Tribological behavior of microwave synthesized high entropy alloy claddings

In present work, we investigated the tribological behavior of the high entropy alloy (HEA) claddings under different degrading environments viz, slurry erosion-corrosion, liquid impingement erosion, electrochemical corrosion, and sliding wear. The HEA claddings were developed by varying Al fraction (AlxCoCrFeNi) (x = 0.1 to 3) using microwave processing. The claddings were composed of cellular structure with intermetallic phases segregated in the intercellular region. Variation in Al content showed significant influence on the microstructure and mechanical properties. The hardness of the claddings increased with an increase in Al fraction with a maximum value of 624 HV observed for the cladding containing three molar Al. Correspondingly, the fracture toughness showed an opposing trend. All claddings showed better wear resistance than SS316L with equimolar composition outperforming other counterparts. The equimolar HEA cladding showed 3 to 23 times higher wear resistance compared to SS316L steel depending upon test conditions. Inimitable wear resilience of the equimolar composition was attributed to its high hardness and strain-hardening ability. Surface morphologies of the tested claddings indicated the presence of ductile-brittle mixed damage modes. The tested surfaces showed numerous pits and cracks with delaminated secondary phase. Presence of groves and signs of delamination were also observed in case of sliding wear. The results of the present work show that microwave synthesized equimolar HEAs can effectively counter different tribological forms.