FAILURE OF THERMAL BARRIER COATING SYSTEMS UNDER CYCLIC THERMOMECHANICAL LOADING

摘要

The failure mechanisms of thermal barrier coating(TBC)systems applied on gas turbine blades and vanes investigated using thermomechanical fatigue(TMF)tests and finite element(FE)modeling. TMF tests were performed at two levels of applied mechanical strain, namely five times and three times the Critical in-service mechanical strain of an industrial gas turbine. TMF testing under the higher mechanical Strain of air plasma-sprayed(APS)and electron beam-physical vapor deposition(EB-PVD)coated samples Showed that both system failed after a similar number of cycles by cracks that initiated at the bond Coat/thermally grown oxide(TGO)interface and propagated through the bond coat to the substrate.