Tribological behaviour of ultra-high molecular weight polyethylene (UHMWPE) pins sliding against thermal oxidation (TO)-treated Ti6A14V alloy discs with different levels of average surface roughness was investigated under water lubrication conditions. When rubbing against a smooth counterface (R(a) < 0.030-0.035 μm), UHMWPE was found to be worn predominantly via a micro-fatigue mechanism. To advance the scientific understanding of the microscopic wear mechanisms of UHMWPE, a technique involving permanganic etching coupled with high resolution SEM analyses of wear surfaces and cross-sections was adopted to yield new insight into the micro-fatigue mechanisms. It was found that stress-induced preferential orientation of the crystalline lamellae in the UHMWPE led to the origin of ripples containing micro-cracks at their valleys. The cyclic loading promoted lateral propagation and inter-connection of these micro-cracks, thus giving rise to eventual spallation of the surface material as wear debris. Based on the experimental results, a micro-fatigue wear mode is proposed. (C) 2000 Elsevier Science S.A. All rights reserved.
Bibliographical noteFunding Information:
The project was supported by the European Commission under IC15-CT96-0705. One of the authors (W. Shi) acknowledges the financial support of an Overseas Research Studentship (ORS) from the Committee of Vice-Chancellors and Principals (CVCP). In addition, the authors would like to thank Dr R.H. Olley at the J.J. Thomson Physical Laboratory (Reading, UK) for his help in providing technical information on etching UHMWPE.
- Wear mechanism
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering