Short-Term Oxidation Behavior and Mechanism of Nickel-Based Superalloy CMSX-4 at 1100° C

摘要

Nickel-based superalloys underg o oxidation in high -temperature corrosive environments, but the oxidation behavior and mechanism during the early stages remain unclear. The study investigated the oxidation behavior of nickel-based superalloy CMSX -4 of short-term oxidation in air at 1100° C,employing multi-scale characterization techniques. The results indicate that the oxidation of the CMSX-4 alloy adheres to parabolic kinetics, ultimately forming a c omplex four -layer oxide scale comprising a NiO(CoO) layer, CoCr2O4 and TiTaO4 layer, NiAl 2O4 layer, and Al2O3 layer. CoCr2O4 is formed by the reaction of CoO and Cr 2O3, while TiTaO4 is transformed from TiO2 and Ta 2O5. F urthermore, NiO reacts with Al 2O3 to generate NiAl2O4. The excellent oxidation resistance is primarily attributed to the forma tion of dense Al2O3 layer. It acts as the primary protective barrier for the alloy matrix, impeding element diffusion and preventing further oxidation.