Exploring 3D X-Ray Diffraction Method to Validate Approaches in Materials Modelling

Cyclic high temperature deformation, which is a precursor to creep-fatigue damage is one of the main life limiting factors in thermal power plants. Microstructurally informed models such as crystal plasticity have shown great promise in predicting cyclic plasticity and creep deformation; however, further validation of predicted meso-scale deformation is required to ensure accurate damage calculations. Here, a novel 3D X-ray diffraction (3DXRD) experiment was performed to resolve and investigate the response of individual grains within a polycrystalline material under loading at elevated temperature. Specimens were made from 316H stainless steel, which is an alloy commonly used for critical structural components in thermal power generation plants. The 3DXRD experiments were conducted at the UK national synchrotron facility, Diamond Light Source. The measurements provided positions, strain tensors, and orientations of individual grains within a gauge volume. The data generated from 3DXRD was used both as an input and for the validation of a crystal plasticity finite element model (CPFE). The results provided demonstrate the importance of microstructural information in materials modelling.