Abstract
Nanocrystalline (nc) Cu powders with Al₂O₃ dispersoid (1–5 vol.% Al₂O₃) were prepared by combination of phase transformations with intensive milling and the following consolidation by pressing, sintering and hot extrusion. The electrical properties of the composites were analysed in relation to their microstructure and strength. The main contribution to the electrical resistivity was attributed to the grain/crystallite size of Cu matrix. The fraction of Fe impurities dissolved within the Cu matrix and the amount of Al₂O₃ particles in the Cu matrix affected the electrical resistivity remarkably. The optimal combination of electrical and strength properties can be achieved by cut-down of Al₂O₃ content and by optimization of dispersoid distribution in the matrix.

Key words
nanocrystalline Cu-Al₂O₃ alloys, dispersion strengthening, electrical properties, thermal stability

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