PNNL

Abstract

With growing efforts of electrification, aluminum’s role as a light-weight conductor material has become increasingly prominent. There is a critical need to improve the electrical performance of aluminum at room temperature and high operating temperatures. In this study, the effect of graphene nanoparticles on the electrical performance of non-heat treatable alloy were explored. Graphene’s unusual structure and electronic properties can be used to improve AA3003’s properties. Here, the effects of graphene on the evolution of electrical properties and microstructural features have been explored on bulk scale hot extruded AA3003-graphene composites. Hot pressing schedules and extrusion temperatures were varied to investigate changes in intermetallic dispersion characteristics in the presence of dispersed graphene. We measured a maximum reduction of 10.3% in the temperature coefficient of resistance in the AA3003 sample 0.05 wt.% graphene extruded at 400 °C, along with a maximum increase of 1.1% in electrical conductivity at 20 °C. Increasing the hot-pressing times up to 8 hours was also found to consistently increase the electrical conductivity, due to increased precipitation of Al(Mn,Fe)Si intermetallic phases. Despite being a non-heat treatable alloy, it has been shown that AA3003 displays interesting precipitation dynamics and grain recrystallization trends that can be modulated with varying levels of heat treatment, graphene concentrations, and hot extrusion process parameters.