Running-In of Systems Protected by Additive-Rich Oils

Recent research on mild wearing systems running under boundary lubrication conditions focus more and more on the role of the nano-crystalline layer present at the surface of the components in contact. This layer has a typical thickness of a few tenths of nano-meters up to a few microns depending on the operational conditions. The role of this layer with respect to wear is, however, still unclear as well as its mechanical behavior. In this study, a first step is made in incorporating this type of layer into a wear model. Using an elasto-plastic semi-analytical-method the effect of different material behaviors reported through out current literature for the nano-crystalline layer on wear is studied. From the results it can be concluded that the effect of this mechanically altered layer has an important influence on the wear of the system, especially during the initial phase of running.