TITLE:
Development of Cu-Exfoliated Graphite Nanoplatelets (xGnP) Metal Matrix Composite by Powder Metallurgy Route
AUTHORS:
Syed Nasimul Alam, Lailesh Kumar, Nidhi Sharma
KEYWORDS:
Powder Metallurgy, Exfoliated Graphite Nanoplatelets (xGnP), Cu-Based Metal Matrix Composite, Sliding Wear
JOURNAL NAME:
Graphene,
Vol.4 No.4,
October
19,
2015
ABSTRACT: In the present investigation the possibility of using exfoliated graphite nanoplatelets (xGnP) as
reinforcement in order to enhance the mechanical properties of Cu-based metal matrix composites
is explored. Cu-based metal matrix composites reinforced with different amounts of xGnP
were fabricated by powder metallurgy route. The microstructure, sliding wear behaviour and
mechanical properties of the Cu-xGnP composites were investigated. xGnP has been synthesized
from the graphite intercalation compounds (GIC) through rapid evaporation of the intercalant at
an elevated temperature. The thermally exfoliated graphite was later sonicated for a period of 5 h
in acetone in order to achieve further exfoliation. The xGnP synthesized was characterized using
SEM, HRTEM, X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy.
The Cu and xGnP powder mixtures were consolidated under a load of 565 MPa followed by sintering
at 850°C for 2 h in inert atmosphere. Cu-1, 2, 3 and 5 wt% xGnP composites were developed.
Results of the wear test show that there is a significant improvement in the wear resistance of the
composites up to addition of 2 wt% of xGnP. Hardness, tensile strength and strain at failure of the
various Cu-xGnP composites also show improvement upto the addition of 2 wt% xGnP beyond
which there is a decrease in these properties. The density of the composites decreases with the
addition of higher wt% of xGnP although addition of higher wt% of xGnP leads to higher sinterability
and densification of the composites, resulting in higher relative density values. The nature of
fracture in the pure Cu as well as the various Cu-xGnP composites was found to be ductile. Nanoplatelets
of graphite were found firmly embedded in the Cu matrix in case of Cu-xGnP composites
containing low wt% of xGnP.