Self-consistent modelling for neutron scattering applications

Research Project, 2017 – 2019

Self-consistent modelling based on crystal plasticity is commonly used to analyze the detailed response of polycrystals to externally imposed deformation during neutron scattering experiments. The aim of the project is to develop and implement a state-of-the-art self-consistent framework capable of handling the specific conditions occurring during high-temperature and thermo-mechanical deformation conditions, which will accessible at future ESS beamlines such as BEER. This includes phenomena such as time-dependence (stress relaxation, creep), varying temperatures, and complex strain paths. The code should be able to track the plane-specific micro-strains in a polycrystalline aggregate during deformation, starting from an initial set of grains with prescribed orientations. In particular, we foresee the need for an elastic-viscoplastic self-consistent model with temperature dependent crystal plasticity formulation, capable of treating multi-phase cubic materials, including phases with crystallographic relationships (two-site formulation). Typical target materials are high-temperature alloys such as austenitic steels, precipitation strengthened superalloys and multi-component high entropy alloys. Another important part is the interface to experimental data and optimization routines for parameter estimation.