Effect of Mo, Ta, and Re on high-temperature oxidation behavior of minor Hf doped β-NiAl alloy

•Effects of Mo, Ta, and Re on oxidation behavior of β-NiAlHf alloys are investigated.•Ta and Hf (so do Re and Hf) co-precipitate into one phase during alloy preparation.•Mo, Ta, and Re reduce the oxidation resistance in different ways.•The effectiveness of Mo, Ta, and Re depends on their concentration in the alloys.•The interaction mechanism between Ta and Hf as well as Re and Hf is discussed.

The microstructure and cyclic oxidation behavior of minor Hf-doped NiAl alloys with addition of different alloying elements including Mo, Ta, and Re were investigated. Co-precipitation of Ta and Hf as well as Re and Hf occurred during alloy preparation, whereas Mo and Hf precipitated individually into different phases. Over 0.5 at.% addition of Mo, Ta and Re had negative influence on the oxidation behavior of β-NiAlHf alloy, while the effect could be ignorable once the concentration reduced to less than 0.05 at.%. The interaction mechanism between Ta and Hf as well as Re and Hf was discussed.