Monte Carlo Modeling of Interphase Boundaries in Cu-Ag and Cu-Ag-Au Alloys

Monte Carlo simulation, in conjunction with the embedded atom method, has been used to model the composition and structure of a semicoherent (001) interphase boundary separating coexisting Cu-rich and Ag-rich phases in a binary Cu-Ag alloy. The results are compared with earlier simulations of the same boundary in a Cu-Ag-Au alloy, in which Au was found to segregate to the interface, and the boundary was found to be unstable with respect to break-up into {111} facets. The boundary in the binary system is also unstable to faceting, but displays both {100} as well as {111} facets. It is concluded that Au segregation in the ternary alloy plays an important role in stabilizing the {111} facets. The interplay between the misfit dislocations present at the interface, and the compositional features of the boundary are also discussed.