Berlin 2015 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 51: Mechanical properties II

MM 51.4: Talk

Thursday, March 19, 2015, 11:00–11:15, TC 010

Roughness and Microstructure Development during Nanotribology in Austenite — •Steffen Brinckmann, Caroline Fink, and Gerhard Dehm — Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

Materials wear is the collective contact on a number of hierarchical length scales. The macroscopic surface has microscopic surface roughness which itself has an almost atomistic surface roughness superimposed. We study wear at the microscopic lengthscale by using a single hard asperity and study the deformation of the flat Austenite steel. Single stroke experiments reveal that the plasticity and roughness are determined by the local grain orientation. Moreover, the symmetric scratch loading can lead to unsymmetrical slip patterns, when comparing both sides of the scratch. We find that analytical equations based on the Hertz solution and the Hardness equation predict the elastic and plastic scratch depth for multiple orders of normal force, although both equations were developed for the static indentation loading and not the present dynamic scratch loading. Finally, we will discuss the formation of cracks and surface roughness in the scratch tracks. We close with a discussion on the addition of the plasticity induced surface roughness to the hierarchical length scales in tribology.