Abstract
In this study, the effect of friction layer thickness and subsurface nano-hardness of wear track on tribological behavior of gamma-TiAl matrix composites is investigated. The results of dry sliding tribolocial tests of gamma-TiAl matrix composites with 0-2.25 wt.% multilayer graphene (MLG) (0.25 wt.% in tolerance) under different applied loads are reported. The testing results show that the optimized addition amount of MLG is 1.75 wt.% at 12 N (friction layer thickness 3.23 A mu m, subsurface nano-hardness of wear track 9.03 GPa). It can be found that a continuous and thick friction layer is formed in gamma-TiAl-1.75 wt.% MLG at 12 N, resulting in a lower friction coefficient of 0.31 and wear rate of 2.09 x 10(-5) mm(3) N-1 m(-1). During dry sliding process, the high subsurface nano-hardness of wear track leads to the increase in resisting plastic deformation capacity and reduces the material loss. Meanwhile, the thick friction layer contains MLG with high tensile strength which is easily sheared off. Hence, gamma-TiAl matrix composites show excellent tribological performance of a friction-reducing and an increase in wear resistance. The investigation shows that gamma-TiAl-1.75 wt.% MLG, due to its excellent tribological behavior at 12 N, can be chosen as a promising structural material for minimizing friction- and wear-related mechanical failures in sliding mechanical components.