Model of Heat Capacity in Volume Dimension

Abstract

Heat capacity is an important and fundamental thermodynamic parameter in materials. The temperature-dependent heat capacity (HC) was studied extensively. Here, the universal correlation between the experimental heat capacity C p and the coefficient of thermal expansion β in reference solids at high temperatures: C p = C o + Eβ (C 0 and E: constants) and the volume-dependent heat capacity C TE in the temperature range from several Kelvins to melting temperatures is quantitatively determined: C TE = Eβ, and a new phenomenological model of the experimental heat capacity below the melting temperature in the volume dimension is established:Previous harmonic and anharmonic HC models explain the HC at low temperatures and high temperatures, respectively. The new model successfully explains the HC at the whole temperature range below the melting temperature and quantitatively determines the change behavior of the temperature and volume in solids after absorbing the heat.

Scaling Behavior between Heat Capacity and Thermal Expansion in Solids

“…Our previous study shows a new heat capacity model by the correlation between the experimental heat capacity 𝐶 p and coefficient of thermal expansion (𝛽) in Al 2 O 3 and Cu. [16] In this work, we quantitatively analyze the experimental HC 𝐶 p and the coefficient of volumetric thermal expansion (𝛽) in a series of reference solid materials with the melting temperature 𝑇 m from 3695 K to 84 K, and find that there is a critical HC 𝐶 p0 for each of the reference solids: the experimental 𝐶 p is linearly dependent on the CTE 𝛽, below or above the critical value, respectively. The linear behavior is different from the quasi-parabolic result by Eqs.…”