Structural stability and magnetic properties of metastable Fe-Cu alloys studied by ab initio calculations and molecular dynamics simulations

摘要

For the equilibrium immiscible Fe-Cu system, ab initio calculations using the projector augmented wave method identify the relatively stable structures of the metastable Fe_(25)Cu_(75) and Fe_(50)Cu_(50) alloys to be both of fcc and determine their corresponding lattice constants and cohesive energies. Some of the ab initio calculated properties are used in deriving an embedded-atom Fe-Cu potential. Based on the proven realistic potential, the structural stability of the Fe_xCu_(100-x) alloy is studied for the entire composition range of the system through molecular dynamics simulations. The simulations predict that a fcc structure is more stable than a bcc one when 0≤x≤60, while the bcc structure becomes energetically favored when 60