Dry Sliding Tribological Performance of LM6-Si₃N₄ Nanocomposites

In the current study tribological behaviour of LM6 aluminium alloy reinforced with varying content (0 – 2 wt.%) of silicon nitride (Si3N4) nanoparticles is analyzed. The nanocomposites are fabricated through stir casting process with ultrasonic-assistance and characterised through optical microscopy (OM), FESEM and EDAX. Microstructural analysis indicated a 78.37% reduction in average grain size. Vicker’s microhardness test is conducted on the specimens. Result of microhardness test reveals around 35% increase in microhardness values with the integration of 2 wt.% nano Si3N4 particles, compared to monolithic alloy. Dry sliding friction and wear experiments are conducted through a pin-on-disc tribotester under varying sliding velocities (0.1 – 0.4 m/s) and loads (10 – 40 N). Results of tribological experiments exhibit a noticeable depletion in wear rate with increasing nanoparticles content. Around 39% to 52% enhancement in wear resistance is observed in nanocomposites over base alloy under different experimental conditions. FESEM and EDAX analysis of worn-out surfaces confirms the process of oxidative wear mechanism and protective tribolayer formation, resulting to enhanced tribological behaviour for nanocomposites.