부산대학교 도서관

The creep of β-Sn single crystals oriented for slip in the (100)<010> system is investigated in the temperature range 0.45–4.2 K. A transient creep, decaying in time by a logarithmic law, is registered both above and below 1 K. The temperature dependence of the coefficient of logarithmic creep is studied in detail, and the existence of two qualitatively different regions of its behavior is established: in the interval 4.2–1.2 K the coefficient increases linearly with decreasing temperature, while below 1 K the creep acquires an athermal character and the coefficient remains constant. It is shown that the regularities observed in the experiment are in accord with the idea that the kinetics of creep in pure β-Sn is governed by the motion of dislocations in the Peierls potential relief by a mechanism of nucleation of kink pairs on the dislocation lines. This process entails the overcoming of a small effective potential barrier of the order of 0.001 eV: in the temperature region T<1 K the nucleation of kink pairs occurs by a quantum tunneling effect, and the creep is of a purely quantum character; at higher temperatures the leading role is played by thermal fluctuations, and the deformation kinetics corresponds to the classical ideas of thermally activated creep. Empirical estimates are obtained for the density of mobile dislocations and the work hardening coefficient. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]