Creep in material science is a phenomenon whereby a material is put under a stress below its yield stress but at high temperatures and over a long period of time, begins to plastically deform. This deformation eventually leads to the growth and coalescence of pores which ultimately results in crack damage and material failure. Creep loading is of particular significance in the power plant industry where steels are put under high temperatures and pressures over several decades of service. Any failure of material in power plants could lead to catastrophic outcomes.
Although numerous tests have been carried out to predict the creep behaviour of materials, they have often been inaccurate as extended periods of testing are required for a complete understanding of creep phenomena. Numerous attempts have been made to model the creep behaviour based on a fundamental understanding of material microstructure. Creep models have generally been based on diffusion of vacancies and atoms within the material as well as the generation and movement of dislocations. However, many of these models have proven to be unreliable as they are based on too many assumptions. Furthermore, the models tend to be specific to certain materials and do not incorporate all the aspects of the microstructure and its evolution. Therefore, the objective of this research is to improve upon existing creep models by incorporating the material microstructure towards ultimately developing a standard creep model.