Tribological characterization of eco-designed aluminium hybrid metal matrix composites

In present experimental investigation, wear characteristics of Al 7075-T6/Eggshell/SiC/Al2O3 hybrid composites (Al 7075-T6 as base metal with eggshell particles wt. % 0.5, 1and 1.5, average particle size ~ 60 µm, SiC particles wt. % 1, 1.5 and 2, average particle size ~ 65 µm and Al2O3 particles wt. % 1.5, 2 and 2.5, average particle size ~90 µm) synthesized through electromagnetic stir casting route have been studied at various specimen temperatures under dry and lubricated test conditions. Wear investigations have been conducted on pin-on-disk rotary tribometer at a constant load of 20 N for a sliding speed of 2m/s and sliding distance of 2 km. Tribological attributes of synthesized composites have been evaluated as the function of reinforcements content and mechanical stirring time, as per the design of experiment according to Taguchi L9 orthogonal array. Experimental study has shown that at 30 ºC pin temperature under dry wear condition, among the developed hybrid composites, specimen S8 demonstrated a maximum relative decrease of 60% in wear loss while with lubrication the wear loss has been relatively decreased by 89% as compared to the base metal (specimen S0). At elevated pin temperature of 70 ºC under dry wear condition, the hybrid composite specimen S8 exhibited maximum relative reduction of 82% in wear loss whereas under lubricated condition the wear loss has been relatively reduced by 82% in comparison of their unreinforced counterpart (specimen S0). With exceedingly augmented tribological attributes, the current study strongly rationalizes high temperature wear resistant applications of synthesized aluminium hybrid composites with a total reinforcement weight percentage of 4.5% only (specimen S8).