A thermoelastic method for the measurement of thermal expansion coefficient of solids

Abstract

A measurement method for the thermal expansion coefficient of elastic solids has been developed. The method exploits the thermoelastic effect, the dual effect of thermal expansion: it is based on elastic compression of a small cylindrical specimen by a simple accessory for a conventional material testing machine whose applications are extended to the measurement of thermophysical properties. Compression induces a temperature variation proportional to the ratio of thermal expansion coefficient to specific heat; the expansion coefficient is then derived by an independent measurement of specific heat. Temperature can be measured in both quasiadiabatic and nonadiabatic conditions, and also allows in situ characterization of the temperature sensor promptness. Precision and accuracy of the measured ratio have been assessed by Certified Reference Materials: they are comparable to those of other methods.