Influence of cyclic strain on life of a PVD TBC

A thermal mechanical fatigue (TMF) test has been developed to determine the effect of strain on the life of a thermal barrier coating. TMF tests were performed with different temperature–strain phasing and different applied strain levels to vary the imposed strain range on the coating and thus separate strain dependence of life from oxidation effects. Results for a single crystal superalloy coated with an EB–PVD yttria-stabilized zirconia layer showed that as the compression on the coating at minimum temperature was increased the cycles to spall decreased, following a power law dependence on total strain range.