Tribological properties of WMoVCrTa and W23Mo23V17Cr8Ta7Fe22 high-entropy alloys

Two new refractory high-entropy alloys (RHEAs) of WMoVCrTa and W23Mo23V17Cr8Ta7Fe22 were fabricated, and their wear test was carried out in severe sliding conditions such as wear against the hard SiC abrasive with heavy normal loads of 30 and 40 N. Wear resistance properties of the RHEAs were investigated and compared with that of high-speed steel (HSS) alloy. WMoVCrTa and W23Mo23V17Cr8Ta7Fe22 were found to have wear coefficients that were 1.9 and 2.5 times lower than those of HSS, respectively. Coefficients of friction (COF) of WMoVCrTa and W23Mo23V17Cr8Ta7Fe22 were 0.483 × 10−4 and 0.359 × 10−4 mm3/N·m, respectively, which were nearly half of the COF of HSS (0.917 × 10−4 mm3/N·m). Hence, the two RHEAs outperform the HSS in wear resistance properties. The W23Mo23V17Cr8Ta7Fe22RHEA exhibited tremendous wear resistance as its wear coefficient increased minimally by increasing the load significantly. Of the three alloys, W23Mo23V17Cr8Ta7Fe22 has the least wear volume and the lowest wear coefficient value that shows its superior wear resistance than the WMoVCrTa and HSS alloys. The major wear type identified in the two RHEAs was the abrasive wear. Emergence of substantial amount of self-lubricating wear debris aided in reducing the frictional force in the RHEAs during wear test.