An MD-study on changing the elemental distribution and composition by alloying to control front propagation in Al-Ni multilayers

Abstract

To cover the wide range of applications of reactive multilayers, it is necessary to have the ability to vary and control their front propagation velocities as well as their maximum reaction temperatures. In this paper, Molecular Dynamics simulations are used to study the influence of Al alloying, Ni alloying, and Co alloying on Al-Ni multilayers. In the case of alloying with Al and Ni, the iso-stoichiometric case where both the Al and the Ni layers are alloyed is first studied. In the second step, the stoichiometry is varied by alloying only one of the two layers with the other element. This allows for achieving very small front propagation velocities. Furthermore, the Ni layer is alloyed with Co and the whole range from a binary Al-Ni to the binary Al-Co system is studied. The front propagation velocity does not change linearly with the alloying fraction and reaches a minimum where the Ni/Co alloy changes from a face centered cubic to a hexagonal close packed lattice.