Abstract
Icosahedral Al-Mn and Al-(MnFeCr) alloys were studied by neutron diffraction with scattering vectors up to 16 Å-1. The three partial pair distribution functions (PPDF) were obtained and the actual isomorphous substitution of the σ-FeCr mixture for Mn was confirmed. The PPDF for Mn-Mn indicates the existence of a manganese subnetwork rather similar to that found in the α(AlMnSi) crystalline phase. In particular the shortest Mn-Mn distances were found at 4.47 and 4.97 A