Enhanced Electrical and Thermal Conductivity of Wires Drawn from Cast Cu/Nanophase Composites

Multi walled carbon nanotubes MWNTs will be coated to enable wetting by molten OFHC copper. Coated MWNTs will be made into a preform and pressure infiltration cast with molten Cu to form a Cu/MWNT master composite. Master composites will be added to molten Cu and shear dispersed/diluted to form a melt that can subsequently be rheocast into Cu/MWNT ingots. The ingots will then be conventionally processed into wire for cable for shipboard electrical systems. The electrical conductivity of Cu wire can be increased by a factor of two to six depending upon the alignment of MWNTs, the proportion of MWNTs that have electronic (armchair) structure and the volume fraction of MWNTs incorporated into the wire. Electrical and thermal conductivity, OM/SEM/TEM microstructure will be characterized and mechanical properties will be measured on shear dispersed/diluted composites in Phase I. Phase II will be focused on integrating the shear dilution process with a rheocasting processes that can later be converted into a continuous casting process and for producing prototype lots of material. Phase II will also focus on identifying cost effective high performance MWNT sources.