New fcc Phase Formed in Immiscible Fe-Cu System by Solid State Diffusion

Fe₇₅Cu₂₅ nano-multilayers were prepared by alternative deposition of pure Fe and Cu metals and then annealed in situ in transmission electron microscopy to investigate the structural phase transformation. A new phase was formed in the Fe-Cu multilayers by interdiffusion at 820°C for about I0min and was identified to be of fcc structure with a lattice parameter of 0.854±0.005nm.