FURTHER INVESTIGATION ON THE TRIBOLOGICAL BEHAVIOR OF CU-20-PERCENT NB INSITU COMPOSITE

Sliding friction and wear behavior of Cu-20 vol.% Nb in situ composite sliding against a tool steel disk was studied under dry ambient conditions. Studies were directed towards the understanding of the roles of the filament and the matrix materials during sliding. It was found that Nb filaments underwent reorientation, shearing and refinement. Irrespective of their prior orientation, Nb filaments close to the contact surface were oriented along the sliding direction. These processes resulted from friction-induced surface deformation and led to the strengthening of the subsurface layer of the composite. There was no separation of Nb filaments from Cu matrix observed in the sliding process. The effects of annealing, sliding speed and filament orientation on the friction and wear behavior of the composite were also investigated. The micromechanisms of wear were studied by scanning electron microscopy. Surface deformation, filament reorientation and refinement, and oxidation seemed to play important roles in the friction and wear processes.