The Influence of Chemical Short Range Order on Atomic Diffusion in Al-Ni Melts

TL;DR

This study combines neutron scattering and molecular dynamics simulations to explore how chemical short range order affects atomic diffusion in Al-Ni melts, revealing composition-dependent diffusion behavior linked to atomic packing.

Contribution

It provides new insights into the relationship between chemical short range order and atomic diffusion in Al-Ni melts using combined experimental and simulation approaches.

Findings

Diffusion coefficients vary non-linearly with composition.

CSRO changes correlate with atomic packing density.

Diffusion increases significantly on the Al-rich side.

Abstract

We use inelastic neutron scattering and molecular dynamics (MD) simulation to investigate the chemical short range order (CSRO), visible through prepeaks in the structure factors, and its relation to self diffusion in Al-Ni melts. As a function of composition at 1795K Ni self diffusion coefficients from experiment and simulation exhibit a non-linear dependence with a pronounced increase on the Al-rich side. This comes along with a change in CSRO with increasing Al content that is related to a more dense packing of the atoms in Ni-rich Al-Ni systems.