Correlation of temperature dependences of thermal expansion and heat capacity of refractory metal up to the melting point: Tungsten

In continuing the series of publications started by the article about molybdenum, a detailed study of the correlation between the volume thermal expansion coefficient, omicron(T), and the heat capacity, C(T), of another refractory metal, tungsten, is carried out. It is shown that a distinct correlation of omicron(C) takes place not only at low temperatures, where it is linear and is known as the Gruneisen law, but also within a much wider temperature region, up to the melting point of the metal. A significant deviation from the low-temperature behavior of the linear dependence of omicron(C) occurs when the heat capacity reaches its classical Dulong and Petit limit, 3R. The concept of the temperature dependence of the differential Gruneisen parameter, gamma' similar to (a,omicron/a,C) is introduced, and its evaluation is proposed