Investigation of rare earth particulate on tribological and mechanical properties of Al-6061 alloy composites for aerospace application

Current research work emphasis on the development of rare earth particulate (REP) reinforced hybrid aluminium matrix composites processed by stir casting route. The weight percentage of CeO2 as rare-earth particulate varied from 0.5 wt% to 2.5 wt% and SiC /Al2O3 varied from 2.5 wt% to 7.5 wt%. The presence of rare earth particulate helps in grain refinement of the matrix with well defined grain boundaries is seen via Electron Backscatter Diffraction (EBSD) analysis. The Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) examination were used to characterize the prepared samples of Al-6061 hybrid composites. Porosity analysis, Vickers microhardness, tensile behavior, flexural strength and impact strength of the hybrid composites improved significantly with the addition of rare earth particulate. The flexural strength of the Al-6061 hybrid composites is found to be increased upto 44.76% by increased weight percentage of rare earth oxide phase. The optimum quantity of CeO2 as RE that favours the better tribological and mechanical characteristics of aluminium hybrid composites was found to be 2.5 wt%. The results of wear tests showed an improvement of wear rate around 87.28% when compared to Al-6061 alloy with the addition of 2.5 wt% of CeO2. Finally, the worn out surface of the hybrid composites is examined with the help of scanning electron microscope to understand the wear mechanism of the composites for aerospace application. (C) 2019 The Authors. Published by Elsevier B.V.