Tribological behavior of an AlCoCrFeNi2.1 eutectic high entropy alloy sliding against different counterfaces

Tribological behavior of the model AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) sliding against different counterfaces including Al2O3, Si3N4, SiC ceramics and GCr15 steel at room temperature (RT), and particularly SiC at elevated temperatures were investigated. Our EHEA was found to maintain high hardness (＞197 HV) up to 900 °C. The RT tribology tests show that the friction and wear of the EHEA are slightest when against SiC. The wear rates of the EHEA increases monotonously from RT to 900 °C, but the friction coefficient drops sharply (＜0.35) when the temperature exceeds 600 °C. This is attributed to the enhancing in the oxidative wear and the formation of deformed fine-grained layer beneath the worn surface. [Display omitted] •Tribological behavior of the AlCoCrFeNi2.1 EHEA against different counterfaces was investigated.•The EHEA/SiC tribo-pair shows the optimal compatibility at RT.•The high hardness of over 197 HV of the EHEA could be maintained up to 900 °C, superior to the Inconel 718 superalloy.•The EHEA exhibits good wear resistance over a wide temperature range from RT to 900 °C.