Mechanical and tribological properties of Ti6Al4V alloy reinforced with Cu-coated multilayer graphene

In order to expand the application ranges of Ti6Al4V alloy in the rapidly developing aerospace industry, its mechanical and tribological properties need to be further improved. In this paper, multilayer graphene (MLG) and Cu-coated MLG are compounded into Ti6Al4V alloy respectively as the reinforcing and lubricating phase to prepare Ti6Al4V-MLG composites (TMC) and Ti6Al4V-Cu-coated MLG composites (TCMC). Mechanical and tribological experiments are carried out on TCMC in comparison with TMC and Ti6Al4V alloy. The results show that after adding Cu-coated MLG, the content of hard phase TiC produced by the interface reaction increases, and Ti2Cu phase is also introduced, thus Ti6Al4V-1.0 wt% Cu-coated MLG (TCMC2) obtains the highest microhardness, density and compressive strength. Meanwhile, TCMC2 exhibits relatively excellent friction and wear behaviors within wide ranges of applied loads and temperatures, which is mainly because of the formation of a Cu-coated MLG-rich lubricating film on the friction surface. In addition, owing to the good wettability of Cu and Ti, the lubricating film can be tightly combined with the subsurface material and keep working longer.