Dynamic response of aluminum-graphene layered nanocomposites under shock compression and release based on atomistic simulations

Abstract

To understand the role of aluminum-graphene (Al-Gr) interface, molecular dynamics simulations have been conducted to investigate the dynamic response of Al-Gr layered nanocomposites. The propagation law of shock waves is revealed and the dislocation nucleation at Al-Gr interface may dominate the plastic deformation mechanism at low impact velocities, which results in the propagation of stepped waveforms. In other words, Gr facilitates dislocation nucleation and its full development in each Al layer. At high impact velocities, Gr can hinder the forward propagation of BCC Al, although Gr can promote BCC nucleation. During shock release, Gr reduces the spall strength of the Al-Gr layered nanocomposites, and then the fracture is dominated by interface fracture, exhibiting single-layer or multi-layer delamination. Gr is found to undergo bending and folding, but Gr remains intact owing to its exceptionally high tensile strength and resistance to high temperatures. With the development of voids and cracks near the Al-Gr interface, the Al layer undergoes significant geometric deformation without internal fragmentation..