Room temperature Young's modulus, shear modulus, and Poisson's ratio of Ce 0.9Fe 3.5Co 0.5Sb 12 and Co 0.95Pd 0.05Te 0.05Sb 3 skutterudite materials

Abstract

Room temperature Young's modulus, shear modulus and Poisson's ratio were measured by Resonant Ultrasound Spectroscopy (RUS) for a total of 29 skutterudite specimens cut from four hot pressed billets: (i) two p-type (Ce 0.9Fe 3.5Co 0.5Sb 12) billets, (ii) one n-type (Co 0.95Pd 0.05Te 0.05Sb 3) billet with 0.1 atomic% Ce addition and (iii) one n-type billet without Ce addition. Within a given hot pressed billet, the elastic moduli were very uniform from specimen to specimen. Also, Ce-doping of the n-type specimens did not result in a significant shift in the elastic modulus. For n-type specimens with 98% relative density, the mean Young's modulus, shear modulus and Poisson's ratio were 140.6 ± 0.2 GPa, 57.34 ± 0.05 and 0.226 ± 0.001 GPa, respectively. For the p-type specimens of similar relative density, the mean Young's and shear moduli were approximately 7% lower than the n-type, while there was no significant difference between the mean Poisson's ratio values of the n-type and p-type 98% dense specimens. The measured elastic moduli agreed relatively well with the literature values for other Sb-based skutterudite compositions. In addition, nanoindentation measurements on three mutually orthogonal specimen faces showed no appreciable anisotropy in Young's modulus.