Application of an advanced mean-field dislocation creep model to P91 for calculation of creep curves and time-to-rupture diagrams

This work deals with the development of a comprehensive mean-field dislocation creep model and its application to the martensitic 9% Cr-steel P91. Microstructural data from literature, EBSD measurements and results from precipitate kinetic simulations serve as input for the creep simulation in addition to material- and physical constants. The model has the capability for calculating creep curves depending on their initial microstructure, stress and temperature and is thus able to deduce time-to-rupture diagrams. Side-result is the microstructural evolution during creep exposure (different types of dislocation densities, subgrains and precipitates). The capability of the model is demonstrated in P91 within the stress range of 50-110 MPa at 650°C. Simulated results agree well with experimental data from sources such as NIMS, ASME, ECCC and industrial data.