Effect of MCrAlX overlay coating on mechanical properties of Ni₃Al based alloy IC6

The NiCrAlY, NiCoCrAlY and NiCoCrAlYHf overlay coatings were deposited on Ni₃Al based alloy IC6 used by arc PVD method, as well the tensile properties at room temperature and the stress rupture lives of coated and uncoated alloy IC6 were tested. The experiment results show that the three MCrAlX overlay coatings only make an effect on the tensile properties insignificantly, and the NiCoCrAlY and NiCoCrAlYHf coating also have no evident effect on the stress rupture lives, but the NiCrAlY coating make the stress rupture life of alloy IC6 decrease obviously. We studied the microstructure and chemical composition of the NiCrAlY coating before and after the stress rupture test by SEM and EPMA. There is regular-lumped AlN phase appearing in the coating, so it maybe the AlN phase results in the decreasing of the stress rupture life of alloy IC6.