Tensile properties of carbon nanotube reinforced aluminum nanocomposite fabricated by plasma spray forming

Uniaxial tensile tests were performed on plasma spray formed (PSF) Al-Si alloy reinforced with multi-walled carbon nanotubes (MWCNTs). The addition of CNTs leads to 78% increase in the elastic modulus of the composite. There was a marginal increase in the tensile strength of CNT reinforced composite with degradation in strain to failure by 46%. The computed critical pullout length of CNTs ranges from 2.1 to 19.7 mu m which is higher than the experimental length of CNT, leading to relatively poor load transfer and low tensile strength of PSF nanocomposites. Fracture surface validates that tensile fracture is governed strongly by the constitutive hierarchical microstructure of the plasma sprayed Al-CNT nanocomposite. The fracture path in Al-CNT nanocomposite occurs in Al-Si matrix adjacent to SiC layer on CNT surface. (C) 2009 Elsevier Ltd. All rights reserved.