An investigation into the tribological behaviour of cutting fluid additives on Ti‐6Al‐4V alloy

Abstract

The performance of polymer-based and phosphorus-based cutting fluid additives have been shown to depend on the machining conditions employed. This study investigated the tribological behaviour behind the previously reported machining performance of polymer-based and phosphorus-based additives on Ti-6Al-4V using ball-on-disc tests. The coefficient of friction (COF) was evaluated using ball-on-disc tests, surface characterisation was performed on the Ti-6Al-4V and steel ball counterfaces to investigate the wear and friction reduction mechanisms. The tribological performance of the phosphorus-based additive was observed to be influenced by the applied load and temperature. The activation of this additive resulted in a reduction in COF at elevated temperatures. However, the activation temperature was observed to be influenced by the applied load. The COF associated with the polymer-based additive was noted to increase as the temperature increased, regardless of the applied load. The formation of tribolayers from the additives was related to the COF behaviour as well as the surface damage on Ti-6Al-4V and lower material transfer to the steel counterfaces.

The Influence of Phosphate-Ester-Based Additives on Metal Cutting Fluid Behavior during the Machining of Titanium Alloy

“…Although both of the additives were environmentally benign, this highlighted the difficulty in replacing EP additives during machining within the boundary lubrication conditions. Further work revealed that the performance of the phosphorusbased additive was a result of the introduction of phosphorus into the tribolayer within a critical temperature range and its lubrication failure temperature, and the activation temperature of phosphorus-based additive was influenced by the applied load [25,26]. However, additional work with polymeric ester additives revealed that the performance of each polymeric ester was also dependent on the drilling condition employed [27].…”