| Abstract Scope |
The oxidation behavior of non-equiatomic Al30Ni20Cu15Fe25Ti10 (Al30Ni20), Al25Ni25Cu20Fe25Ti05 (Al25Ni25), and Al15Ni30Cu20Fe25Ti10 (Al15Ni30) high-entropy alloys (HEAs) was investigated at 900°C, 1000°C, and 1100°C in the laboratory air for 100 hours. The analysis included examining oxidation kinetics, microstructure, elemental distribution, EBSD and XRD patterns of the oxidized samples. It was found that the high Al concentration HEAs had BCC, dominant structure, whereas decreasing the fraction of Al is responsible for the evolution of FCC phase. Furthermore, the grain size decreased with the decrease in Al fraction. The average grain size of Al30Ni20, Al25Ni25, and Al15Ni30 samples are 125μm, 109μm, and 40μm, respectively. The oxidation rate was initially linear at all temperatures but became parabolic over longer durations. The Al30Ni20 demonstrated the highest resistance to oxidation, followed by Al25Ni25 and then Al15Ni30. Surface analysis revealed that Al2O3 was the primary oxide formed under all test conditions, along with Fe, Ti, and Cu spinels. |