Microstructure and sliding wear behavior of (AlCoCrFeNi)1-x(WC)x

In this study, (AlCoCrFeNi)1-x(WC)x high-entropy alloy composites with different WC weight ratios (x = 0, 10, 30, 50 wt%) were prepared using the gas atomization method and a vacuum hot-pressing sintering technique. The phase compositions, microstructures, and tribological properties in a wide temperature domain of the (AlCoCrFeNi)1-x(WC)x composites were evaluated over a wide temperature range. The results showed that an increase in the WC weight fraction promoted the diffusion of Fe, Co, and Ni from the body-centered cubic (BCC) and face-centered cubic (FCC) phases to generate η-carbide phases containing WC. This hindered the transformation of the BCC phase to the FCC+σ phase, resulting in a decrease in the FCC content and an increase in the BCC phase. The BCC phase further decomposed into the A2+B2 phase by spinodal decomposition. At the same time, the coupling strengthening effect of the η-carbide, BCC, and WC phases resulted in a significant increase in the hardness of the (AlCoCrFeNi)1-x(WC)x composites. The characterization of the tribological properties of the (AlCoCrFeNi)1-x(WC)x composites over a wide temperature range showed that the friction coefficient decreased with the addition of WC. In addition, the (AlCoCrFeNi)1-x(WC)x composites showed good tribological properties and wear resistance at high temperatures, i.e., the wear rate of the composites decreased significantly. This can be attributed to the formation of an oxide film on the worn surface.