Influence of subsurface plastic deformation on the running-in behavior of a hypoeutectic AlSi alloy

The present publication elaborates on the influence of the initial microstructure preset by machining on the friction and wear behavior of a hypoeutectic AlSi9Cu3 alloy. During running-in the subsurface microstructure of tribological contacts is subjected to shear followed by plastic deformation. Aluminum disks were tested with a steel pin on a pin-on-disk tribometer with focus on running-in and sensitivity phenomena. The systems were operated in the ultra-low wear regime. Wear was measured continuously using Radionuclide Technique. The microstructure of the samples was characterized by nanoindentation, x-ray photoelectron spectroscopy and focused ion beam microscopy. The visualization of subsurface shear by markers in the disks showed a significant correlation of subsurface deformation and wear. With the experiments the relationship between machining and tribological behavior was analyzed and ways to optimize tribological systems were shown.