Atomistic Modeling of Metastable Phase Selection of a Highly Immiscible Ag-W System

Ab initio calculation is performed for predicting the cohesive energies and lattice constants of some possible metastable compounds in the Ag-W system with the largest positive formation enthalpy among the binary transition metal alloys. The calculated results together with the experimental data are then used in deriving an n-body Ag-W potential under the framework of the embedded atom method. Based on the proven realistic Ag-W potential, molecular dynamics simulations are performed to reveal the metastable phase selection over the entire composition of the system and the results predict that the metastable Agioo-_xW_x alloy in an fcc structure is more stable than in the bcc structure when 0 < x < 57, whereas the bcc structure becomes energetically favored when 57 < x < 100. Interestingly, the prediction is in good agreement with the experimental results.