Microstructure and magnetic properties of Cu90−xCo10Nix–7.5% SmCo5 composite alloys prepared by mechanical alloying and hot pressing

Nanocrystalline composites of CuCoNi (x = 0, 10, 20 wt-%) alloys reinforced with 7.5 wt-% of intermetallic SmCo particles were prepared by several processing steps. The production of these alloys started with the synthesis of CuCoNi powder alloys by mechanical alloying of pure Cu, Co and Ni in a planetary mill for 30 h at 250 rev min. As a second step, intermetallic SmCo particles were added, and additional milling was performed for 10 h. The resulting powders of both milling processes were characterised by means of an X-ray diffraction method, a scanning electron microscopy and an electron probe microanalysis. As a final fabrication step, CuCoNi–7.5% SmCo alloy powders were consolidated by hot pressing under 88 MPa for 75 min at 750°C in an argon atmosphere. The resulting compacts are reinforced by the precipitation of Co(Ni) during consolidation, and the presence of second-phase particles of oxides and intermetallic SmCo.The authors wholeheartedly thank CONICYT of Chile for the financial support granted through FONDECYT Project 1130831 and Comisión de Ciencia y Tecnología (CICYT) of Spain under Grant number MAT2012–39124.Peer Reviewe