A neutron diffraction study of the annealing behavior of Al-Fe alloys prepared by ball milling

We have obtained supersaturated bcc AI(Fe) nanocrystalline solid solutions after milling Al66Fe34 and Al75Fe25 powders for extended mechanical treatment. The evolution of structural and microstructural parameters during ball milling was followed by neutron diffraction experiments using a high-resolution powder diffraction instrument at the ISIS-pulsed neutron source (Chilton, UK). Quantitative evaluation of all patterns collected have been carried out with the Rietveld method, which enabled us to follow the early stages of intermixing by ball milling, as well as fragmentation and lattice damage induced by the extended mechanical treatment. Changes in the magnetic properties during the mechanical treatment were also followed by Mossbauer spectroscopy. Further annealing experiments were conducted in situ and showed that the metastable AI(Fe) solid solutions were subjected to a sudden phase transformation at moderately low temperature (approximate to 310 degreesC) with formation of Al5Fe2 intermetallic.