The elastic interaction of divacancies and extended dislocations in F.C.C. metals

The energies and the forces resulting from the interaction of dislocations having orientations ranging from pure screw to pure edge and divacancies existing along the various 〈110〉 directions in f.c.c. metals have been computed. The interaction energy is maximum when the divacancy is along the Burgers vector of a perfect dislocation in purely edge orientation. The maximum interaction force occurs when the divacancy exists along a direction perpendicular to the Burgers vector of a perfect edge dislocation. Splitting of a dislocation even to a small extent (by a few atomic distances) significantly lowers the interaction energy and the interaction force. The computed energy values were used to estimate the maximum binding energy between a divacancy and a dislocation, a divacancy and a tetrahedral stacking fault, and the hardening coefficient. The estimated values of these were compared with experimental results obtained in as-quenched gold.