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.