Shock Consolidation of Ni/Al Nanoparticles: A Molecular Dynamics Simulation

Shock-induced consolidations of Ni/Al nanoparticles, including the consolidation behavior, exothermic reaction, intermetallic compound formation, and spallation, were systematically investigated through molecular dynamics simulation. The simulation indicates that shock consolidation of Ni/Al particles consists of two steps. Firstly, after the spread of shock wave, the cavity is densely filled by the flow deformation of the Al particles. Then, the Ni and Al particles are tightly joined together at the atomic scale by the produced high pressure and temperature. The exothermic reaction in the compressed particles is because the Ni atoms diffuse into the Al phase. Depending on whether melting takes place or not, shock consolidation can be divided into solid-state consolidation and liquid-state consolidation. In the solid-state consolidation, Ni/Al composite can be acquired with a little exothermic reaction. However, in the liquid-state consolidation, much more heat is released and intermetallic phase is formed. The spallation in the compressed particles is mainly because of the generated high-strength tensile wave but can be avoided by reducing the initial density of the Ni/Al particles or the particle velocity.