Specific Heats of Zirconium Alloys at Low Temperatures

Abstract

The specific heats of dilute alloys of silver, cadmium, indium, tin, and antimony in hexagonal zirconium were measured from 1.2 to 4.5 deg K. For each alloy the specific heat obeyed the relation c = gamma T + BETA T/sup 3/ within the experimental error. All of these solutes increased gamma linearly with concentration and d gamma /dx was linearly related to the chemical valence of the solute. The increase in gamma in the tinzirconium alloys showed that all electrons outside closed shells cannot be treated as equivalent in the rigid band model of alloying. All of these solutes increased the density af states of zirconium, providing evidence for a zone overlap in the zirconium d band and for a small number of electrons in a new band. All of the solutes increased the lattice specific heat and the Debye temperature was a linear function of solute concentration for each of these alloy systems. The function d theta /dx was not simply related to the solute valence but showed a close correlation with the magnitude of the rate of change of the distance between atoms at 000 and 1/3, 2/ 3, and 1/2 of the hexagonal cell. Additions of tinmore » to zirconium did not change the average interaction potential of the BCS theory appreciably. (auth)« less