Enhanced Conductivity Aluminum Composites for Lightweight Transportation Applications
In this presentation, we discuss strategies to enhance aluminum electrical properties, namely conductivity, temperature coefficient of resistance and current density, with no loss to other performance metrics such as mechanical strength and corrosion resistance using different solid phase processing technologies such as hot-extrusion and friction extrusion. As a nanocarbon allotrope, graphene demonstrates higher electron mobility and tensile strength compared to metals due to its 2-dimensional sp2 hybridized carbon atom array structure. This makes it a very attractive nanocomposite additive; there has been significant research being carried out in the past 15 years on the synthesis and applications of graphene in metallic nanocomposite structures. To enhance electrical conductivity at operating temperatures, various aluminum alloys were composited with graphite nanoparticle precursors. We performed process and composition optimization to identify composites with 2 – 5% higher electrical conductivity and 10% reduction in temperature coefficient of resistance. Microstructural analysis showed fully consolidated composites with homogeneously distributed graphene-like additives. We attributed the enhanced electrical performance to exfoliation of graphite nanoparticles into highly conductive graphene-like structures, along with strong interfacial interaction and minimal carbide formation.
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