Surface composition of dilute copper-gold alloys

Abstract

Monte Carlo simulations in conjunction with the embedded atom method have been used to assess the composition of the (100) surface of dilute copper-gold alloys. These simulations have been performed for alloys having bulk gold atom fractions ranging from 0.03 to 0.11, and for temperatures from 400 to 1000 K. The results of the simulations have been found to be consistent in form with an analytical expression based on a nearest-neighbor bond formalism, which takes into account possible order-disorder transitions at the (100) surface. Comparison of these modeling approaches with recent measurements of the surface composition of a polycrystalline Cu 0.93Au 0.07 alloy, indicates that experimental surface composition averaged over many surface orientations does not coincide with modeling results for the (100) surface. However, the modeling approach is validated by showing that its predictions are in good agreement with measurements of surface composition performed on the (100) surface of Cu 3Au.