Oxidation behaviors of a Ni–Cr–W based superalloy with different microstructures

Oxidation behaviors of a Ni–Cr–W based superalloy were investigated in terms of microstructural characteristics. It was found that the specimens with small grains present a better oxidation resistance owing to their higher density of grain boundaries. Based on analyses of the products of oxidation, the oxidation kinetics, the morphologies and the structures of oxide scales, the oxidation mechanisms correlated with the outward diffusions of metal cations were proposed. The results of this work indicated that grain refinement is one of effective measures to enhance the oxidation resistance of the investigated alloy.