Wear during lubrication is a complex process that depends on many factors, including the characteristics of the lubricant, the properties of the contacting surfaces and the operating conditions. In the case of using quasi-crystalline abrasive Al62Cu25.5Fe12.5 in the processing of soft metals, the wear mechanism acquires specific features.
Quasicrystals, having a unique atomic structure, are characterized by high hardness and low adhesion. This property helps to reduce the coefficient of friction and reduce wear during lubrication. However, abrasive particles of Al62Cu25.5Fe12.5 can penetrate into the soft surface of the metal, causing micro-scratches and plastic deformation.
Lubricant plays a key role in minimizing wear. It creates a protective film between the abrasive and the surface being machined, reducing direct contact and decreasing friction. Lubricant efficiency depends on its viscosity, adhesion to the metal surface, and ability to withstand high loads. Experimental studies have shown that the optimal choice of lubricant and machining parameters can significantly reduce soft metal wear when using quasi-crystalline abrasive Al62Cu25.5Fe12.5. Quasi-crystalline abrasives are subject to intense wear, while traditional abrasives easily damage and scratch soft metals. Using quasi-crystals to polish soft metals allows for a smooth surface with minimal material removal. The predominant wear mechanism is smearing, characterized by a decrease in the size of the depressions relative to the depth of surface treatment.
The abrasive properties of quasi-crystalline Al62Cu25.5Fe12.5 material in polishing aluminum and austenitic stainless steel are investigated and compared with traditional hard abrasives such as diamond, aluminum oxide, and silica. The quasi-crystalline abrasive exhibits a predominant smearing wear mechanism, which is different from other abrasives, as demonstrated by the decrease in the size of the depressions relative to the processing depth. Polishing with quasi-crystals, which provides a flat surface with low material removal, may open up new applications where low wear and precise surface finishing are required.
Quasicrystals have unique surface properties such as low friction coefficient, low surface energy and high corrosion resistance. Their coefficient of friction has been measured to be between 0.05 and 0.2, which is significantly lower than that of copper, aluminum and low-carbon steel. The low friction is due to the low density of electron states at the Fermi level. The Vickers hardness is about 6.5–11 GPa, which is comparable to that of quartz. The combination of these properties makes them suitable for non-stick coatings. Low-friction abrasives typically cause lubrication-type wear when polished, providing a smooth surface without significant material removal.
Therefore, quasicrystals may be useful in areas where low wear resistance and fine surface finish are required. They are already used as solid lubricant additives in motor oil.
This paper investigates the abrasive polishing effect of Al–Cu–Fe particles on soft metals in comparison with traditional hard abrasives.
Author: Yunjun Chen,Jianbing Qiang, Chuan Dong
Institute: Key Laboratory of Material Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China