20 likes | 180 Views
GOALI: Pt-Enriched g + g Bond Coats for Next-Generation Single-Crystal Ni-Base Superalloys Ying Zhang, Tennessee Technological University, DMR 0504566.
E N D
GOALI: Pt-Enriched g+g Bond Coats for Next-Generation Single-Crystal Ni-Base SuperalloysYing Zhang, Tennessee Technological University, DMR 0504566 Single-phase b-(Ni,Pt)Al coating has been an accepted industrial standard as the bond coat in state-of-the-art thermal barrier coating (TBC) systems to protect superalloys against high-temperature oxidation. However, it faces challenges when applied to single-crystal superalloys with increased levels of refractory metals (the 3rd- and 4th-generation superalloys), due to formations of brittle topologically close-packed phases and secondary reaction zones. The collaborative research between Tennessee Tech University, GE Aircraft Engines, and Oak Ridge National Laboratory (ORNL), is to explore a new Pt-enriched +' bond coat system, which is expected to offer advantages such as higher creep strength, better compatibility between coating and superalloy substrate, improved metallurgical stability, and reduced manufacturing cost. Current research focuses on investigation of the oxidation behavior of Pt-enriched +' coatings: cyclic oxidation tests with 1h cycles at 1100-1150C • Effect of the substrate composition • Three variants of single-crystal superalloy René N5 designated as N5HS (higher-sulfur), N5LS (lower-sulfur) and N5Y (plus-Y). • One composition of the directionally solidified alloy René 142 • Initial Pt thickness: ~ 7mm • Effect of Pt content • Coatings with two different Pt contents were prepared by electroplating 7±1 m Pt (standard thickness) or 12±1 m Pt (thicker Pt) onto superalloy discs
GOALI: Pt-Enriched g+g Bond Coats for Next-Generation Single-Crystal Ni-Base SuperalloysY. Zhang, Tennessee Technological University, DMR-0504566 Effect of Substrate Composition Effect of Pt Content Oxidation Test at 1100C Oxidation Test at 1150C • Increasing the initial Pt thickness to 12 mm appeared to improve the oxidation behavior of the g+g coatings. • The Pt-enriched g+g coatings are more sensitive to superalloy trace elements (especially Hf & S) than b-NiPtAl coatings.