Fabrication of carbon nanotube(MWCNT) reinforced aluminum alloy matrix composite

Maluti-walled carbon nanotube reinforced Al-12wt%Si eutectic aluminum alloy matrix composite was fabricated by powder metallurgy and consolidated by SPS method and the microstructures were examined. The amounts of carbon nanotubes in powder milled by ball milling analyzed by chemical analysis were nealy equal to those added. The Vicker's hardness of the powders milled and the composites increased with increasing the amount of carbon nanotubes up to about 5wt%. The density of composites measured by Archimedes method was more than 95% up to the amount of carbon nanotubes of 5wt%. The Young's modulus of the composites evaluated by a ratio of longitudinal ultrasonic wave velocity to transverse one also increased with increasing the amount of carbon nanotubes. The elastic moduli of composites estimated using the rule of mixture were nearly equal to the experimental values. The strengths of the composite containing the amount of carbon nanotubes of 2 and 5wt% evaluated on the basis of the linear relationship between hardness and tensile strength were about 470-534 MPa and 690 MPa, respectively, while for the unreinforced materials was about 200 MPa. The estimated strength drastically increased due to the content of carbon nanotubes. The observation of TEM revealed that the carbon nanotubes were dispersed in the matrix.