Temperature dependence of the elastic constants of thoria specimens of varying porosity

Abstract

The temperature dependence of Young's and the shear modulus of 18 thoria specimens of porosities ranging from 3.7 to 39.4 percent have been measured by the dynamic resonance method. The temperature range of the measurements was from 25 to 1,300°C. The moduli decreased with increasing temperature in general accordance with the pattern observed for other polycrystalline materials. The relative decrease in modulus with temperature for all the materials was essentially independent of porosity up to about 800°C. Above this temperature the relative decrease in modulus for the high porosity specimens tended to be more rapid than for the low porosity specimens. Also, Poisson's ratio for any particular specimen remained constant over the entire temperature range of measurement.