The adiabatic elastic constants of magnesium single crystals have been measured by an ultrasonic pulse technique. The values at 298°K are in good agreement with the recent values of Long and Smith. The values extrapolated to 0°K are $c_{11}=0.635\mathrm{}$, $c_{33}=0.664\mathrm{}$, $c_{44}=0.1842\mathrm{}$, $c_{12}=0.259\mathrm{}$, $c_{13}=0.217\mathrm{}$ in units of ${10}^{12}$ dynes/${\mathrm{cm}}^2$. A Debye characteristic temperature, $\theta$, of 388±3°K has been calculated at 0°K by averaging the inverse cube of the longitudinal and transverse elastic wave velocities over all directions of propagation. Atomic force constants for a central-force model with an electron gas term are also obtained.

• Received 1 May 1957

DOI:https://doi.org/10.1103/PhysRev.107.972