Advanced MCrAlY Alloys with Doubled TBC lifetime Part II Unique properties of advanced alloys

Advanced new bond coat alloys with more than doubled TBC lifetime have been developed. The causes of the extended thermal cycle lifetime have been investigated by evaluating thermal expansion coefficient, examining evolution of TGO and microstructure of bond coats during thermal cycling by using high resolution SEM with EBSD. It is concluded that the extended thermal cycle lifetime is attributed to the unique properties of new alloys, such as remarkably lower coefficient of thermal expansion (CTE), lower weight fraction of β phase, higher hardness, lower aluminum migration rate and the absence of mixed / spinel TGO oxides