Insights into the effects of grain size variation and FCC phase formation on the oxidation behavior of laser additively manufactured BCC AlCoCrFeNi high entropy alloy

• Published in: Corrosion science 2024-10, Vol.239, p.112416, Article 112416
• Main Authors: Zhou, Ziyi, Zhang, Xue, Peng, Xiao, Xie, Yun, Yang, Shouhua, Li, Haonan, Guo, Hongbo
• Format: Article
• Language: English
• Subjects: Heat treatment; High-entropy alloys; High-temperature oxidation; Laser additive manufacturing
• ISSN: 0010-938X
• DOI: 10.1016/j.corsci.2024.112416

The laser melting deposition technique was employed to fabricate a high entropy alloy of body-centered-cubic (BCC) AlCoCrFeNi with varying grain sizes. Subsequent annealing or quenching heat-treatment resulted in the precipitation of additional fine face-centered-cubic (FCC) phases. Oxidation at 1000 °C showed that the refinement of grains unexpectedly weakened the ability of the BCC alloy to sustain steady-state growth of an external Al2O3 scale, while the formation of FCC phases proved beneficial in promoting and maintaining exclusive and consistent growth of Al2O3 scale. The reasons behind these findings were thoroughly elucidated based on microstructural investigations of the formed oxide scales. •A BCC AlCoCrFeNi high entropy alloy with various grain sizes was produced using laser additive manufacturing.•The as-printed BCC alloy was converted to a BCC/FCC one through annealing or water quenching treatments.•The grain refinement of the BCC tends to increase the oxidation rate in air at 1000 °C.•Additional FCC phase formation within the alloy leads to a significant reduction in the oxidation rate.