Mechanochemical assisted synthesis of Cu(Mo)/Al2O3 nanocomposite

In the present study, Cu(Mo)/30Vol.% α-Al2O3 nanocomposite was successfully synthesized by a displacement reaction between Al and MoO3 in ball milling of initial Cu, MoO3 and Al powders. The evaluation of powders was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential thermal analysis (DTA) and measurements of vial temperature. The results showed that mechanochemical reaction between MoO3 and Al took place at the early stage of milling in combustion mode and led to increase of the vial temperature and formation of Al2O3 reinforcements. By increasing the milling time, Mo dissolves in copper matrix. Finally after 60 h of milling, the formed nanocomposite contains nanostructured supersaturated Cu(Mo) solid solution matrix, with a homogenous distribution of nanosized Al2O3 and Mo reinforcements. Annealing of milled powders at 700 °C for 30 min, showed no significant increase in crystallite size of matrix, however partial transformation of α-Al2O3 into different polymorphic γ-Al2O3 was observed. Microhardness of this nanocomposite was found to be about 307 HV which is higher than pure Cu.