Preparation of copper–molybdenum nanocrystalline pseudoalloys using a combination of mechanical activation and spark plasma sintering techniques

Abstract

Nanostructured powders of pseudoalloys of immiscible Cu and Mo metals are prepared by highenergy ball milling (HEBM). Mechanical alloying in an Activator-2S planetary ball mill for 60 min provides a uniform distribution of refractory Mo particles in a moldable Cu matrix on submicron and nanoscopic levels. Nanostructured Cu–Mo powders are consolidated by spark plasma sintering (SPS) in a temperature range of 700–950°C at a pressure of 50 MPa for 10 min. The effect of preparation conditions on the microstructure, crystal structure, and properties (density, hardness, electric resistivity) of the nanostructured Cu–Mo pseudoalloys is studied. It is shown that a combination of HEBM and SPS provides the formation of a high-density (97%) nanostructured consolidated Cu–Mo composite with a hardness of 3.68–3.88 GPa and an electric resistivity of 6.1–6.2 μΩ cm; these parameters made the composite promising for use as an electric-contact material.