چكيده به لاتين
Having the high strength to weight aspect ratio, aluminum is the most common material using in metal matrix composites, comparing to other light metals. However, its low tensile strength limited its application. Hence investigation on graphene reinforced aluminum-based composites as a substitution material for qualify better mechanical strength become the interest of study nowadays. Because of discontinuity in nanoscale, continuum theories can't be used. Therefore the best alternative is the molecular dynamics method which is based on the classical mechanic that trustable softwares are developed for this purpose recently. In this study, molecular dynamic simulations are applied on aluminum graphene composite. Mechanical properties of aluminum, graphene and the aluminum-graphene nanocomposite are studied using uniaxial loads and two ends stretching. The interactions between the atoms of Al are modeled using Embedded Atom Method (EAM) potentials, whereas Adaptive Intermolecular Reactive Empirical Bond-Order (AIREBO) potential is used for the interactions among carbon atoms and these pair potentials are coupled with the Lennard-Jones (LJ) potential. The result shows that the incorporation of Gn into the Al matrix can increase the Young's modulus and the tensile strength of the nanocomposite substantially. Adding 0.78% wt graphene to aluminum, the Youngs module, and the tensile strength will increase to 13 Gpa and 2.3 Gpa respectively. Simulation data show that temperature, strain rate, and structural defects affect not only the mechanical properties of a single crystal of aluminum but also the mechanical properties of the nanocomposite. Also, results show that increasing in temperature and the void diameters and decreasing in strain rate results in lower mechanical properties such as Young module and tensile strength that are in good agreement with experimental values in macro scale. Results from the molecular dynamics simulations are also compared with analytical results obtained from semi-empirical Halpin-Tsai (H-T) model and the Rule of Mixtures (ROM).
Molecular Dynamic, Aluminum, Graphene, Nanocomposite, Mechanical properties
