Copper-Coated Graphene Nanoplatelets-Reinforced Al–Si Alloy Matrix Composites Fabricated by Stir Casting Method

Abstract

In this study, Cu nanoparticles-coated graphene nanoplatelets (Cu-NPs@GNPs) were synthesized by a simple in situ method with the assistance of NaCl templates and used for reinforcing Al-10Si composites through stir casting process. The experimental results showed that the coating of Cu-NPs on the GNPs could compromise the density mismatch between GNPs and metal matrix and effectively hinder the float of GNPs during stirring. The reaction of Cu-NPs and Al matrix could protect the structural integrity of GNPs as well as improve the interfacial wettability between GNPs and the matrix, thus promoting the uniform dispersion of GNPs in the composites. As a result, the as-prepared 0.5 wt% Cu-NPs@GNPs/Al-10Si composite exhibited a tensile strength of 251 MPa (45% higher than the Al-10Si) with a total elongation of 15%. The strengthening effects were mainly attributed to the following three reasons: Firstly, the Cu-NPs coating improved the interfacial bonding between GNPs and Al matrix which promoted the load transfer from the matrix to the GNPs. Secondly, the nanoscale Al 2 Cu formed by the reaction of Cu-NPs and Al matrix played a role in precipitation strengthening. Thirdly, GNPs refined the silicon phases and improved the monolithic performances of the composites.

Effect of the Stirring Velocity and the SiO2 Precursor Particles Feeding Rate on the Microstructure of the Al2O3/SiO2/Al Composites Prepared via Stir Casting Process

“…To generate the reinforcements in the aluminum matrix, the in situ method requires the precursors bulk (usually fabricated by cold pressing the mixture of SiO 2 particles and the binder) should be prepared beforehand. [24,25] However, if the vol% of precursor particles in the bulk is relatively high or the diameter of the particles is small, the particles would tend to agglomerate in the melts. The ex situ technique, by incorporating the precursor particles into the stirring vortex of the melts, might be more effective to prevent the agglomeration of particles under the stir casting preparation.…”

“…In order to homogeneously mix the molten aluminum alloys and the light reinforcement precursors, the stir casting process should be carried out. Han et al [ 24 ] investigated the strengthening effect of copper‐coated graphene reinforcement on the Graphene/Al‐Si composites fabricated via the stir casting process. They found that the copper‐coated graphene/Al interface with a good bonding.…”

Microstructural and Mechanical Properties Characterization of Graphene Oxide-Reinforced Ti-Matrix Composites

“…Compared with the common materials, graphene has excellent mechanical properties, thermal and electrical conductivity [11][12][13][14]. As a reinforcing phase, graphene was widely used to improve the properties of metal-matrix composites [15][16][17][18][19]. Shin et al [20] reported that few-layer graphene-reinforced Al-matrix composites by powder metallurgic method.…”