Probing the atomic-scale origins of anti-friction and wear-resisting in graphene-coated high-entropy alloys

Multilayer graphene (Gr) reinforced high-entropy alloys (HEAs) matrix composite shows promising prospects in anti-friction and wear-resisting. Nevertheless, a potential reinforcement mechanism at the atomic level urgently needs to be revealed. In the present work, through the molecular dynamics (MD) simulations, the friction and wear behavior of Gr coating reinforced HEA matrix composite on the basis of various normal loads and the number of Gr layers during scratching were analyzed. The coating effect of Gr was demonstrated to induce a substantial enhancement of anti-friction and wear resistance of HEAs matrix. Specifically, the narrowed distribution range of atomic forces combined with the counteraction between local pinning force and actuation force significantly weakened the friction. Meanwhile, the Gr coating-dependent inhibition of the pile-up effect was verified to substantially enhance the wear resistance. Especially, the increased Gr layers were validated to further reduce the friction and wear damage, attributing to the interlayer repulsion effect. Additionally, the experimentally detected reduction in scratch depth and inhibition of bulge behavior effectively supported our simulation findings. The analysis provides a theoretical insight to achieve superior surface performance and facilitates to prolong the service life of friction pairs.