Elastic constants of α’-phasePdHxover the temperature range 4–300 K

The elastic constants of α’-phase ${\mathrm{PdH}}_{\mathrm{x}}$ have been determined from ultrasonic velocity measurements for x up to 0.76 over the temperature range 4–300 K. For pure Pd and ${\mathrm{PdH}}_{0.67}$ the results are in good agreement with earlier measurements. The ${\mathrm{PdH}}_{0.76}$ data are for a higher hydrogen concentration than has previously been reported. The low-temperature concentration dependences of the Debye temperature and bulk modulus are given.