Self-immobilization of superdislocations in L1(2) alloys: a simple statistical analysis

A simple statistical analysis of the structure or superdislocations in Ll(2 ) compounds displaying the yield strength anomaly is developed. This analys is is based on the superkink model of dislocation dynamics, where it is ass umed that a superdislocation propagates through the lateral motion of super kinks. The analysis is used to assess the probability that a superdislocati on is immobile, and this probability is found to depend exponentially on th e nominal length of the superdislocation. The statistical analysis requires knowledge of the global distribution of superkink lengths to obtain quanti tative relative immobilization rates; this information is extracted;from pu blished experimental work and also from previous simulations. The implicati ons of both superkink distributions are explored. The predictions of the an alysis appear consistent with the results from simulations.