Peierls-Barrier Minima

Abstract

Several authors predict minima in the Peierls energy barrier to the motion of a dislocation when the barrier is considered as a function of the elastic or force-law parameters of a crystal. The present paper reports a numerical calculation of the Peierls barrier in the Frenkel—Kontorova dislocation model modified to include the second harmonic of the force substrate. For the elastic constants of polycrystalline copper, the model predicts Peierls-barrier minima, at stacking-fault energies of 660, 530, 360, 210, 120, 62, 32,…erg/cm2, which range approximately from 10−5 to 10−2 times the intervening barrier maxima of about 2.5×10−9 erg/cm. This prediction is more accessible to experimental test since the stacking-fault energy of copper can be modified by alloying with silicon. The Peierls barrier can be determined according to the Seeger interpretation of the Bordoni experiment.