The comparative research on tribological behavior of carbon-doped CoCrFeNiV high entropy alloys in air and vacuum environments

In the field of aviation and aerospace engineering, the application of high-entropy alloys (HEAs) is inevitably needs to withstand the damage of both wear and adhesion in vacuum. Herein, the vacuum tribological behavior of a high performance Co21Cr21Fe21Ni21V14.5C1.5 HEAs (C12) were investigated. In this study, the hardness and compressive strength, significantly improved for Co21Cr21Fe21Ni21V14.5C1.5 (1200 °C, C12) HEA compared to the CoCrFeNiV (C0) base alloy. The focus was put on the effect of C element and sintering temperature at 1000℃ and1200 ℃ (C10 and C12) on the microstructure and vacuum tribological mechanisms of the alloy. It was found that the friction coefficient of the C12 alloy under air can be minimized to lower than 0.37. The wear rate of C12 alloy ((1.31-2.67)×10−4mm3/Nm) is 2-4 times lower than that of C10 alloy (2.91-8.31)×10−4 mm3/Nm). The wear-resistance of Co21Cr21Fe21Ni21V14.5C1.5 alloy at sinter temperature 1200 °C (C12) is significantly higher than that of alloy sinter temperature at 1000 °C (C10). Therefore, C12 alloy exhibited optimal vacuum tribological properties. This work provides helpful guidance for material design and wear resistance in the field of space tribology.