Characterization of mechanical properties of copper covetic wires
Copper and copper alloys are commonly used in various applications because of their ability to be formed and their excellent thermal and electrical properties. A new copper carbon alloy, called copper covetic, is showing promising properties. Copper covetic materials were prepared Third Millennium Metals, Inc., by adding carbon to molten copper 10200 while a DC current was applied. The samples had 3, 5, and 9 weight percent of carbon, as reported by manufacturers. We refer to them as CuC3, CuC5, and CuC9, respectively. Copper 10200 wire with no added carbon created using normal wire making processes was used as comparison and is referred to as CuC0. The samples were tested using a nanoindenter at a 10,000uN and 5,000uN maximum load. The nanoindentation test showed a decrease of elastic modulus as the maximum applied load increased. The highest value of elastic modulus for both loads was for the CuC5 sample, and the lowest value was for the CuC9 sample. The microindentation test performed at a 500 Pond load resulted in the CuC3 sample having the highest hardness and the CuC0 and CuC5 samples having the lowest hardness. The tensile test results showed an increase yield stress and ultimate tensile strength for the CuC3, CuC5, and CuC9 samples. The CuC3 and CuC9 samples had higher yield stress and ultimate tensile strength than the CuC5 and CuC0 sample. The elastic modulus values of all samples were low in comparison to other copper alloys. The fracture strain for the CuC5, CuC3, and CuC9 samples were lower than the CuC0 sample. A CuC9 thin sample was prepared in a Dual-Beam Focus Ion Beam for analysis in a Transmission Electron Microscope (TEM). The diffraction and images generated by the TEM show the possibility of carbon being incorporated into the copper sample. The results show promise for covetics for various industrial applications.
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