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.

The effect of the superconducting transition on the velocity of creep in lead has been investigated and found to increase sharply a t the transition to the superconducting state. The value of the jump of creep velocity depends on the sample purity. The magnetic field does not effect the creep velocity. The possible causes (change of interaction between electrons and dislocations, change of barriers determining the mobility of dislocations at the superconducting transition) of the effect observed are discussed. E s wurde der EinfluB von Supraleitungsiibergangen auf die Kriechgeschwindigkeit in Blei untersucht und gefunden, daO diese am ubergang in den supraleitenden Zustand steil ansteigt. Der Wert des Sprunges der Kriechgeschwindigkeit hingt von der Reinheit der Probe ab ; das Magnetfeld beeinfluDt die Kriechgeschwindigkeit nicht. Die moglichen Grunde fur den beobachteten Effekt (dnderung der Wechselwirkung zwischen Elektronen und Versetzungen, dnderung der Barrieren, die die Geschwindigkeit der Versetzungen a m Supraleitnngsubergang bestimmen) werden diskutiert.

Data necessary to determine the activation energy and volume of the creep process in zinc have been obtained in the temperature range 1.5 to 80 °K by means of a differential technique. While calculating the activation parameters the influence of quantum phenomena on fluctuation‐induced dislocation motion over local barriers of the crystal lattice were taken into account. The analysis of the dependences of the activation parameters on temperature and effective stress shows that below a certain characteristic temperature θ, which for zinc is equal to 26 °K, the activation parameters should be calculated using quantum formulas, whereas for T > θ they may be calculated using conventional classical formulas. The obtained values of the activation parameters and their temperature dependences form a basis used to make conclusions about the nature of obstacles controlling the low‐temperature creep in Zn.

The temperature dependence of the creep rate jump in single crystals of cadmium and zink during temperature increment is studied in the range of 1.5 to 80 K. Also studied is the creep jump behaviour δϵNS during the N–S transition in pure lead, in alloys with abnormal heat conductivity, as well as lead alloys with paramagnetic admixture of nickel. It is shown that the observed peculiarities of the low temperature creep of metals are at sharp variance with the local thermal heating hypothesis. Experimental data obtained agree satisfactorily with the quantum theory of low temperature plastic deformation.