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Production and characterisation of graphene oxide reinforced aluminium matrix composites

Dasari, BhagyaLakshmi (2019). Production and characterisation of graphene oxide reinforced aluminium matrix composites. (Unpublished Doctoral thesis, City, University of London)

Abstract

The present work deals with the production of graphene oxide (GO) reinforced aluminium (Al) matrix composites via liquid infiltration and powder metallurgical routes. The experiments were carried out on the optimisation of the process parameters of the composites and these outcomes were considered as input parameters for the prediction of properties using finite element (FE) modelling. The experimental design includes three wt% of GO reinforcement, three compaction pressures and two sintering temperatures. The other parameters investigated were selection of solvent and stirring time. The solvent and stirring time were selected based on visual inspections. Liquid infiltrated composite powders were vaccum filtered, dried and then cold compacted at 500MPa, 540MPa and 580MPa of compaction pressures. The GO/Al samples were sintered in horizontal tube furnace assisted by Ar gas atmosphere. The metallographic study and chemical analysis were performed using a scanning electron microscopy (SEM) integrated with energy dispersive X-ray spectroscopy (EDXS) revealing the existence of GO particles/sheets on Al particles. The percentage of elements at various regions of the GO/Al composites both at powder level and after sintering were investigated. The crystallinity and phase detection of the GO/Al samples were conducted using X-ray diffraction (XRD) system with Cu-Kα radiation and 1.54Å wavelength. The presence of GO and number of layers of GO residing on the Al particles were analysed using micro Raman spectroscopy, this also revealed that there was no existence of aluminium carbide (Al4C3) phase as the carbide formation will deteriorate the properties of the end composites. The hardness properties of the as received Al and produced GO/Al composites were measured by micro Vickers diamond indentation. The hardness of the GO/Al composite increases by 36% compared to pristine Al when reinforced with 0.2wt% of GO which is better than the hardness of rGO/Al composites reported in literature. Indentation test was used to investigate the effect of addition of GO to the Al on strength, in which it was noted that the addition of GO led to the brittleness in GO/Al composites. The effect of existence of GO on Al particles, variation in volume fraction of GO and existence of GO layers on Al particles on mechanical properties of GO/Al composites were predicted using FE modelling. The findings from the simulation were compared with analytical modelling and experimental results obtained from the current research work. A good agreement between results of FE model, analytical model and experimental investigations were noted.

Publication Type: Thesis (Doctoral)
Subjects: T Technology > TJ Mechanical engineering and machinery
Departments: Doctoral Theses
Doctoral Theses > School of Mathematics, Computer Science and Engineering Doctoral Theses
School of Mathematics, Computer Science & Engineering > Engineering > Mechanical Engineering & Aeronautics
URI: http://openaccess.city.ac.uk/id/eprint/22005
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