Low-temperature strain aging in In–Pb alloys under conditions of stress relaxation

In the stress-relaxation regime the dynamic strain aging (DSA) in single crystals of the substitutional solid solutions of substitution In–Pb with 6 and 8 at. % Pb is investigated at temperatures of 77–205 K. It is determined how the DSA-related post-relaxation hardening depends on the duration of the stress relaxation, the rate of change of the stress at the end of the relaxation, the temperature, the concentration of the alloy, the flow stress, and the degree of deformation. It is shown that the DSA kinetics is described by an equation of the Harper type with an exponent of 1/3 and a low value of the activation energy for the process (0.3–0.34 eV), which makes for a low temperature for the onset of DSA $(∼0.17 Tm,$ where $Tm$ is the melting temperature) and is indicative of a pipe character of the diffusion. It is assumed that the obstacles to the motion of dislocations in these crystals are impurity complexes, the strength of which increases during DSA as a result of the pipe diffusion of impurity atoms along dislocations.