The difficulty of isolating grain boundary components in the Mössbauer spectra of ball-milled materials: iron and silver–iron alloys

Although 57Fe Mössbauer spectroscopy is well known to be a particularly suitable method for the characterization of nanostructured solids, attempts to isolate spectral features that can be associated with grain boundaries encounter unexpected difficulties in the case of ball-milled or mechanically alloyed metallic materials. In this paper, the examples of ball-milled α-Fe and Ag(Fe) alloys prepared by mechanical alloying are discussed in order to show what kinds of structural information can still be extracted from the hyperfine parameters, in spite of the presence of large concentrations of lattice defects and long-range magnetic interactions.