Structure-Property Relationships in Nanocarbon-Al Composites Made by an Electrocharging Assisted Process

Carbon nanostructures are a growing area of research due to their excellent mechanical, electrical and thermal properties. Electrocharging assisted processing of a novel class of materials, termed “covetics,” presents a practical option for macroscale production of nanocarbon-metal composites. This process incorporates carbon on the order of a couple weight percent in metals where carbon solubility is in the low ppm range. Increased tensile strength and electrical conductivity have been measured in Al covetics; however, there is minimal understanding of the structure-process-property relationship and there is high variability in measured properties among trials. We have found that the activated carbon precursor is converted to sp² graphitic carbon with increased crystallite size. XRD and XPS show no measurable formation of carbide phases. The local electromechanical behavior measured by nanoindentation and AFM gives insight into a fundamental understanding of the improved properties in covetics, and is used to improve the fabrication process for maximal increase in electrical conductivity and tensile strength.