STRUCTURE OF SOME REFRACTORY TRANSITION METAL-METALLOID GLASSES

The radial distribution functions of four refractory alloys of composition (W0.5Ru0.5)0.8M0.2 where M = some metalloid from the group B, P, Al0.5B0.5, Si0.5B0.5 are presented along with densities, atomic volumes of metalloids and coordination numbers. The atomic distributions functions of these materials have been found to exhibit characteristics typical of many other amorphous metal-metalloid alloys. A comparison was made between the experimentally determined distribution functions for the WRu alloys and the Bernal Finney model calculations of dense random packings of hard spheres using the average WRu Gold-schmidt radii as the hard sphere radius. The agreement was found to be quite good in nearly all places, the most notable exception being in the vicinity of the second maxima, where the relative heights of the double peaks is found to be different from the DRPHS for the cases of M = B, P and B0.5Si0.5. In all cases for the WRu alloys the reduced radial distribution functions suggest a local short range order favoring common-base tetrahedra configurations as opposed to coplanar tetrahedra bases predominant in the DRPHS. © 1979.