Oxidation behavior of powder metallurgy processed AlCrNiFeMnWx tungsten-containing high-entropy alloys at isothermal temperatures

Developing materials with outstanding oxidation resistance and structural stability is essential for applications where mainly exposed to temperatures. In this context, tungsten (W) is renowned for its ability to form stable, protective oxide layers at high temperatures. Herein the present study explores the oxidation behavior of powder metallurgy processed AlCrNiFeMnWx (x = 0, 0.05, 0.1, and 0.5) high-entropy alloys (HEAs) at isothermal temperatures of 200 and 500 °C for 50 h to assess their high-temperature stability. After the oxidation tests, the phase compositions and microstructural characteristics of the HEAs were investigated to understand the effect of W contents. Thus, the present study offers valuable information for the development of materials with exceptional thermal and oxidation resistance. The oxidation behavior of AlCrFeMnNiWx HEAs was systematically investigated at 200 °C and 500 °C. The oxidation rate constants were determined to range from 4.54 × 10 −9 to 4.6 × 10 −9 g 2 /cm 4 s at 200 °C, indicating excellent oxidation resistance at lower temperatures. At 500 °C, the rate constants increased from 6.48 × 10 −8 to 1.023 × 10 −8 g 2 /cm 4 s reflecting a temperature-dependent oxidation response. These findings highlight the influence of tungsten content in enhancing the oxidation resistance of HEAs, providing insights for their application in high-temperature environments.