Simulation calculations of surface segregation for Au–Cu alloys using an analytic embedded atom model

Abstract

AbstractThe key problem for applying the Monte Carlo (MC) method to segregation lies in the selection of an appropriate energy model for the simulations. Zhang et al. proposed a modified analytic embedded atomic method (MAEAM), which has been applied to a variety of fundamental problems in metals and alloys. We used this MAEAM and MC method for the simulations of segregation of AuCu and Au3Cu alloys. For the (100) surface, the calculations show that Au is enriched in the 1st layer (70 at% for AuCu, 99 at% for Au3Cu), while Cu is enriched in the 2nd layer (50–62 at% for AuCu, 35–48 at% for Au3Cu). The composition profiles are generally oscillating. For the (111) surface, we also found Au to be enriched in the 1st layer. However, Cu is not enriched in the 2nd layer, it reaches the bulk composition from 2nd to 4th layer. Au increases from 92 to 97 at% and 99 to 100 at% for Au3Cu(111) and (100), respectively, when the temperature varies from 1000 to 200 K, which is basically in agreement with the measurements for Au3Cu(100) by Taglauer et al. However, the Au concentration does not change for the AuCu alloy in the same temperature range. We also calculate the segregation energy, the simulation results agree qualitatively with the experimental data available. Our results demonstrate that the MAEAM model provides an effective means for simulating the segregation of alloys. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)