Characterization of Al-Co-Cr-Fe-Mn-Ni High-Entropy Alloy Coating Fabricated onto AA5083 Using Wire-Arc Additive Manufacturing

Abstract

Fabrication of thick (more than 3 mm) hard coatings on Al-Mg alloys might provide better performance in terms of increased durability, wear resistance and hardness compared with the unmodified material. In this study we fabricated Al-Co-Cr-Fe-Mn-Ni high-entropy alloy coating by wire-arc additive manufacturing onto AA5083 substrate. The aim of this study is to investigate the microstructure and mechanical properties of the coating and its influence on the substrate. Scanning electron microscopy and transmission electron microscopy were used to characterize the microstructure and elemental composition of the obtained coating. Microhardness and tribological tests were implemented to evaluate the mechanical properties. The results showed homogeneous distribution of the elements alongside the transversal direction in the coating which has the following average chemical composition: Al 8 at. %, Co 28 at. %, Cr 13 at. %, Fe 33 at. %, Mn 3 at. %, Ni 15 at. %. The wear rate of the coating decreased by ~five times comparing with the substrate, while the Vickers hardness improved by ~three times. The highest level of hardness accounting for 1010 ± 80 HV was observed in the transition zone between the coating and the substrate which might be attributed to high micro- and macrostress levels appeared in this zone. The study showed the practical applicability of wire-arc additive manufacturing method to fabricate a high-entropy alloy on Al-Mg substrate.

Keywords

• high-entropy alloy
• gas metal arc welding
• wire-arc additive manufacturing
• Al-Co-Cr-Fe-Mn-Ni
• aluminum alloy
• coating