ANOMALOUS ELASTIC PROPERTIES IN A C-15 LAVES-PHASE COMPOUND

Low-temperature (70-300 K) elastic constants of a C15 Laves-phase compound Hf25V60Nb15 have been studied using resonant ultrasound spectroscopy. The results show anomalous elastic properties in this intermetallic alloy. The shear modulus and Young's modulus increase with increasing temperature. The bulk modulus is virtually constant in the tested temperature region. The room-temperature shear elastic constants of the alloy are smaller than those of the constituent elements and the average values derived from the rule of mixtures. The room-temperature Poisson's ratio of the alloy is higher than those of the constituent elements. The elastic properties of the C15 compound can be qualitatively understood using the electronic structure obtained from ab-initio calculations.