A compact tribometer setup for in-situ investigation of tribological contacts using X-ray diffraction

Abstract

In triboexperiments, structural and chemical changes in a material that lead to wear and, subsequently, component failure, are usually investigated ex post, when wear patterns are already fully formed. Therefore, time-resolved in-situ analysis is crucial for an in-depth investigation of the evolution of these wear patterns to reveal the underlying mechanisms in the tribocontact that entail to material damage and failure.

This paper introduces a compact tribometer setup especially designed for operation inside a standard-sized diffractometer for both, laboratory and synchrotron applications. This setup enables the in-situ investigation of friction-induced wear mechanisms, such as material transfer, structural changes and surface layer formation using X-ray diffraction (XRD) analysis at specific points in time and space during the experiment without the necessity of sample transfer, which were complementarily compared to electron backscatter diffraction (EBSD) measurements.

First results obtained at the KMC-2 beamline at BESSY II are presented and compared to laboratory measurements of the same tribosystems. Steel on Ti experiments revealed a change in the preferential orientation of the Ti crystallites induced by a sliding steel pin immediately after a few cycles. In experiments with Al-on-Ti and brass-on-Cu configurations, a transfer of the softer pin material to the harder sample surface and the subsequent formation of a mixed oxide layer were observed.

The presented setup provides a versatile tool for the in-situ investigation of dynamic near-surface changes in tribosystems with a wide range of applications, including material transfer, surface layer formation, structural changes as well as the evolution of residual stresses.