On the Effect of Slight Impurities on the Elastic Constants, Particularly the Compressibility of Zinc

The conclusion of Hanson that the elastic constants and particularly the compressibility of different grades of pure zinc differing only slightly in purity may differ by relatively large amounts is subjected to direct experimental test by compressibility measurements on the same grades of zinc as used by Hanson. Measurements on virgin material show no measurable difference. Apparent differences, both in compressibility and in the other elastic constants, are probably to be explained by small internal strains. Improved values are found for the compressibility of zinc as follows: $\{{90}^{\circ } \mathrm{orientation}, \frac{-\Delta l}{l_0},=1.57\mathrm{}\times {10}^{-7\mathrm{}}p-0.75\mathrm{}\times {10}^{-12\mathrm{}}{p}^2,\}\{0^{\circ } \mathrm{orientation}, \frac{-\Delta l}{l_0},=13.50\mathrm{}\times {10}^{-7\mathrm{}}p-7.68\mathrm{}\times {10}^{-12\mathrm{}}{p}^2,\}\{\mathrm{Volume}\mathrm{compression}, \frac{-\Delta V}{V_0},=16.64\mathrm{}\times {10}^{-7\mathrm{}}p-9.62\mathrm{}\times {10}^{-12\mathrm{}}{p}^2,\}$ at 30°C, $p$ in kg/${\mathrm{cm}}^2$.