DEFORMATION STRUCTURES INDUCED BY SLIDING CONTACT

The deformed microstructure generated by the sliding contact of a low carbon 316 stainless steel against a ceramic counterface has been investigated by transmission electron microscopy. Deformation occurred by twinning followed by intense shear banding. Once formed, the shear bands were shown to accommodate a large strain by crystallographic slip. The structure and the texture observed indicated that the deformation could be best described by simple shear (torsion) which led to a saturation flow stress. Contact was shown to be plastic over the load range 2-55 N (pin)-1. Wear debris was apparently created within freshly formed shear bands at the outermost surface, coinciding with the maximum strain. The implications of the microstructural evolution are discussed in terms of wear theories and behaviour of metals at high strains.