Enhancing Tribological Properties of Metallic Sliding Surfaces through Micro Multi-texturing Techniques

Date
2019-07-10
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Abstract
Friction reduction is important for minimizing energy loss and improving the life of sliding components. Surface texturing is considered an effective way to control the wear and friction on these components. In this research, textured surfaces were created on aluminium workpieces using the tilted micro end milling technique. A flat end mill was used to generate asymmetric dimples. A different series of symmetric dimpled surfaces were also machined using a single crystal diamond cutter. Cutting forces were modelled and compared with the experimental results. On the symmetric dimpled surface, a multi-scale texture process was carried out on the dimples to create a smaller scale roughness through a High-Velocity Abrasive Machining process. A reciprocating tribometer, based on a piezoelectric table dynamometer and a hemispherical ruby counter surface, was used to evaluate friction coefficients under both dry and lubricated sliding conditions. Asymmetric dimples exhibited directional friction effects. For multi-scale textured surfaces, it has been observed a greater reduction in the friction coefficient under lubricated conditions when compared with symmetrical dimples. To gain insight into the mechanism of friction reduction for these surfaces, a series of 2D simulations were performed. These simulations showed that the mechanism of friction reduction is attributed to the ability of dimples to increase the pressure of the lubricant in the contact region resulting from the fluid flow between the sliding surfaces. Moreover, a substantial decrease in the depth of the dimples on worn surfaces was observed, suggesting that entrapment of wear particles within the surface texture features may also influence the measured friction coefficient. Analysis of the wear track depth showed that surface texturing also has a beneficial influence on the calculated Archard wear coefficient.
Description
Keywords
Tribology, Texturing surfaces, Micro-machining
Citation
Reséndiz-Pérez, J. D. J. (2019). Enhancing Tribological Properties of Metallic Sliding Surfaces through Micro Multi-texturing Techniques (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.