On a thermoinertial mechanism for plasticity enhancement in metals during the transition from the normal to the superconducting state
Abstract
A method is proposed for taking account of the influence of the inertial properties of dislocations on the velocity of their thermally activated motion. This method is based on a statistical examination of the thermally activated motion of the dislocations through a random mesh of point obstacles. It is shown that the mean free path λ− of the dislocations after each act of thermal activation is not always equal to the mean spacing λ0¯ between adjacent obstacles and in the general case λ¯=λ¯(σ)≥λ¯0 Upon including the inertial properties of the dislocations, the ratio γ between the dynamic value of the angle at the beginning of each dislocation segment and the corresponding static value of this angle becomes greater than unity. Then it should be that λ¯=λ¯γ3/2σ. The change in the strain rate during the transition from the N- into the S -state, which occurs because of the effect of the thermoinertial mechanism, equals ϵ˙s/ϵ˙N=λ¯γs3/2σ/λ¯γN3/2σ and can reach several orders of magnitude.