Gas and steam turbines as well as solid oxide fuel cell (SOFC) systems must provide high reliability during long-term service and need to sustain numerous start-stop cycles and load changes. The latter aspect is essential in the case of aero engines and SOFC systems, but becomes -due to the increasing amount of fluctuating renewable energy based power generation- of increasing concern for gas and steam power plants. Load changes induce time dependent temperature gradients which result in thermo-mechanical fatigue loadings that strongly influence service life of key components, e. g. turbine blades or SOFCs. In case of metal-ceramics compound components, such as turbine blades with thermal barrier coatings or metal-ceramic braze joints in SOFC stacks, the thermal mismatch between metal and ceramics induces a further load component which needs to be considered for design. Furthermore, oxide layers growing on metallic components during high-temperature loading have significant influence on the fatigue behavior.
The working group therefore investigates the isothermal and thermo-mechanical fatigue behavior of metallic high temperature materials and of metal-ceramic compounds for power plants and SOFCs.