussed. Highlights: Mechanistic model is developed to predict the thermal and irradiation creep response. Developed rate theory-based dislocation climb law accounts the contribution of irradiation-induced point defects. Thermal and irradiation creep predictions of HT9 alloy agree well with the experimental literature. Individual contributions of glide, climb and diffusional creep modes to the overall creep responses are analyzed.