Preparation and microstructure evolution of nanocomposite powder copper

The paper is aimed at preparing the nanocrystalline Cu-Al2O3 and Cu-MgO powders with 1-10 vol.% of the dispersoid by a combination of mechanical milling and phase precursor transformations. The secondary particles were prepared in situ within CuO powder. The nanometric Cu matrix was obtained by different reduction methods of the CuO precursor. The influence of dispersoid quantity and different technological parameters on the Cu microstructure was estimated. The study compares the microstructural evolution of Cu-3 vol.% MgO and Cu-3 vol.% Al2O3 composites. The effects of both oxides on the preservation of the initial powder nanostructure after consolidation and the thermal structural stability, as well as the tensile properties, are analysed. The results indicate that an alumina dispersoid is more suitable for nanostructure stabilisation of a Cu matrix compared to an MgO one, due to good coherency at the Cu/Al2O3interface.