Comparative Evaluation of Untextured and Textured Surfaces for Wear, Wettability and Friction Characteristics

Reduction of frictional losses by changing the surface roughness in the form of surface textures has been reported as an effective method in reducing friction in the boundary regime of lubrication. Laser-based micro texturing has been mostly used to create these texture patterns and it is reported that it can reduce the frictional resistance by ~20-50%. However, the use of laser-based techniques for texture preparation led to residual thermal stress and micro cracks on the surfaces. Hence, the current study emphasizes using conventional micromachining on piston material (Al alloy Al4032) to overcome this limitation. Three variations of semi-hemispherical geometries were prepared on the surface of Al alloy with dimple depths of 15, 20 and 40 μm and dimple diameters of 90, 120 and 240 μm. Prepared textured surfaces with untextured surfaces are compared in terms of wear, wettability, and friction characteristics based on Stribeck curve behaviors. Results of this investigation demonstrated that the use of textures limited three-body abrasion wear, reduced wettability and extended the mixed regime of Stribeck curve for improved tribology behavior. Textured surfaces had effectively reduced mean coefficient of friction up to 12.6% for boundary regime of lubrication.