Studies of Deformation at Sliding Wear Tracks in Iron.

Determinations of strains have been made on the surface and subsurface on specimens of high purity iron after different amounts of sliding wear have taken place. The method involved the measurement of loss of intensity (contrast) of particular electron channeling lines obtained from small selected areas near the wear track. Through the use of a calibration specimen deformed plastically to a range of strain values, the channeling line contrast loss was related to plastic strain. Strain maps lateral to the wear track and below the original surface were obtained for different total sliding distances by removing controlled thicknesses of iron using electropolishing. In all cases the maximum strain was found at the track center location at the surface and the strains decreased steadily with depth below the track. At 50 g load the strains vanished at about 40 micrometer depth. Significant strains were found to exist outside the wear track boundaries. The results are compared with other studies previously reported.