Influence of copper and aluminum substitution on high-temperature oxidation of the FeCoCrNiMn “Cantor” alloy

Abstract

In this study, the oxidation behavior of FeCoCrNiMn (HEA + Mn) is compared to three modified HEAs manufactured by substituting Mn with Al, Cu, or Al + Cu. Oxidation tests were conducted between 600°C and 800°C for up to 500 h in synthetic air. Substitution of Mn leads to a significant improvement in the oxidation resistance for the three modified HEAs. For FeCoCrNiCu (HEA + Cu), a local attack of a Cu-rich phase was observed, leading to the formation of CuO blisters on the surface. The FeCoCrNiAl (HEA + Al) alloy was characterized by the formation of a thin Al2O3 surface layer for all temperatures. However, for the HEA + Al alloy the formation of AlN was observed after 300 h at 800°C, leading to a partial breakdown of the protective scale. FeCoCrNiCuAl (HEA + Cu + Al) by far showed the best oxidation resistance, characterized by the formation of a highly protective Al2O3 scale that effectively inhibited nitrogen penetration into the metal subsurface and local attack of the Cu-rich phase.This article is published as Bürckner, Mary‐Lee, Lukas Mengis, Emma MH White, and Mathias C. Galetz. "Influence of copper and aluminum substitution on high‐temperature oxidation of the FeCoCrNiMn “Cantor” alloy." Materials and Corrosion 74, no. 1 (2023): 79-90. DOI: 10.1002/maco.202213382. Copyright 2022 DECHEMA. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission. DOE Contract Number(s): AC02-07CH11358