Evaluating the Correlations Between Surface Roughness and Dynamic Friction During Metal Forming

The influence of surface roughness on the dynamic friction behavior of AA5754-O aluminum was evaluated with single-pull friction experiments in three significantly different surface roughness conditions: polished to a 1.0 μm diamond finish, polished with 8 %, and polished with 16 % uniaxial plastic strain. The surfaces were examined before and after the friction tests with confocal microscopy. The changes observed in the dynamic friction coefficient between the polished and roughened surfaces imply that the influence of surface roughness on the friction may reach a steady state prior to 8 % plastic strain. The friction test also produced distinct changes in: the topographic images; the plots of both the probability density and the 2-point correlation function ensembles determined from the topographic data; and the numeric quantities calculated from the probability density and 2-point correlation data.