Thermodynamic and kinetic modelling: Creep resistant materials

Abstract

The use of thermodynamic and kinetic modelling of microstructure evolution in materials exposed to high temperatures in power plants is demonstrated with two examples. Precipitate stability in martensitic 9-12%Cr steels is modelled including equilibrium phase stability, growth of Laves phase particles and coarsening of MX, M23C6 and Laves phase particles. The modelling provided new insight Into the long term stability of new steels. Modelling of the detrimental precipitation of Z phase Cr(V,Nb)N is described, which points to new approaches in alloy development for higher temperatures. Predictions of interdiffusion between a MCrAlY coating and an IN738 bulk alloy by multicomponent diffusion calculations provide a highly versatile tool for life assessment of service exposed gas turbine components as well as for the development of improved coatings. © 2008 Institute of Materials, Minerals and Mining.