TY - JOUR

T1 - Impacts of the substrate stiffness on the anti-wear performance of graphene

AU - Yao, Quanzhou

AU - Qi, Yizhou

AU - Zhang, Ji

AU - Zhang, Shuai

AU - Zhao, Pei

AU - Wang, Hongtao

AU - Feng, Xi Qiao

AU - Li, Qunyang

N1 - Funding Information: This work was supported by the National Natural Science Foundation of China (Grant Nos. 11772169, 11432008 and 11890671), National Basic Research Program of China (Grant No. 2015CB351903), the National Key Scientific Instruments and Equipment Development Project of China (61427901), and the State Key Laboratory of Tribology at Tsinghua University (Grant No. SKLT2019B02).

PY - 2019

Y1 - 2019

N2 - Owing to its excellent mechanical and tribological properties, graphene has been proposed to be a promising atomically-thin solid lubricant for engineering applications. However, as a typical two-dimensional (2D) material, graphene has an exceptionally high surface-to-volume ratio and is very susceptible to the surrounding environments. By performing nanoscale scratch tests on graphene deposited on four different substrates, we have shown that the anti-wear performance of graphene, characterized by the maximum load carrying capacity, is not an intrinsic material property. Instead, its value is significantly affected by the stiffness the substrates: Stiffer substrate typically results in a higher load carrying capacity. As revealed by finite element simulations, stiffer substrate can effectively share the normal load and reduce the in-plane stress of graphene by limiting graphene deformation, which enhances the overall load carrying capacity. In addition to the load sharing mechanism, the experimental results also suggest that the frictional shear stress during scratch tests may facilitate wear of graphene by lowering its equivalent strength. The deformation mechanism of graphene/substrate systems revealed in this work provides guidelines for optimizing the mechanical performance of 2D materials for a wide range of tribological applications.

AB - Owing to its excellent mechanical and tribological properties, graphene has been proposed to be a promising atomically-thin solid lubricant for engineering applications. However, as a typical two-dimensional (2D) material, graphene has an exceptionally high surface-to-volume ratio and is very susceptible to the surrounding environments. By performing nanoscale scratch tests on graphene deposited on four different substrates, we have shown that the anti-wear performance of graphene, characterized by the maximum load carrying capacity, is not an intrinsic material property. Instead, its value is significantly affected by the stiffness the substrates: Stiffer substrate typically results in a higher load carrying capacity. As revealed by finite element simulations, stiffer substrate can effectively share the normal load and reduce the in-plane stress of graphene by limiting graphene deformation, which enhances the overall load carrying capacity. In addition to the load sharing mechanism, the experimental results also suggest that the frictional shear stress during scratch tests may facilitate wear of graphene by lowering its equivalent strength. The deformation mechanism of graphene/substrate systems revealed in this work provides guidelines for optimizing the mechanical performance of 2D materials for a wide range of tribological applications.

UR - http://www.scopus.com/inward/record.url?scp=85069466515&partnerID=8YFLogxK

U2 - 10.1063/1.5095055

DO - 10.1063/1.5095055

M3 - Article

VL - 9

JO - AIP Advances

JF - AIP Advances

SN - 2158-3226

IS - 7

M1 - 075317

ER -