Effect of sintering on thermally sprayed carbon nanotube reinforced aluminum nanocomposite

Reconsolidation of thermally spray formed (plasma and high velocity oxyfuel spraying) hypereutectic Al–Si nanocomposites with multiwalled carbon nanotube (MWCNT) reinforcement was carried out by inert atmosphere sintering for prolonged time periods. The sintering treatment resulted in the removal of porosity and residual stress, and increase in size and volume fraction of primary Si particles in the Al–Si matrix. The morphology of multiwalled carbon nanotubes in sintered nanocomposites remained unchanged after sintering. The interfacial ultrathin product layer of silicon carbide between MWCNT reinforcement and Al–Si matrix was unaltered. Microhardness and elastic modulus of the sintered nanocomposites were influenced by combined effect of multiple factors, i.e. reduction in porosity, residual stress removal and MWCNT distribution. Overall improvement of microhardness and elastic modulus of the sintered nanocomposites was observed. The experimentally measured elastic modulus values were compared with theoretically estimated values using micromechanics models.