Abstract:Eutectic high entropy alloys (EHEAs) have high temperature stability, good mechanical properties, and are promising for tribological applications at high temperatures. To study the high temperature lubrication behavior, Fe₂₂Co₂₆Cr₂₀Ni₂₂Ta₁₀-(BaF₂/CaF₂)_x (x=3-20, wt.%) composites were prepared by spark plasma sintering (SPS), with BaF₂/CaF₂ eutectic powder used as solid lubricant. The lubrication behavior and mechanical properties were studied at both room and high temperatures. With the increase of the content of BaF₂/CaF₂ eutectic powder, the friction coefficients and the wear rates of the composites at 600 and 800 °C decrease significantly. The composites with eutectic powder content of 15 and 20 wt.% have the best lubricating performance at 600 °C, with low friction coefficient and wear rates, mainly due to the good mechanical properties of EHEA matrix, the lubrication effect of BaF₂/CaF₂ phase and the oxides formed on the worn surface.

Key words: eutectic high entropy alloy; self-lubricating composite; BaF₂/CaF₂ eutectic powder; tribological properties; microstructure