Production of copper-niobium carbide nanocomposite powders via mechanical alloying

Nanocrystalline niobium carbide was synthesed in situ in a copper matrix during high-energy milling of elemental powders. Three powder batches were produced with nominal compositions of 5, 10 and 20 vol.% NbC. Characterisation by X-ray diffraction and scanning electron microscopy indicates that early during the milling process a carbide dispersion is formed within a nanostructured copper matrix. After annealing at 873 K, the carbide structure and particle size are maintained, reflecting the ability of the microstructure to resist to coarsening. The hardness levels attained are more than twice those of nanostructured copper.