Inelastic material behavior of advanced chromium steels

Advanced chromium steels are widely used materials for components in power plants. Due to their complex microstructure these steels show a good creep resistance. Nevertheless a reliable prediction of the deformation state caused by temperature and thermal load is essential in the design process of power plant components. To this end a material model based on a continuum mixture theory approach is utilized. Therefore the microstructure is represented as an inelastic hard and inelastic soft phase to derive constitutive equation of the mixture. Furthermore evolution of the microstructure is described by evolution equation of inner state variables, which enter the constitutive equation. Material model parameters are calibrated against uni-axial material tests for different stress and temperature levels. For verification purpose the calibrated material model has to predict material behavior for non constant stresses. Finally the material model will be implemented in a commercial FE-code to perfume the structural analysis of component.