Microscale deformation of a tempered martensite ferritic steel:Modelling and experimental study of grain and sub-grain interactions

In this paper, a nite-element modelling framework is presented with explicit representation of polycrystalline microstructure for a tempered martensite ferritic steel. A miniature notched specimen was manufactured from P91 steel with a 20,000 hour service history and tested at room temperature under three point bending. Deformation at the microscale is quanti ed by electron back scattered di raction (EBSD) before and after mechanical loading. A represen- tative volume element was developed, based on the initial EBSD scan, and a crystal plasticity model used to account for slip-based inelastic deformation in the material. The model showed excellent correlation with the experimental data when the relevant comparisons were made.