Temperature dependence and activation parameters of creep in Zn in the temperature range 1.5 to 80 °K

Abstract

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.

Low-temperature creep in pure metals and alloys

“…Early proponents included [20,24,26,27]. Conversely, subsequent work by [13,22,23] suggests that, even to 4 K, creep is time-dependent and is a result of the thermal activation of dislocations.…”

“…Seeger et al [19,33,34] proposed a dislocation intersection mechanism for pure FCC metals under polyslip. Others have suggested that creep occurs due to quantum mechanical tunneling of dislocations at very low temperature [13,20,22,24,26,27], but there is no consensus as to the actual mechanisms involved.…”

“…However, some materials do demonstrate significant creep at T \ 0.3T m and, furthermore, at stresses both above and below the macroscopic yield stress (r 0:002 y ). These materials include Ti-alloys and steels [1][2][3][4][5][6][7][8][9][10], Al-Mg [11], a-Brass [12], ionic solids [13], pure Au, Cd, Cu, Al, Ti, Hg, Ta, Pb, Zn [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], and precipitation hardened alloys [29] (as well as glass and rubber [28]). Materials may undergo plasticity that affects its intended (e.g., structural and electrical [30][31][32]) performance.…”

Review on Creep Analysis and Solved Problems

“…Exceptional reviews of the widespread studies on the topic may be found in some important references [80][81][82]. Also, some studies were done regarding the proposition of quantum mechanical tunneling of dislocations at very low temperature [83][84][85][86][87][88].…”

Precision measurements of plastic deformation of β‐CuZn at helium temperatures

“…NATSIK et al (1972; 1979) proposed a theory in which the zero-point vibration of dislocation segments influences the surmounting process of the dislocation over a point barrier, and explained anomalous creep behaviour of various metals a t helium temperatures which was reported by the school of STARTSEV (NATSIK et al 1972;OSETSKII et al;1974a, b ;KOVAL et al). The inertial effect (GRANATO; SUENAGA et al) and the zipper effect (LANDAU 1973(LANDAU , 1975 have also been considered to be responsible for the low temperature anomaly of soft metals.…”