Sliding wear behavior of deformation-processed Cu-15vol.%Cr in situ composites

Abstract

A deformation-processed Cu-15vol.%Cr in situ composite was made by consumable arc melting and casting followed by extensive deformation. A superior combination of mechanical strength and electrical/thermal conductivity was achieved with the composite since Cr filaments existed in the nearly pure copper matrix. The effects of sliding speed and normal pressure on sliding wear behavior and microstructure of the composite were investigated, with a composite pin rubbing against a hardened AISI 52100 steel disk on a pin-on-disk wear tester. In the studied range of normal pressure and sliding speed, the wear rate increased with increased normal pressure, whereas the wear rate decreased with increased sliding speed. Sliding-induced subsurface deformation occurred not only in the sliding direction but also in the lateral directions perpendicular to the sliding direction. This lateral flow produced a twisting of the Cr filaments. The complex deformation mode was revealed clearly by the morphological change of the ribbon-like filaments. Both constituents of the composite were cooperatively deformed. The thickness of deformed subsurface layer increased with increasing normal pressure and sliding speed. Scanning electron micrographs showed plastic deformation flow on the wear surface.