Time evolution of the structural short-range order during the mechanical milling of Fe–Co–Cu nanocrystalline alloys

The local order around Fe, Co, and Cu atoms was investigated by extended x-ray absorption fine structure spectroscopy in Fe–Co–Cu nanocrystalline alloys prepared by mechanical alloying. In order to study the time evolution of the alloying process, Fe₃₀Co₂₀Cu₅₀ samples were studied after several processing times. The analysis of the data shows that, in a first step, a binary Co–Cu alloy is formed, but iron remains separate in the form of nanocrystals with a high defect concentration. Afterwards, in a second step, the final ternary Fe–Co–Cu alloy with the face-centered-cubic structure is obtained.