Internal Friction of Lead. I

Abstract

Internal friction of single crystal of lead (99.99% pure) was measured with longitudinal vibration in kilocycle range using the composite piezoelectric quartz oscillator. The dependences of the internal friction on the strain amplitude (0.5-12×10 ^-6 ), on the frequency (64, 192 kc/sec) of vibration, and on temperature (140–340°K) were mainly studied. The internal friction is of the order of 10 ^-3 at low temperatures, and increases slightly as the temperature is raised, and increases also with increasing strain amplitude. Near the room temperature, the value of the internal friction rises steeply. A peculiar temperature (about 300°K) has been found above which the internal friction decreases with increasing amplitude. The amplitude-dependent internal friction does not depend on the frequency of vibration and the amplitude-independent one seems to be proportional to the frequency.