Enhanced tensile properties of aluminium matrix composites reinforced with graphene encapsulated SiC nanoparticles

• Published in: Composites. Part A, Applied science and manufacturing Vol. 68; pp. 155 - 163
• Main Authors: Fadavi Boostani, A., Tahamtan, S., Jiang, Z.Y., Wei, D., Yazdani, S., Azari Khosroshahi, R., Taherzadeh Mousavian, R., Xu, J., Zhang, X., Gong, D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2015
• Subjects: A. Graphene sheets; A. Metal-matrix composites (MMCs); Agglomeration; Aluminum base alloys; B. Mechanical properties; E. Casting; Encapsulating; Graphene; Metal matrix composites; Nanostructure; Particulate composites; Silicon carbide; B. Mechanical properties; E. Casting; A. Graphene sheets; A. Metal-matrix composites (MMCs)
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/j.compositesa.2014.10.010

Due to a high propensity of nano-particles to agglomerate, making aluminium matrix composites with a uniform dispersion of the nano-particles using liquid routes is an exceptionally difficult task. In this study, an innovative approach was utilised to prevent agglomeration of nano-particle by encapsulating SiC nano-particles using graphene sheets during ball milling. Subsequently, the milled mixture was incorporated into A356 molten alloy using non-contact ultrasonic vibration method. Two different shapes for graphene sheets were characterised using HRTEM, including onion-like shells encapsulating SiC particles and disk-shaped graphene nanosheets. This resulted in 45% and 84% improvement in yield strength and tensile ductility, respectively. The former was ascribed to the Orowan strengthening mechanism, while the latter is due primarily to the fiber pull-out mechanism, brought about by the alteration of the solidification mechanism from particle pushing to particle engulfment during solidification as a consequence of high thermal conductive graphene sheets encapsulating SiC particles.