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.
The kinetics of the jump-like process of creep strain increase during the crystal transition from the normal t o the superconducting state was studied. It is shown that the crystal transition from the N (normal) to the S (superconducting) state in the creep process is characterized by a certain delay time during which the creep rate remains constant after the transition to the S state. The delay time dependence on temperature and stress was studied. The delay time decreased exponentially with the increase of stress on the crystal at the normal state and displays a sharp decrease with the lowering of temperature. The obtained results are accounted for on the basis of the model of a thermally activated unpinning of dislocations from obstacles taking into consideration the peculiarities of the model in the low-temperature region. M~aysaxac~ mmenma npouecca c~a s~o o B p a 3~o r o npkIpameHm Ae#opMaIzw n o m y~e c~~x npH nepexone KpHcTama 1.13 HopManbHoro B csepxnpoBozmqee comomme. n o~a 3 a~0 , YTO nepexon HpticTanna 113 N B S CocTommie B npogecce IIOJI3yseCT11 XapZiKTepH3YeTCX HeKOTOPbIM BpeMeHeM 3aDepXWWi, B TeVeHHe ICOTO-pOr0 CKOpOCTh IlOJl3yseCTH nOCJIe IlepeXODa B S COCTOfIHHe OCTaeTCR HeH3MeHHOa. MCCJIeAOBaHa 3aBHCHMOCTb BpeMeHH 3aAepXKH OT TeMnepaTypbl H HaIlpHXeHMH. HpeMR 3anepmHI.i 3KCIIOHeH4HaJIbHO CllaRaeT C POCTOM BeJIH9LIHbI
The influence is considered of the deformational hardening of metals at its different stages on the creep strain jump Δϵns during the n–s transition. The curves representing the strain dependence of the jump Δϵns are shown to have a phase nature. Their different phases correlate with the stages of the hardening curves. This relation is determined by a strong dependence of the jump magnitude Δϵns on hardening coefficient of the metal and the activation volume. The complex behaviour of the Δϵns(ϵ) dependence observed at different stages of the hardening curve can be explained by a non‐monotonic variation of the hardening coefficient along theτ‐ϵ curve. The experimental results obtained are in a good qualitative agreement with the conclusions of the theory of enhanced plasticity at the n–s transition assuming thermal‐activated unpinning.
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