Characterization of Aluminum Carbide in Aluminum-Graphene Nanocomposites

Characterization of Aluminum Carbide in

Aluminum-Graphene Nanocomposites

 

Aditya Nittala¹, Frank Kraft², Keerti Kappagantula^1,2

¹Nanomaterials and Energetic Systems Lab,

²Center for Advanced Materials Processing,

Department of Mechanical Engineering,

Russ College of Engineering and Technology,

Ohio University, Athens Ohio 45701

Abstract

Recently, there has been an increased interest in investigating the effects of reinforcing aluminum matrix with nanoscale carbon additives such as carbon nanotubes and graphene nano-films (GNF) to make metal nanocomposites with enhanced mechanical, thermal, and electrical properties. In general, CNTs and GNFs have shown an ability to influence the macro-scale properties of the substrates they have been introduced into as reinforcements. In particular, in graphene reinforced aluminum nanocomposites, ensuring optimal material contact at the interface between the aluminum matrix and the graphene reinforcement is paramount for ensuring desired mechanical, thermal, and electrical properties of the nanocomposite. A typical interfacial phenomenon observed in aluminum/graphene nanocomposites is the formation of aluminum carbide (Al₄C₃) owing to a chemical reaction between aluminum matrix and the carbon present in the graphene film. While small quantities of Al₄C₃ have shown an improvement in the mechanical properties of the constituent nanocomposite, it is undesirable as an insulator and decreases the electrical and thermal properties of the material system. Thus, controlling the amount of Al₄C₃ formed at aluminum-graphene interface can lead to the development of nanocomposites with precisely designed mechanical, electrical, and thermal properties for specific applications.

While there is variegated information present of aluminum carbide formation, there is no literature clearly delineating the mechanism and conditions for carbide formation in aluminum-graphene nanocomposites. The present research explores the quality, quantity and topography of aluminum carbide formed in aluminum/graphene nanocomposites. Aluminum/graphene nanocomposite samples are synthesized with varying graphene content by hot-extrusion method performed at a range of temperatures from 300°C to 600°C. Aluminum carbide is characterized using electron beam microscopy and spectroscopy methods. Aluminum carbide formation in the nanocomposite is described as a function of graphene and aluminum matrix interface, graphene film quality, and the rate of energy provided to the nanocomposites during their synthesis. Additionally, the effect of aluminum carbide content on the thermal, electrical, and mechanical properties of the nanocomposite is determined. The results from the study are used to determine thermodynamic conditions conducive for aluminum carbide formation such that its quantities can be predictively anticipated and controlled to make aluminum/graphene nanocomposites with prescribed mechanical, thermal, and electrical properties.