Multiscale modeling of the shock-induced chemical reaction in Al/Ni composites

A multiscale modeling method was proposed to describe the shock-induced chemical reaction (SICR) in Al/Ni composites, especially with large particle sizes of hundreds of micrometers. A one-dimension reaction diffusion model was established firstly based on the Fick’s second law, by which the reaction and mass diffusion process between single Al and Ni particle were calculated. Two critical parameters in the reaction–diffusion model were determined. Furthermore, mesoscale simulation on SICR of Al/Ni composites was proposed. A subroutine to describe the SICR process was created based on Mie–Grüneisen equation of state and the reaction–diffusion model. The evolution of molar concentration for each constituent was used to analyze the initiation and develop of the reaction–diffusion process at microscale and mesoscale, from which the reaction efficiency was finally derived at macroscale. The calculated results showed that the reaction–diffusion process was significantly influenced by loading conditions, including particle velocities and loading periods. The intensification of loading conditions accelerated the consumption of reactants and the generation of reaction products. The reaction efficiency was a time-dependent parameter, which continued growing even when the shock wave had propagated through the materials. A reasonable agreement between the experimental and calculated results based on the multiscale model was achieved. Moreover, the temperature, the shock pressure, as well as the shock velocity, were found increased by the SICR behavior.