Laser Surface Texturing of Eutectic Al-Si Alloy

Abstract

Relative movement between piston and cylinder of an IC engine contributes to more than 60% of the friction experienced by the engine - in turn contributing to the wear of the piston and hence loss in its operational performance and efficiency. It is pertinent to explore technological solutions to overcome this situation. Texturing of surfaces appears to be an useful technique to enhance the tribological performance of the piston and cylinder assembly and information about the same are available in published literature. Laser surface texturing of a typical piston material such as an eutectic Al-Si alloy employing high power CO2-CW laser, firstly to examine the magnitudes of optimum laser processing conditions to realize surfaces which can retain oil and secondly to carry out characteristic analysis of the surface quality of the test material subjected to laser texturing, constitute the main thrust of this work. Measurements and analysis of the areal roughness parameters on the laser textured surfaces of the samples on a con-focal microscope reveal their capacity for enhanced oil retention, in turn ensuring reduced chances of scuffing of the sliding surfaces in comparison with non-textured samples, examined under similar test conditions.

Impact of surface texturing on the tribological behaviour of aluminium-silicon (Al-Si/Al2O3) advanced composite under dry and lubricating conditions

“…If the counter-surface contact width was bigger than the feature dimension, it was shown that textured features might reduce the average coefficient of friction by as much as 37% through a lubricant reservoir mechanism. A typical piston material, such as a eutectic Al-Si alloy, was laser surface texturized using a high power CO2-CW laser, according to Nandakumar et al [27]. The tests were performed in two ways: first, to determine the ideal laser processing parameters to produce surfaces that can hold oil; and second, to conduct a typical study of the test material's surface quality after laser texturing.…”