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6344 |
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Creep behavior of IN100 and M247LC-SX superalloys coated with HVOF Ta-containing NiCoCrAlY. |
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Alma Gabriela Mora García* / Centro de Investigación y de Estudios Avanzados del Instituto Politecnico National, Mexico Juan Muñoz Saldaña / Centro de Investigación y de Estudios Avanzados del I.P.N. , Mexico Mike Mosbacher/ Universität Bayreuth, Germany Julia Hastreiter/ Universität Bayreuth, Germany Rainer Völkl/ Universität Bayreuth, Germany Uwe Glatzel/ Universität Bayreuth, Germany |
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Polycrystalline IN100 and single crystal M247LC superalloy samples were coated with Ta-containing NiCoCrAlY by high velocity oxy-fuel thermal spray. Creep tests were performed on coated and uncoated IN100 and M247LC SX superalloys and focusing on the influence of superalloy thickness on their creep behavior. Particularly, the creep tests were carried out at 980 ºC under a constant load of 150 MPa in air to address the influence of the substrate thickness on the creep strength behavior irrespective of the superalloy. The superalloy thickness was varied with respect to the coating. The results show a thickness debit effect in both coated superalloys. The smaller the specimen thickness, the lower the creep resistance and the higher the minimum creep rate. The M247LC SX superalloy in either coated or uncoated conditions showed better creep behavior compared to IN100. The contribution of the coating to the creep resistance on both superalloys was found to be neglectable. The primary mechanism responsible for stress-rupture life in IN100 superalloy was related to the behavior of grain boundaries in thin sections. The set of coated and uncoated IN100 superalloys showed the lowest creep time to failure compared to those with M247LC SX superalloy. In addition, the influence of the oxidation on the failure behavior of the specimens is presented in this work. |