Degradation of MCrAlY Coating and Substrate Superalloy During Long Term Thermal Exposure

Abstract Reliability and service life of hot gas path components of a gas turbine are limited by the degree of coating and substrate material degradation that occurs during service. MCrAlY type coatings and Ni-base alloys are widely used in the industry. In this study, the effect of long term thermal exposure with and without stress on a blade material, U520 and on a MCrAlY coating has been investigated. Microstructural degradation of coating and U 520 material are presented as a function of time, temperature and stress. These results are compared with the degradation observed in service-exposed blades.