It was noted that rate laws of Becker type were inappropriate for dislocations. They had been developed for treating independent particles, and not for lines where the motions were highly correlated. Because one end of a line could not communicate with the other end faster than the speed of sound, there were correlation problems when the activation area considered was larger than a few atomic squares. For example, there were difficulties with conventional kink-nucleation theory. Without arbitrary modification, this theory did not satisfactorily describe the observed temperature dependence of the flow stresses. It was shown that the intrinsically 1-dimensional Becker-type theory could be combined with a 2-dimensional theory so as to yield a physically consistent model that provided a better description of the temperature dependence of plastic flow stresses without being arbitrary.

Toward Physically-Based Rate Laws for Dislocations. J.J.Gilman: Materials Science and Engineering A, 2002, 322[1-2], 126-131