Session: MF-16-01 Creep and Creep-Fatigue Interaction
Paper Number: 61688
Start Time: Tuesday, July 13, 2021, 05:00 PM
61688 - Introduction of First-Principles Calculations Into Fundamental Creep Models for Austenitic Steels
Austenitic stainless steels are candidate materials for future power plants, including fossil fuel-fired and nuclear power plants, where the materials are subjected to high temperatures and stresses. Creep is an important factor influencing the service security of the materials. Unlike the short-term tensile or hardness tests, creep tests often take years and consequently, predictive modeling of creep is essential. To facilitate the research and development, it is necessary to understand the long-term creep rupture life-controlling mechanism. Instead of using empirical models, fundamental models have been proposed, where the evolution of microstructure and defects are involved. Brittle creep rupture models are proposed based on the creep cavitation models. Dislocation generation, precipitation hardening contribution, solid solution hardening and splitting of dislocations are considered in models for ductile creep rupture. The parameters involved in the models are well defined. Some physical parameters could only be obtained from the first-principles calculations like the elastic constants and lattice misfit parameters. In the first-principles calculations, the open-source code EMTO (Exact Muffin Tin Orbitals) was used to compute the high-temperature total free energy, including the electronic, magnetic and vibration contribution, with CPA-DLM (Coherent Potential Approximation-Disordered Local Moment) approach, where the paramagnetic was considered. Creep rupture prediction based on the multiscale fundamental models was used for austenitic stainless steels.
Presenting Author: Junjing He Hangzhou Dianzi University
Authors:
Junjing He Hangzhou Dianzi UniversityRolf Sandström KTH Royal Institute of Technology
Jing Zhang KTH Royal Institute of Technology
Pavel Korzhavyi KTH Royal Institute of Technology
Introduction of First-Principles Calculations Into Fundamental Creep Models for Austenitic Steels
Category
Technical Presentation Only