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Current Status of Research on the Oxidation Behavior of Refractory High Entropy Alloys
Author(s) -
Gorr Bronislava,
Schellert Steven,
Müller Franz,
Christ Hans-Jürgen,
Kauffmann Alexander,
Heilmaier Martin
Publication year - 2021
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.202001047
Subject(s) - high entropy alloys , corrosion , materials science , spallation , alloy , refractory metals , refractory (planetary science) , oxide , thermal oxidation , metallurgy , high temperature corrosion , nanotechnology , physics , quantum mechanics , neutron
Refractory high entropy alloys (RHEA) are considered as novel promising high‐temperature materials for structural applications at ultrahigh temperatures primarily due to their attractive mechanical properties. By contrast, the oxidation behavior of RHEA has raised concern owing to pest oxidation, significant weight changes, scale spallation, or even complete oxidation at elevated temperatures. Herein, the currently available literature on high‐temperature oxidation behavior of RHEA is reviewed with respect to alloy composition, mass changes, corrosion products, and scale constitution. While many RHEA indeed suffer from poor oxidation resistance similar to that of pure refractory metals, some RHEA exhibit very good protectiveness, which is attributed to the formation of either well‐known protective scales such as α‐Al 2 O 3 or rarely encountered complex oxides such as CrTaO 4 . Thermodynamic and kinetic aspects of oxide formation and growth are discussed to understand the oxidation mechanisms typical of RHEA. Further research directions with respect to additional in‐depth studies elucidating the oxidation mechanisms as well as the further consequent improvement of the oxidation resistance of RHEA are developed from the current intermediate stage of research in the field.