Tribological performance of a cost-effective CrFeNiAl0.3Ti0.3 high entropy alloy based self-lubricating composite in a wide temperature range

A cost-effective HEA based self-lubricating composite was fabricated using CrFeNiAl0.3Ti0.3 as matrix and Ag as solid lubricant by hot pressing sintering (HPS), with Ag particles uniformly dispersed along grain boundaries of HEA matrix. Tribological tests revealed a remarkable impact of Ag tribo-film in reducing coefficient of friction and wear of the composites, from RT to 600 °C. 750 °C was a turning point for the change in wear mechanism from abrasive to oxidative wear. The formation of a subsurface tribo-layer and a protective oxide layer on the worn surface of CrFeNiAl0.3Ti0.3 HEA led to low wear. At 900 °C, associated with the absence of subsurface tribo-layer, Ag is not found in the oxide layer, causing an increase in the wear of composite.