Friction and wear of nanostructured metals created by large strain extrusion machining

Tribological behavior of nanocrystalline oxygen-free high conductivity (OFHC) copper and commercially pure titanium produced by large strain extrusion machining (LSEM) is compared with the coarse grained counterparts. Friction and wear of these materials have been determined using a pin-on-disk tribometer, sliding against AISI 52100 steel pins. Although friction coefficients are very similar, microstructure refinement reduces wear factors for these conditions. Wear mechanisms are discussed from optical microscopy and SEM observation of wear tracks, wear debris morphology and transfer tribolayers.