Dry sliding wear and microstructural behavior of centrifugally cast Al6061 - Al₂O₃ functionally graded composite

In this emphasized experimental learning, the dry sliding wear performance of Aluminium (Al) 6061 alloy strengthened with 10 wt% Alumina (Al₂O₃) Functionally Graded Composite (FGC) was manufactured through Horizontal Centrifugal Casting (HCC) technique. The Vicker’s microhardness examination confirmed a maximum hardness of 108 HV in the Al₂O₃ particle rich region, which is 76% higher than the hardness of the Al₂O₃ particle depleted region. The density different, and the centrifugal force is the root for the higher hardness in the outer periphery. The microstructural scrutiny certified the gradient dissemination of Al₂O₃ oxide particles from the exterior to the interior boundary. Taguchi’s methodology was used to optimize the wear experiment control variables such as applied load on the pin, sliding velocity with counter disc, and sliding distance over the disc. The wear experiment executed through the pin on disc tribometer showed the extreme lower Specific Wear Rate (SWR) in the Al₂O₃ particle rich region. Analysis of Variance (ANOVA) confirmed the higher contribution of applied load on the SWR, which is 74.91%. Moreover, the rise in applied load enlarged the SWR in the Al₂O₃ particle rich region owing to the rise in interaction pressure among the pin and the counter disc. The Energy-Dispersive Spectroscopy (EDS) examination confirmed the establishment of a tribolayer on the sliding surface, which protects the sliding surfaces from wear. The Hi-Resolution Scanning Electron Microscope (HRSEM) examination of the worn exterior confirmed the creation of an oxide layer and severe damage in extreme load situations.