THE MECHANICAL AND TRIBOLOGICAL BEHAVIOR OF CU-NB IN-SITU COMPOSITES

The mechanical and tribological properties of Cu-Nb in situ composites were studied. The composites were prepared by consumable arc melting of Cu and Nb electrodes, by casting, and by successive deformation of the cast ingot. Dry sliding friction and wear tests were performed in a pin-on-disk set-up, with the composite pin rubbing under atmospheric conditions against a hardened tool steel disk surface. The effect of Nb proportion on the tribological behavior of Cu-Nb composites was studied. It was found that the coefficient of friction decreased with increasing Nb proportion in the composite and that Cu-20vol.%Nb composite had the best wear resistance. The effect of prior deformation strain on the coefficient of friction and wear of Cu-15vol.%Nb composites was also investigated. The micromechanisms of wear were studied by scanning electron microscopy. It was concluded that cracking in the severely work hardened regions led to the generation of wear particles.