Mechanical Properties of Electroformed Copper

1 Mechanical Properties of Electroformed Copper K.M.Y. P’ng and A.J. Bushby Centre for Materials Research, Queen Mary, University of London, London, E1 4NS Report on work conducted under DSTL contract N o RD 033-2389 1 Introduction Copper (Cu) is used extensively as electrical wiring due to its excellent electrical conductivity, in plumbing due to its malleability and as heat sinks due to its good thermal conductivity. However, the strength of pure copper is considered too low to be used in load bearing applications therefore its uses are limited. Recently, Morganic Metal Ltd has developed nanocrystalline copper manufactured by an electroforming process that has shown signs of being much stronger than normal bulk copper. The work aims to improve the current understanding of the structure and mechanical properties of the metal. At this initial development stage, characterisation of the material is the central issue. With soft metals such as Cu and nickel, the metallurgy – namely the grain size and chemistry maybe questioned. Therefore, these properties must be characterised with the appropriate experimental methods before the mechanical properties can be determined. This report describes the chemical, metallurgical and mechanical characterisation of this electroformed copper. Chemical characterisation was carried out using energy dispersive X-ray spectroscopy (EDS) as well as X-ray diffraction (XRD). Metallurgical characterisation was carried out using mainly transmission electron microscopy and scanning electron microscopy. Mechanical tensile testing of these samples was carried out using the British Standard for tensile testing of metals 1 . Elastic properties were determined by a variety of methods (Impact Resonance and Surface Acoustic Wave at NPL 2 , and nanoindentation at QMUL 3 ). Thermal tolerance was investigated by heat treating samples and determining tensile mechanical properties.

Mechanical Properties of Electroformed Copper

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