Effect of CNT’s volume fraction on the mechanical properties of CNT reinforced Al/Cu alloy nanocomposite using molecular dynamics simulation

Abstract

Aluminum is one of most widely available elements on planet earth. After oxygen and silicon, aluminum is the third available element in the crust of the earth with a contribution of about 8%. It has a unique set of properties for which it has been used heavily in different aspects of life but yet its mechanical properties such as strength and hardness may be enhanced by the addition of other elements to form an alloy or a composite. Carbon nanotubes (CNTs) have attracted a great attention as reinforcements in metal matrix composites due to their extraordinary characteristics such as strength, stiffness, and low density. Aluminum/Copper (Al/Cu) alloy enhanced with CNTs of different volume fractions is the topic of this work which was not addressed previously in the literature. Embedded atom method (EAM) potential was used to model the interaction between aluminum and copper while the Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potential was used to model the CNT. The interactions between Al/Cu alloy and CNT was modeled using the pairwise Morse potential. Mechanical properties of Al/Cu alloy with alloying percentage of 10% reinforced with single walled carbon nanotube of different volume fractions are studied under tensile loading using molecular dynamics (MD) simulation. The open-source code LAMMPS is used to conduct the MD simulations. An armchair CNT with a chirality of (6,6) is considered for the study. The modulus of elasticity and the ultimate tensile strength of the Al/Cu-CNT nanocomposite are both observed to increase as the volume fraction of the CNT increases. The modulus of elasticity increased by almost 75% as the volume fraction of the CNT increased from 1% to 10%. The failure strains are almost the same in all cases. The results showed a maximum practical threshold of 10% CNT volume fraction to the Al/Cu alloy.