Influence of chemical short-range order on atomic diffusion in Al-Ni melts

We use inelastic neutron scattering and molecular dynamics 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 1795 K, Ni self-diffusion coefficients from experiment and simulation exhibit a nonlinear 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. (C) 2005 American Institute of Physics.