Effect of refractory elements and Al on the high temperature oxidation of Ni-base superalloys and modelling of their oxidation resistance

The oxidation resistance of Ni-Co-Cr-Al-W-Mo-Ta-Re-Ru alloys is evaluated by cyclic oxidation at 1100 °C and modelled using an artificial neural network. The database required for the modelling was constructed using design of experiment (the Box-Behnken method) followed by oxidation experiments. The obtained model with a 7-10-1 architecture exhibits consistent prediction of the experimental data (R = 0.999). Cr and Al enhance the oxidation resistance by promoting the formation of a protective NiAl2O4 layer. Mo and Ru are detrimental to the oxidation resistance. W, Ta and Re exhibit complex behaviours depending on the contents of other alloying elements.