A Mössbauer Effect Study of the Icosahedrally Coordinated TiMnFeSi Phases

The Mössbauer spectra of the icosahedrally coordinated phases in the alloys Ti58Mn34.5Fe2.5Si5, Ti61Mn32Fe5Si2, Ti61Mn22Fe15Si2, and Ti63-yMn27Fe10Siy, where y = 2.5, 5.0, and 7.5, respectively, have been measured at 78 K. The resulting spectra are best fit with a distribution of quadrupole interactions which are linearly correlated with the isomer shift. The average quadrupole splitting, the shape, and the width of the distribution function indicate that the Mackay icosahedron is the principal building block in these materials