Microscopic and spectroscopic evaluation of SPS sintered aluminium-graphene (Al-Gr) nanocomposites
Vipin Jain, Anil Kumar, Ajay Dhar
Volume 2, Issue 3, Page 146-151, Year 2017 | DOI: 10.5185/amp.2017/303
Keywords: Graphene, nanocomposites, raman spectroscopy, SPS, electron microscopy.
Abstract: Graphene possesses excellent properties such as, high Young’s modulus (1 TPa), high fracture strength (~125 GPa) and extreme thermal conductivity (~5000 W/m/K), therefore, can serve as an ideal reinforcement material for the metal based High Tech structural nanocomposites. In the present work, a novel chemical synthesis method has been adopted for the in-situ synthesis of aluminium-graphene (Al-Gr) nanocomposite powders with varying compositions using graphene oxide (GO) as the precursor. The pure aluminium powder was initially cryomilled to refine the crystallite size. Subsequently, Al-reduced graphene (Al-Gr) nanocomposite powders were synthesized employing different volume proportions of GO (referred as 0.5, 2, 4, and 6 ml) dispersed in deionized water. The synthesized nanocomposite powders were ball milled followed by consolidation using spark plasma sintering under the optimized conditions. The nanocomposite powder as well as SPSed samples were characterized using X-ray diffraction (XRD), Raman Spectroscopy and electron microscopy. Scanning electron microscopy (SEM) studies of nanocomposite powders have depicted wrinkled structure typical of reduced graphene. Raman spectra have shown regular D, G, 2D and D+G bands and a modulated 2D peak having intensity significantly less than the G peak was observed for the nanocomposite powders confirming multilayered graphene is synthesized. The graphene wrinkles were determined in the size of 100 nm or more. Microhardness of SPS sintered nanocomposites is found progressively increased with the increasing content of reduced graphene with up to 58% improvement over pure Al was observed for the maximized GO content depicting potential for energy efficient high strength applications. The synthesized Al-graphene nanocomposites are novel in terms of an innovative, indigenously developed and scalable to bulk synthesis approach based on in-situ chemical synthesis route adopted. Copyright © 2017 VBRI Press.