Microstructure-Sensitive Calculations of Metal Nanocomposite Electrical Conductivity

Recent computational and experimental studies on copper/graphene composites indicate the potential for graphene additions to improve upon the conductive properties of polycrystalline copper. In order to ascertain the effect of these additions and disambiguate their contribution with respect to microstructure on their ultimate conductivity, we have developed a finite difference-based calculation of electrical conductivity as a function of microstructure. To this end, the effects of grain size, texture, dislocation density, and graphene content on the conductivity of the copper/graphene nanocomposites were evaluated. Additionally, a parameter study was performed to evaluate the effect of graphene on the copper grain boundaries on the associated change in grain boundary conductivity. For this study, a range of grain size, grain boundary coverage, and change in grain boundary properties were considered. Our calculations indicate that high grain boundary coverage with graphene at grain sizes smaller than 1 μm could result in appreciable increases in bulk electrical conductivity of the composite. As a point of comparison, inserted twin grain boundaries were found to slightly improve net electrical conductivity for an equivalent average grain diameter. The effect of intragranular graphene additions on the net electrical conductivity are also discussed.