Processing, Microstructure and Properties of Micro and Nano Alumina Reinforced Aluminium Composites

Abstract

The evolution of microstructure by varying the particle size of reinforcement in the matrix by employing powder metallurgy has been demonstrated here in Al–Al2O3 system. An emphasis has been laid on varying the reinforcement particle size and evaluating the microstructural morphologies and their implications on mechanical performance of the composites. Nano composites of 8 volume % alumina (average size < 50 nm) reinforced in aluminium matrix were fabricated by powder metallurgy route. Another set of specimens having same composition (average size ~ 10 ìm) had been fabricated to compare the physical as well as mechanical attributes of the microcomposites as well as the nanocomposites. These micro- and nano-composites have been characterized using X-ray diffraction, scanning electron microscopy and followed by density, microhardness, compressive strength, wear resistance and corrosion resistance measurements. The alumina nanoparticles revealed an interface showing appreciable physical intimacy with the aluminium matrix compared to that of the alumina microparticles. By employing the powder metallurgy route the agglomeration is reduced and no new phases were formed as the temperatue is very low.