VOLUME DEPENDENCE OF ELASTIC-MODULI AND THE BORN-DURAND MELTING HYPOTHESIS

The elastic moduli of nine metals, argon, krypton, xenon, silver bromide and benzene are examined as functions of isobaric dilatation from absolute zero to the melting point and in the melt. The isothermal bulk modulus, and in many cases the two shear moduli, each have a Gruneisen-type dependence on crystal volume. In all except the inert gases the isothermal bulk modulus is continuous with respect to volume through the melting expansion and in every case one of the shear moduli falls continuously to a value sufficiently close to zero at the volume of the melt at the freezing point, that fluidity results by thermal activation. The Born-Durand elastic-instability melting hypothesis is therefore essentially correct except that the shear modulus vanishes in the melt at the melting point rather than in the solid. © 1979 Taylor & Francis Group, LLC.