Index of content:
Volume 32, Issue 12, December 2006
- LOW-TEMPERATURE PHYSICS OF PLASTICITY AND STRENGTH
Quantum creep of in the normal and superconducting states. Influence of the NS transition on work hardening32(2006); http://dx.doi.org/10.1063/1.2400699View Description Hide Description
Previously we investigated the kinetics of transient logarithmic creep of –tin single crystals at very low temperatures with the sample under deformation in the normal (N) electronic state. In a continuation of that research, here we determine the boundary temperature separating the regions of thermally activated and quantum plasticity governed by the motion of dislocations through Peierls barriers. Experiments are done on samples in the superconducting (S) state . It is shown that the NS transition preserves the logarithmic type of creep, its quantum character in the region , and the value of the boundary temperature . Analysis of the curves of the logarithmic creep in the quantum region can yield empirical estimates for the work hardening coefficient of the samples. It is found to increase significantly at the NS transition: along the whole deformation curve the work hardening in the state occurs more intensely, and, on the average, . Such an effect has been observed previously in a study of the plasticity of a series of fcc metals by the method of active deformation at a constant rate (V. V. Pustovalov, I. N. Kuz’menko, N. V. Isaev, V. S. Fomenko, S. É. Shumlin, Fiz. Nizk. Temp.30, 109 (2004) [Low Temp. Phys.30, 82 (2004)]). A comparison of the results of this study with previous results suggests that the increase in intensity of the work hardening at the superconducting transition is of a general nature for metallic superconductors and is manifested for other deformation regimes as well. The possible causes of the effect are discussed in the general conceptual framework of dislocation physics.