Experimental Overview of Complex Intermetallic Structures

A complete investigation of the Fourier space of complex intermetallic Mg39Al61 is reported. X-ray patterns reveal the reciprocal space of the whole system consisting in selective reflections and coherent diffuse scattering. Their temperature dependence are studied. Selective reflections are interpreted as incommensurately modulated states and a structural analysis of the coherent diffuse scattering is presented. The same type of coherent diffuse scattering curve was also observed in several quasicrystalline alloys. In all the studied cases, the disorder is interpreted by the presence of icosahedral arrangements that are reminiscent of Frank units in supercooled alloys.