Atomic insight into tribological behavior of AlCoCrFeNi high entropy alloy at various nanoscratching conditions

High-entropy alloys (HEAs) have garnered significant interest in recent years due to their exceptional properties. Among the HEAs, the AlCoCrFeNi HEA has been extensively studied due to its outstanding thermal stability and mechanical properties. However, limited attention has been given to its tribological behavior under high temperature and high velocity conditions. In this study, we first investigate the effect of temperature, scratching velocity, and scratching depth on the tribological behavior of AlCoCrFeNi HEA at the atomic level employing molecular dynamics method. The AlCoCrFeNi HEA exhibits good wear resistance at high temperature due to fewer dislocations to nucleation and slip with the reduction of high-stress region. Regardless of a significant increase in scratching velocity, there is little difference in the wear volume, indicating that the AlCoCrFeNi HEA still maintains excellent wear resistance even under extremely high scratching velocity. The stacking fault tetrahedron is generated in the AlCoCrFeNi HEA under the large scratching depths of 1.5 nm and 2.0 nm, implying that the wear resistance of AlCoCrFeNi HEA would be improved after the nanoscratching with a relatively large scratching depth. These findings are highly significant for expanding the application potential of AlCoCrFeNi HEA under extreme conditions and provide profound insights into the tribological behavior of the HEA.