High temperature oxidation behavior of Cr-Mn-Fe-Co-Ni high entropy alloy

By Young-Kyun Kim, Y. Joo, Hyoung-Seop Kim, Kee‐Ahn Lee. Intermetallics (Barking), 2018

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Abstract This study examined the surface oxidation properties of Cr-Mn-Fe-Co-Ni high entropy alloy (HEA) at high temperatures (900 °C, 1000 °C, 1100 °C/24 h) in the 21%O2 and 79%N2 atmosphere. An initial observation of microstructures confirmed that they consisted of random FCC solid solution, and the average grain size was measured at 245.5 μm. High-temperature oxidation tests of the Cr-Mn-Fe-Co-Ni HEA showed that its weight gained by 1.76, 4.45, and 9.08 mg/cm2 at 900 °C, 1000 °C, and 1100 °C, respectively, and all three temperature conditions represented typical parabolic curves. Observation of its surface found that Cr2O3 and Mn2O3 were main oxides on a specimen tested at 900 °C, while (Mn, Cr)3O4 and Mn3O4 were mostly shown to be main oxides on a specimen tested at 1000 °C and 1100 °C, despite the presence of Cr2O3. The high-temperature oxidation behavior of Cr-Mn-Fe-Co-Ni HEAs was found to have been largely affected by Cr and Mn elements. The resultant kirkendall pore generation, change in the concentration of elements, internal oxidation and Mn2O3 → Mn3O4 transformation were found to affect the oxidation resistance of Cr-Mn-Fe-Co-Ni high entropy alloy.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/946fc5fe44d08ed81d044a0a1a328cf51ae8750f