A model for evaluating and predicting high-temperature thermal expansion

In this paper, a new set of experimental data, α_VK_TV, representing the partial temperature derivative of the work done by the thermal pressure of the solid, is fitted by n terms of a modified Einstein model. Experimental data show that α_VK_TV, not α_VK_T, approaches a constant value at high temperature. Based on the observed linear relationship of isothermal bulk modulus with temperature at high temperature, thermal expansion can be evaluated by fitting α_VK_TV data. Our previous results have shown that at low temperature or for materials with less variable bulk modulus and expansivity, thermal expansion data can be simply approximated by an n term Einstein model. More generally and for many materials, α_VK_TV data resemble an isochoric specific heat curve. With this method, thermal expansion can be predicted at high temperatures from low and intermediate temperature range data. With accurate thermal expansion data, high temperature bulk moduli can also be predicted.