Molecular Dynamics Studies in Nanojoining: Self-Propagating Reaction in Ni/Al Nanocomposites

Abstract

Reactive joining with Ni/Al nanocomposites is an innovative technology that provides an alternative to more common bonding techniques. This work focuses on a class of energetic material, produced by high energy ball milling and cold rolling. The initial microstructure is more complex than that of reactive multilayer nanofoils, produced by magnetron sputtering, in which the bilayer thickness is constant. Typical samples are composed of reactive nanocomposite particles that are numerically modelized by randomly distributed layered grains. The self-propagating reaction was studied by means of molecular dynamics simulations. We determined the front characteristics and investigated the elemental mechanics that trigger propagation. Both dissolution of Ni in amorphous Al and sustained crystallization of the B2 -NiAl intermetallic compound were found to contribute to the heat delivered during the process.

Molecular dynamics simulations of nanoscale solidification in the context of Ni additive manufacturing

“…The simulations were performed using the Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) software [30], and the Embedded Atom Method (EAM) potential, developed by Purja Pun and Mishin for Ni-Al systems [31]. This potential has been extensively used to study reactivity in Ni-Al nanofoils [32,33]. In addition, this potential is known to reproduce well the physical and thermodynamical properties of nickel [34] (See We considered a pseudo 2D system in a simulation box of 100 nm × 1.4 nm × 200 nm.…”

A Molecular Dynamics Study of Ag-Ni Nanometric Multilayers: Thermal Behavior and Stability

“…The self-propagating exothermic reaction in Al-Ni N2Ms was first investigated at the nanoscale using MD simulations in [ 13 ]. The propagation of the reaction front has also been studied in Al-Ni nano-laminated composites with a complex structure, as reported in [ 14 , 15 ]. Different microstructures, namely amorphous, single crystal, columnar grains, and randomly oriented grains of varying size, were considered to evaluate their influence on propagation characteristics [ 16 ].…”