  Chemical segregation and structural transitions at interfaces are important
nanoscale phenomena, making them natural targets for atomistic modeling, yet
interatomic potentials must be fit to secondary physical properties. To isolate
the important factors that interatomic potentials must capture in order to
accurately model such behavior, the performance of four interatomic potentials
was evaluated for the Cu-Zr system, with experimental observations used to
provide validation. While experimental results show strong Zr segregation to
grain boundary regions and the formation of nanoscale amorphous complexions at
high temperatures and/or dopant compositions, a variety of disparate behaviors
can be observed in hybrid Monte Carlo/molecular dynamics simulations of doping,
depending on the chosen potential. The potentials that are able to recreate the
correct behavior accurately reproduce the enthalpy of mixing as well as the
bond energies, providing a roadmap for the exploration of interfacial phenomena
with atomistic modeling. Finally, we use our observations to find a reliable
potential for the Ni-Zr system and show that this alloy should also be able to
sustain amorphous complexions.

Materials Science