Mössbauer effect study of fine atomic structure of Fe50Al40Ni10 powders

► Bhf decreases with increasing milling time due to the diffusion of Al and/or Ni into Fe grains. ► One Ni atom diffuses inside the first coordination sphere of Fe. ► Bhf values ranging from 30 to 33 T have to be partially attributed to Fe crystalline grains. ► Bhf values ranging from 15 to 30 T can be associated to the nanocrystalline Fe(Al, Ni) solid solution. ► Bhf values (<15 T) result from Fe atoms located in the disordered grain boundaries.