Leaf Coppin 325 Mechanical Properties of Tribologically Modified Nanolayers zy D. Shakhvorostov zyxwv IAVF Antriebstechnik AG, Karlsruhe, Germany H. Pinto and A. Pyzalla TU Wien, Institut fur Werkstoffkunde und Materialprufung, Vienna, Austria S. Enders Max-Planck Institut fur Metallphysik, Stuttgart, Germany K. Pohlmann and M. Scherge IAVF Antriebstechnik AG, Karlsruhe, Germany zyx Abstract Wear in modern mechanical systems is characterised by ultra-low wear rates in the range ojafezu nanometres per hour. The surfaces of the materials involved, as well as their volumes, experience modifications as regards morphology, cystalline arrange- ment, and chemical bonds. The depth of the tribological interactions under given conditions extends to a micrometre or less. To probe these thin modified zones, synchro- tron-based X-ray diffraction and nano-indentation mere applied. The specimens were taken from tribometer experiments employing the radionuclide technique to measure ultra-lozo wear rates. To obtain different degrees of tribological interaction, various loads and sliding velocities were applied. The specimens ivere subdivided according to the total power dissipated during the tribometer experiment. Keywords tribological modification, mechanical properties, modified nanolayers, ultra-low iuear, X-ray difraction, nano-indentation INTRODUCTION Owing to mechanical intermixing during tribological stressing, the near-surface volumes of sliding partners gradually become modified as regards morphology, crystalline structure, and chemical composition. Necessary preconditions to ini- tiate mechanical intermixing include sufficiently high values of normal force Fn and/or sliding velocity v. The response of the system is expressed by the coefficient of friction zyxwv p. The total dissipated power can be written as: Tribotest journal 214, J14ne 2005. (11) 325 lSSN 1354-4063 $50.00 (2633/0605)