Interdiffusion of Ni-Al multilayers: a continuum and molecular dynamics study

TL;DR

This study uses molecular dynamics and continuum modeling to analyze Ni-Al multilayer interdiffusion, revealing temperature-dependent reaction pathways, mechanisms, and activation energies.

Contribution

It provides a detailed comparison of interdiffusion mechanisms across temperature regimes using both molecular dynamics and continuum approaches.

Findings

Fickian diffusion dominates at high temperatures

Ni dissolution into Al liquid occurs at intermediate temperatures

B2 intermetallic forms early at low temperatures

Abstract

Molecular dynamics simulation of Al/Ni multilayered foils reveals a range of different reaction pathways depending on the temperature of the reaction. At the highest temperatures Fickian interdiffusion dominates the intermixing process. At intermediate temperatures Ni dissolution into the Al liquid becomes the dominant mechanism for intermixing prior to formation of the B2 intermetallic phase. At lower temperatures the B2 intermetallic forms early in the reaction process precluding both of these mechanisms. Interdiffusion and dissolution activation energies as well as diffusion prefactors are extracted from the simulations.