Insights into the static friction behavior of Ni-based superalloys

The static friction coefficient was overall higher for the experiments at elevated temperatures for all counterface materials against Inconel 718. Ex situ analysis by means of FIB/SEM and XPS revealed the formation of metal oxide layers on the surfaces of the different alloys after testing at elevated temperature. In addition, atomistic simulations were performed in order to elucidate the interfacial mechanism leading to the differences in static friction. The observations of the simulations correlated well with the experiments, where the shear strength of the frictional interfaces was evidently higher for the oxide-on-oxide systems compared to the nickel-on-nickel.