Séminaires > Effect of impurity S and its suppression method on oxidation resistance of Ni-base single crystal superalloys
Date : 12 Mai 14h
Lieu : Salle Barthélémy
Résumé :
Ni-base single-crystal superalloys, used as turbine blades for the hottest regions of the jet engines and gas turbines, exhibit excellent mechanical and environmental properties at high temperatures. These alloys contain several rare metals, and with the increase in the manufacturing cost, recycling of these alloys is crucial. However, impurities, especially sulfur (S), enter the alloy during usage, drastically decreasing its oxidation resistance. Therefore, methods to remove these impurities while recycling are needed. One method is to use CaO crucibles during the melting process before casting. Compared to the conventional melting method using Al2O3 crucibles, the oxidation resistance of molten alloys melted using the CaO crucible was higher, even when the impurity S contents of the samples were about the same. However, its mechanism was unclear. In this study, we clarified how the impurity S contents, as well as the different types of crucibles used during melting, can affect the oxidation resistance of Ni-base superalloys at 800 ℃ and 1100 ℃.