Thermodynamic parameters of tungsten at low temperature: evaluation from ultrasonic velocity data

Ultrasonic investigation of tungsten metal at low temperatures has been done using data taken from literature. Various acoustical and thermoelastic parameters such as longitudinal and shear sound velocities, Young's modulus, shear modulus, bulk modulus, Poisson ratio, Debye temperature, and Grueneisen parameter have been studied for the metal in the temperature range 5K to 75K. A large number of acoustical parameters such as average sound velocity, adiabatic compressibility, molar sound velocity, molar adiabatic compressibility, acoustic impedance and isothermal compressibility have also been evaluated for the tungsten metal. Latent heat of melting, latent heat of vaporisation, thermal conductivity, diffusion constant, interatomic distance, space filling factor and geometrical volume are some of the thermodynamical parameters investigated for the system. Rao-Padmini formulation have been used to predict the strength of interaction among the constituents of the system. The results have been explained in terms of the interatomic interactions present in the system. The present study provides a qualitative as well as quantitative knowledge about the behaviour of tungsten metal in the low temperature range. (author). 20 refs., 4 tabs