Enhanced Conductivity Aluminum Composites for Lightweight Transportation Applications

Wednesday, September 15, 2021: 4:20 PM
223 (America's Center)
Mr. Aditya K. Nittala , Pacific Northwest National Laboratory, Richland, WA
Mr. Lloyd Furuta , Ohio University, Athens, OH
Dr. Frank Kraft , Ohio University, Athens, OH
Dr. Alex Poznak , Hydro Innovation & Technology, Troy, OH
Mr. Kashi Subedi , Ohio University, Athens, OH
Dr. David Drabold , Ohio University, Athens, OH
Dr. Xiao Li , Pacific Northwest National Laboratory, Richland, WA
Dr. WoongJo Choi , Pacific Northwest National Laboratory, Richland, WA
Dr. Keerti Kappagantula , Pacific Northwest National Laboratory, Richland, WA
Aluminum has been at the forefront of the evolution of lightweight technologies for structural enhancements, to aid improvements in fuel efficiencies of mobile applications. The gradual adoption of automobiles with electric powertrains necessitates the very important need to improve electrical conductivities and power densities of metal substrates used. Compared to traditionally used copper, pure aluminum is only 61% as conductive, but is only 30% as dense. Thus, aluminum has a huge potential for playing a substantial role in the light weighting of automotive electric systems.

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.