IGTC-71 Coating Design and Evaluation of High-Temperature Strength(Session C-6 SURFACE COATING)

概要

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It is necessary to establish an adequate coating design for improving the coating performance of gas turbine components. In this paper, crack growth behaviors of high-temperature protective coatings were investigated from the view point of stress intensity factor and residual stress characteristics using finite element method. And the influence of such coatings, which were coated by low-pressure plasma spraying, on creep lives and fatigue lives of superalloys, equiaxis IN738LC, directional solidified CM247LC and single-crystal CMSX-2 were evaluated. From the analytical results, MCrAlY coatings with low Young's modulus and low thermal expansion coefficient were useful to reduce the crack growth rate in the coatings. MCrAlY coatings had no significant influence on creep lives and low-cycle fatigue lives of any substrates, but high-cycle fatigue lives tended to slightly reduce by presence of the coatings, because of the specimen surface roughness and residual grits before spraying.