Study of wear and friction properties of a Co-free CrFeNiAl0.4Ti0.2 high entropy alloy from 600 to 950 °C

Sliding friction and wear performance of an economical Co-free CrFeNiAl0.4Ti0.2 high entropy alloy was studied over a wide temperature range. The homogenised alloy comprised a mixture of three distinct phases: B2, BCC and FCC phases. Sliding temperature had a significant influence on friction coefficient, wear rate and worn surface morphology. The maximum friction coefficient and minimum wear rate are achieved at 800 °C. An increase in friction coefficient and a drop in wear rate are observed when temperature is below 800 °C, however, an opposite trend is seen above 800 °C. The main wear mechanism is abrasion at 600 °C, but oxidation contributes more at higher temperatures. Formation of oxide layers and subsurface tribo-layers improves wear resistance at high temperatures.