Dry-sliding tribological properties of AlCoCrFeNiTi_0.5 high-entropy alloy

High-entropy alloys (HEAs), with a new alloying concept, could possess many unique mechanical and functional properties. The current work investigated whether one such alloy offers potential for bearing surfaces under dry conditions. The dry, reciprocating sliding wear characteristics of AlCoCrFeNiTi_0.5 alloy were investigated under various applied loads and sliding speeds. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were utilized to characterize internal structure and wear surfaces of the alloy, respectively. It is found that the AlCoCrFeNiTi_0.5 alloy preserves better wear resistance than Fe₇₇Ni₂₃ solid solution alloy, Ti-46Al-2Cr-2Nb intermetallic alloy, or a wear-resistant steel AISI 52100, especially under higher loads. The wear rate increases slowly with the applied loads increasing and keeps steady under different sliding speeds. The wear mechanisms are abrasive wear, adhesive wear and oxidative wear. The nano-sized Fe–Cr solid solution and Al–Ni–Ti rich intermetallic phase precipitated in the dendritic regions and the formation of oxidation play important roles in the good wear resistances of this high-entropy alloy.