ISSN:
1573-8205
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Physics
Notes:
Abstract The increase in the internal friction with time in heating at different rates was measured with respect to the damping of torsional vibrations during the heating of specimens. Specimens of γ-phase quenched, γ- and α-phase annealed, and recrystallized polycrystalline uranium were investigated. It is shown that the rate of the internal friction rise in specimens gradually decreases in time and that the internal friction increment attains a limiting value, the magnitude of which is approximately proportional to the specimen heating rate. The internal friction increment is related to stresses which arise in the specimen due to the anisotropic thermal expansion coefficient when the temperature changes. The reduction in internal stresses, which is either due to an increase in the grain size to a magnitude comparable to the diameter of the specimen under investigation or the formation of a predominant orientation in specimens, results in a reduction of the internal friction increment. During the heating process, also macroscopic shearing deformation occurs in the specimen. Such an increase in internal friction in heating was also observed in a thermally anisotropic metal, such as zinc; it was not observed in metals with isotropic thermal expansion coefficients — aluminum and molybdenum.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01483427
Permalink