Effect of Aluminide Coating on Rapture Behavior of Ni-Based Superalloy GTD-111 in High Temperature

Abstract

GTD-111 superalloys are of the newest Ni-based superalloys which because of having good stability and strength in high temperatures are used in manufacturing of hot-gas-path parts of the gas turbines. Because of severe working conditions, application of these superalloys without coating isn't recommended. For this purpose, firstly the superalloy is coated and then is used. In this paper, the effect of Aluminide coating on rapture behavior of the GTD-111 superalloy is investigated. For this purpose, a number of samples made from GTD-111 superalloy have been coated by powder cementation method and have been subjected to rapture test and have been compared to uncoated samples. The results suggest that the presence of coating causes increase of Al content in the surface and contributes in stability of γ´ which is the most important factor of superalloy strength and also causes more life cycle of this superalloy with respect to similar uncoated samples.