The effect of alloying elements on oxide scale spallation of multicomponent Co-based superalloys

Highlights: • Low cyclic oxidation resistance of binary Co-Al, Co-W and ternary Co-Al-W alloys. • Ni-addition reduces oxide spallation. • Incorporation of Ni to oxide scale phase constituents. • Increase of Al and W contents improves oxidation resistance. • Similar oxidation behavior of as-cast and as-aged alloys. The characterization of high temperature cyclic oxidation behavior of as-cast and as-aged Co-(Ni)-Al-W alloys, and the influence of alloying elements on oxide spallation resistance have been investigated in this study. The cyclic oxidation and oxide scale morphology of the alloys are analyzed from 700° to 900°C. It has been observed that the ternary Co-Al-W alloys are prone of oxide scale spallation and increasing the Al, W and Ni contents improves the cyclic oxidation resistance of the alloys. The structural effect of Ni on oxidation performance is related to its introduction to single and complex oxides present in a scale.