Estimating enthalpy and bulk modulus from thermal expansion data — a case study with α-Al2O3 and SiC

A simple thermodynamic framework has been formulated for calculating elastic properties from a knowledge of thermal expansivity and specific heat or vice versa. This approach rests on the validity of two plausible assumptions. In the first, by assuming the ratio (λ) of thermal expansivity (αV) to isobaric specific heat (CP) to be temperature independent, certain approximate expressions connecting rather explicitly the temperature dependence of volume and enthalpy with that of bulk modulus have been derived. In the second step, where this ratio happens to be mildly temperature dependent, a different functional relationship between thermal and elastic quantities has been established by invoking the temperature independence of Anderson-Gruneisen (δS) parameter. The application potential of these relations in estimating the thermophysical data for the missing quantities from known ones has been investigated against α-Al2O3 and SiC by estimating their bulk moduli from respective thermal expansion and enthalpy data.