Fabrication of bulk aluminum-graphene nanocomposite through friction stir alloying

Abstract

Friction stir alloying is primarily employed for the fabrication of surface composite to improve surface properties like hardness, wear resistance, and corrosion resistance without significantly affecting the bulk properties of the alloy. The present study demonstrates the novel method for the fabrication of bulk aluminum-graphene nanoplatelets composite by using friction stir alloying. Here, the novelty is shown through the method of graphene nanoplatelets incorporation in the stir zone. For this purpose, a channel is fabricated on the cross-sectional surface of the aluminum plate and filled with graphene nanoplatelets. It is then covered by the cross-sectional surface of another aluminum plate of same dimensions and friction stir alloying is carried out. Reference material (RM) is also fabricated at the same parameters without any graphene nanoplatelet reinforcements for the performance evaluation of the nanocomposite. The microhardness of the fabricated composite increased by ∼57% as compared to the reference material. However, the tensile strength of the fabricated Al-graphene nanoplatelet composites decreased marginally as compared to reference material. The strengthening of the composite is explained systematically by various mechanisms. The results of microhardness and tensile test were corroborated with various characterization methods such as optical micrographs, scanning electron microscopy, atomic force microscope, and X-ray diffraction.

Different reinforcement strategies of hybrid surface composite AA6061/(B4C+MoS2) produced by friction stir processing

“…In a different approach, in AA1050 matrix groove filled by secondary phase reinforcements SiC and Al 2 O 3 , covered by an aluminum plate rather than capping pass [25]. The grooves can be made on the cross-sectional surface of the plate, packed with secondary phase, compacted manually, and then the plates are clamped facing secondary phase-filled surfaces each other followed by friction stir processing [26]. Compared to a single macro groove, the multiple micro groove strategy achieved better secondary phase distribution with resultant properties [27].…”

The development of ultra-high aluminium graphene metal matrix composites (MMC) and improved the thermo-mechanical properties

“…Graphene may also be used to fill empty spaces. Therefore, a greater amount of graphene in the aluminium matrix results in a lower microhardness [1,15,16]. The fact that graphene can fix broken grain edges [1] implies it may be able to stop grains from developing altogether.…”

Effects of disc milling and indirect extrusion processing on mechanical properties of aluminum-graphene-composites with commercial GNPs

“…The D-band relates to the magnitude of defects or disorder in the crystal structure of graphene [9]. The 2D-band is related to number of graphene layers in the GNPs [10]. The defect density of GNPs can be predicted with the intensity ratios of D-band and G-band (ID/IG) and the number of graphene layers in the GNPs with the ratio of 2D-band to G-band (I2D/IG) [11].…”