Fabrication and properties of Cu matrix composites reinforced by tungsten-coated carbon nanotubes

Multi-walled carbon nanotubes (CNTs) were coated with tungsten layers using a carbonyl thermal decomposition process. The tungsten-coated carbon nanotubes (W-CNTs) and electrolytic copper powders were used as starting materials to fabricated W-CNT/Cu composites by mechanical milling and spark plasma sintering (SPS). The morphologies and microstructures of the mixed powders and the sintered composite bulks were characterized by field-emission scanning electron microscopy (SEM), and the phase analysis of the sintered composite bulks was carried out by X-ray diffraction (XRD). The influences of W-CNT content and sintering temperature on the relative density, tensile strength, elongation and electrical conductivity of the W-CNT/Cu composites were investigated. The experimental results show that the 1% W-CNT added composites sintered at 850℃ have the maximum relative density, tensile strength and electrical conductivity. In comparison with the sintered pure Cu bulk, the tensile strength increases by 103.6% but the electrical conductivity decreases only by 15.9% for the W-CNT/Cu composites.