Third-Order Elastic Constants of Zinc

The complete set of ten third-order elastic constants of zinc was determined from measurements of the hydrostatic and uniaxial stress dependence of ultrasonic velocity. The experiments were carried out using the two-specimen interferometric method on appropriately oriented single crystals of zinc. The magnitudes of $C_{222}$ and $C_{111}$ are largest, followed by $C_{333}$ which is less than one-third of $C_{222}$, whereas $C_{144}$ is the smallest of all. All the constants except $C_{155}$ are negative. The "macroscopic" values of the Grüneisen $\gamma$ for zinc are evaluated.