High speed rub wear mechanism in IN-718 vs. NiCrAl–Bentonite

A matrix of rub tests with blade tip speeds and infeed rates as variables gave rub force and tip wear results. Here, the rubbed tip material (bare IN-718, Rc = 43) and the abradable coating NiCrAl–Bentonite (HR15Y = 52) were examined in the SEM and polished cross section to gain insight into the wear mechanism involved.