Effect of In-situ Processing Parameters on the Mechanical and Tribological Properties of Self-Lubricating Hybrid Aluminum Nanocomposites

In the present investigation, aluminum/TiB2/Al2O3 metal matrix composite was fabricated using the liquid metallurgy route. The transmission electron microscopy study was conducted in order to investigate the microstructure of the in-situ processed composites. X-ray diffraction analysis of the composite was performed to investigate the various phases present in the composite. Dry sliding tests were conducted using pin-on-disk tribometer in order to understand the self-lubricating behavior of developed composite. The microstructural characteristics revealed formation of in-situ phases and uniform dispersion of the reinforcement phases throughout the composite. The developed hybrid self-lubricating nanocomposites showed superior mechanical and tribological properties. The superior tribological properties of hybrid composite are attributed to the formation and synergetic effect of TiB2 and Al2O3 particles in the composites. The Al2O3 hard ceramic particles act as the obstacles to the movement of dislocation and thus enhance the mechanical properties. The oxidation of TiB2 on the surface forms H3BO3 and TiO2 tribolayer resulting in superior tribological properties.