Authors: D.R. Forrest, I. Jasiuk, L. Brown, P. Joyce, L. Salamanca-Riba
Affilation: Naval Surface Warfare Center, United States
Pages: 560 - 563
Keywords: covetic, nanocarbon, composite, metal-matrix
Recent advances in nanomanufacturing have made it possible for large amounts (up to 6 wt.%) of nanoscale carbon to be retained as an integral second phase in metals such as aluminum and copper. The carbon is highly stable despite its presence not being predicted in phase diagrams, and it remains dispersed after remelting and resolidification. Here we present new results, revealing some unexpected properties: -The nanocarbon is detectable by EDS and XPS but not by analytic methods such as LECO and GDMS. -Nanocarbon raises the melting point and surface tension. -Nanocarbon warm-worked and cold-worked strengths are higher than the base metal. -The nanocarbon microstructure is more resistant to softening and grain growth at elevated temperatures. -Nanocarbon enhances thermal conductivity in the extrusion direction, and reduced in the transverse orientation. -Electrical conductivity is increased in aluminum, and maintained in copper. -The composites have higher density than would be predicted from the rule of mixtures.