Effect of Temperature on Aluminum Alloy (Al4032) Using Textured Surface

The larger domain of surface texture geometry and other input variables related to engine operation, i.e., elevated temperature, has remained to be studied for finding suitable surface texture for real-time engine operations. In previous efforts to find suitable surface texture geometry and technique, the tribological performance of the piston material (Al4032) with dimples of varying diameters (90 to 240 μm) was evaluated under mixed and starved lubrication conditions in a pin-on-disk configuration. The disc was textured using a ball nose end mill cutter via conventional micromachining techniques. The area density and aspect ratio (depth to diameter) of the dimples were kept constant at 10% and 1/6, respectively. SAE 20W-40 oil was used as a lubricant with three separate drop volumes. The experiments were conducted in oscillating motion at temperatures of 50, 100 and 150°C. Conventional micromachining achieved improved dimensional precision and minimized thermal damage. Textured surfaces have shown reduced friction at elevated temperatures in both mixed and starved regimes of lubrication due to increased load-carrying capacity and reduced surface contact, respectively. Textured surfaces with a dimple diameter of 240 μm offered better storage for debris and wear particles, reduced surface contact and held a greater quantity of lubricant, resulting in better tribological characteristics compared to other textured and untextured surfaces.