ELASTIC-CONSTANTS OF FE(NI,CO)-B GLASSES

Densities and Poisson's ratios are reported for two series of metallic glasses, (FeCo)80B20 and (FeNi)80B 20. These results are combined with extensional acoustic-wave velocity measurements, previously reported, to provide a characterization of the elastic stiffnesses of these glasses. The Poisson's ratios for both series of alloys peak at intermediate compositions, reflecting essentially similar sharp peaks in the bulk stiffnesses. Shear stiffnesses are relatively insensitive to composition, especially for the Fe-Co-B alloys. The hardnesses of the alloys appear to vary in proportion to their shear stiffnesses.