(398bl) 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.