Microstructure and magnetic properties of Cu_90−xCo₁₀Ni_x–7.5% SmCo₅ composite alloys prepared by mechanical alloying and hot pressing

ABSTRACT

Nanocrystalline composites of Cu_90−xCo₁₀Ni_x (x = 0, 10, 20 wt-%) alloys reinforced with 7.5 wt-% of intermetallic SmCo₅ particles were prepared by several processing steps. The production of these alloys started with the synthesis of Cu_90−xCo₁₀Ni_x powder alloys by mechanical alloying of pure Cu, Co and Ni in a planetary mill for 30 h at 250 rev min⁻¹. As a second step, intermetallic SmCo₅ 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, Cu_90−xCo₁₀Ni_x–7.5% SmCo₅ 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 SmCo₅.

KEYWORDS:

• Cu–Co–Ni–SmCo₅ composite
• mechanical alloying
• structural and magnetic properties

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Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Marta Lopez is a professor at the Department of Materials Engineering, Faculty of Engineering, University of Concepción, Concepción, CHILE. Her primary research interests are focused in copper composite alloys reinforced with intermetallics and magnetic particles which covers the area of powder metallurgy. She has more than 25 years of experience in this field.

Mangalaraja Ramalinga Viswanathan is a professor at the Department of Materials Engineering, Faculty of Engineering, University of Concepción, Concepción, CHILE. He has broad interest and expertise in nanotechnology-driven energy and environment materials and micro-nano-structure–property relationship. He is the author or co-author of over 125 refereed journal publications. Currently, he is the president of Chilean Metallurgy and Materials Society.

José A. Jiménez is a research scientist of the Spanish National Research Council (CSIC) at the National Center for Metallurgical Investigations (CENIM). He is the author or co-author of over 150 refereed journal publications covering microstructural characterisation, thermomechanical processing and mechanical properties of steels, intermetallic alloys and composite materials, that has been cited more than 1500 times.

ORCID

R. V. Mangalaraja http://orcid.org/0000-0003-1016-9830

Additional information

Funding

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.