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

A simple thermodynamic framework has been formulated for calculating elasti c properties from a knowledge of thermal expansivity and specific heat or v ice verse. This approach rests on the validity of two plausible assumptions . In the first, by assuming the ratio (lambda) of thermal expansivity (alph a (V)) to isobaric specific heat (C-P) to be temperature independent, certa in approximate expressions connecting rather explicitly the temperature dep endence of volume and enthalpy with that of bulk modulus have been derived. In the second step. where this ratio happens to be mildly temperature depe ndent, a different functional relationship between thermal and elastic quan tities has been established by invoking the temperature independence of And erson-Gruneisen (delta (S)) parameter. The application potential of these r elations in estimating the thermophysical data for the missing quantities F rom known ones has been investigated against alpha -Al2O3 and SiC by estima ting their bulk moduli from respective thermal expansion and enthalpy data. (C) 2001 Elsevier Science Ltd. All rights reserved.