The effects of elastic anisotropy and dislocation configuration on the superdislocation dissociation widths in TiAl

Abstract

Theoretical calculation of the dissociation widths of\(\langle 10\bar 1]\) and\(1/2\langle 11\bar 2]\) superdislocations with different orientations and configurations have been carried out under the equilibrium condition that the total elastic interaction force acting on partial dislocations is balanced by the fault surface tension acting in the opposite direction. The results show that the superdislocation dissociation widths depended not only on stacking fault energies and dislocation characteristics but also on elastic anisotropy, superdislocation types and dissociation modes. Under the elastic anisotropy, the dissociation width of screw\(1/2\langle 11\bar 2]\) superdislocation is larger than that of screw\(\langle 10\bar 1]\) superdislocation, and the dissociation width of edged\(1/2\langle 11\bar 2]\) superdislocation is smaller than that of edged\(\langle 10\bar 1]\) superdislocation with the same stacking fault energy. The dissociation widths under the twofold, threefold and fourfold dissociations are also evaluated with anisotropy. The present results help to determine the stacking fault energies and evaluate the mobility of superdislocation in TiAl.