Sine Hyperbolic Models and Their Applicability Towards Creep Deformation Behaviour of 9% Chromium Steels

Two different variants of creep models have been developed. In Model-I, sine hyperbolic kinetic law defining primary and secondary creep deformation has been added to tertiary creep rate for complete description of creep strain–time trajectories. In Model-II, evolution of damages such as subgrain growth, forest dislocation density, internal stress and precipitate coarsening have been coupled into the sine hyperbolic creep rate relation in the framework of phenomenological based approach for describing three stages of creep deformation. Applicability as well as implications of both the models has been examined for creep deformation of P9 steel for 150 MPa at 793 K.