Fabrication and properties of silver-matrix composites reinforced by carbon nanotubes

Composites of carbon nanotubes in a silver matrix have been fabricated by a powder metallurgy method. The effects of different nanotube contents on the relative density, hardness, bend strength and electrical resistivity of the composites were investigated. The results showed that the addition to the silver matrix of 8% by volume of carbon nanotubes caused increases in the Vickers hardness and the bend strength of about 27% and 9%, respectively. The nanotubes contributed less to the bend strength than to the hardness. The electrical resistivity of the composites increased slightly with increasing nanotube volume fraction when the volume content of the nanotubes was less than 10 vol.%. However, as the volume content increased from 10% to 25%, the resistivity experienced a sharp increase. Possible mechanisms are discussed in detail in the paper.