Research on the Thickness of the Friction Layer of Ni3Al Matrix Composites with Graphene Nanoplatelets

Dry sliding tribological tests of Ni3Al matrix composites (NMCs) with/without graphene nanoplatelets (GNPs) under different working conditions are undertaken in this article. The results show that GNPs in NMCs make a major contribution to the formation of the friction layer, which is responsible for the reduction of the friction coefficient and improvement of wear resistance. In addition, with the increase in the sliding velocity and normal load, the friction coefficient decreases to a stable value and the wear rate increases to a stable value. This article also examines the possibility of describing the formation of the friction layer during the sliding process. The formation of the friction layer can be divided into two processes: the formation of the fine grain layer and the material loss of the surface layer. The strain rate intensity factor is used to describe the formation of the fine grain layer, and the functional relation of the material loss of the surface layer is obtained by the experimental data. As a result, a specific formula for calculating the thickness of the friction layer of NMCs with GNPs is found.