Nano- and micro-mechanical properties and corrosion performance of a HVOF sprayed AlCoCrFeNi high-entropy alloy coating
Date
2022
Authors
Meghwal, A.
Singh, S.
Anupam, A.
King, H.J.
Schulz, C.
Hall, C.
Munroe, P.
Berndt, C.C.
Ang, A.S.M.
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Journal of Alloys and Compounds, 2022; 912:1-16
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Abstract
In this work, a gas atomized feedstock was used to fabricate an AlCoCrFeNi HEA coating using the high-velocity oxygen fuel (HVOF) process. The coating’s resistance to room temperature surface degradation wasevaluated using dry sliding wear and seawater corrosion testing. The coating retained the feedstock phasestructure with negligible in-flight oxidation and was composed of a majority BCC phase with a minor B2phase, resulting in a high micro- and nano-hardness of ~7 GPa. These observed phase compositions wereconsistent with thermodynamically calculated phase predictions using a CALPHAD model.
Microstructure-mechanical property mapping revealed uniform microstructural characteristics. However, the multiscale wear resistance of the coating was critically affected by the presence of the hard BCC/B2 phase composition, which led to severe brittleness. Combinatorial assessment of the worn surface, wear debris and counter body indicated that wear was dictated by a combination of abrasive, surface fatigue, tribo-oxidation and adhesive wear. In addition, the coating exhibited superior general corrosion resistance compared with conventional SS316L, but the selective dissolution of the B2 phase preceded poor localized corrosion resistance, ultimately leading to pitting corrosion.
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Copyright 2022 Elsevier
Access Condition Notes: Accepted manuscript is available open access