Mechanical alloying of Cu–Mo powder mixtures and thermodynamic study of solubility

A set of Cu-based powder mixtures containing up to 8 at.% Mo has been processed through mechanical alloying for a range of milling times up to 75 h. The milling operation was carried out using two types of milling media, stainless steel and tungsten carbide balls, keeping a constant powder to balls weight ratio of 10:1. The alloyed powders obtained were characterised by X-ray diffraction and scanning electron microscopy in order to determine the mean crystallite size and particles morphology after milling, respectively. The crystallite size produced after milling was quantitatively determined based on both, the Scherrer and Williamson–Hall methods. An estimate of the increased solubility of Mo in Cu, produced by the microstructural refinement during milling, was carried out through a thermodynamical analysis based on the influence of crystallite size reduction on chemical potentials.