Abstract
Effective models of the mechanical behavior of thermoelectric materials under device conditions require knowledge of the temperature-dependent elastic properties.Between room temperature and 600 K, Resonant Ultrasound Spectroscopy (RUS) measurements of the Young’s and shear moduli of three skutterudite thermoelectric materials, n-type Co0.95Pd0.05Te0.05Sb3(both with and without 0.1 atomic % cerium dopant) and p-type Ce0.9Fe3.5Co0.5Sb12, decreased linearly with temperature at a rate between -0.011 GPa/K and -0.013 GPa/K. In contrast the Poisson’s ratio was approximately 0.22 for the three materials and was relatively insensitive to temperature.For temperatures > 600 K, the elastic moduli decreased more rapidly and resonance peaks broadened indicating the onset of viscoelastic behavior.The viscoelastic relaxation of the moduli was least for Ce-doped n-type material, for which grain boundary precipitates may inhibit grain boundary sliding which in turn has important implications concerning creep resistance. In addition, powder processing of the n- and p-type materials should be done cautiously since submicron-sized powders of both the n- and p-type powders were pyrophoric
