Third-Order Elastic Constants of Magnesium. I. Experimental

Abstract

The complete set of ten third-order elastic constants of magnesium has been determined from measurements of the hydrostatic-pressure and uniaxial-compression derivatives of natural sound velocities using an ultrasonic pulse-superposition technique. The specimen was neutron irradiated with an integrated exposure of 2 \ifmmode\times\else\texttimes\fi{} ${10}^{18}$ (fast) neutrons per ${\mathrm{cm}}^{2}$ to suppress dislocation effects. The results are ${c}_{111}=\ensuremath{-}6.63$, ${c}_{112}=\ensuremath{-}1.78$, ${c}_{113}=+0.30$, ${c}_{222}=\ensuremath{-}8.64$, ${c}_{123}=\ensuremath{-}0.76$, ${c}_{133}=\ensuremath{-}0.86$, ${c}_{333}=\ensuremath{-}7.26$, ${c}_{144}=\ensuremath{-}0.30$, ${c}_{155}=\ensuremath{-}0.58$, and ${c}_{344}=\ensuremath{-}1.93$ in units of ${10}^{12}$ dyn ${\mathrm{cm}}^{\ensuremath{-}2}$.