Symmetric stacking fault nodes in anisotropic crystals

Abstract

The equilibrium configurations of symmetric, 3-fold stacking fault nodes in f.c.c. crystals were determined by a linear elastic self-stress method which accounts for the combined effects of dislocation interaction and elastic anisotropy. Based on the results, a set of empirical equations was developed which compactly summarizes the solution to the anisotropic node problem, and which can be used to analyze node measurements. In principle, the stacking fault energy γ and the dislocation core radius r 0 can be obtained from node measurements; however, analysis of data for silver displayed too much scatter for both values to be reliably extracted, and a best fit value of γ = 23.5 erg/cm 2 was obtained with the assumption of r 0 = b. The appropriate choice of the Poisson ratio and shear modulus to obtain an isotropic approximation to the anisotropic node problem was given, and the deviations from isotropy in the node configurations were rationalized, qualitatively, in terms of the line tension of the partial dislocations.