Effect of elastic anisotropy on the dissociation widths of superdislocations in TiAl.pdf

April 2001 Materials Letters 48 Ž2001. 273–280 rlocatermatlet Effect of elastic anisotropy on the dissociation widths of superdislocations in TiAl X.P. Song ), G.L. Chen State Key Laboratory for AdÕanced Metals and Materials, UniÕersity of Science and Technology Beijing, Beijing, 100083, People’s Republic of China Received 20 July 2000; accepted 10 September 2000 Abstract ² x ² x The dissociation widths of the 101 and 1r2 112 superdislocations in TiAl have been calculated by the elasticity theory that the elastic interaction energies and stacking fault energies acting on the partial dislocations are equal. The results show ² x ² x that the dissociation widths of the screw 101 and 1r2 112 superdislocations in anisotropic condition are smaller than that ² x ² x of isotropic condition, but the dissociation widths of the edge 101 and 1r2 112 superdislocations in anisotropic condition are larger than or equal to that of isotropic condition. The equilibrium separations of the superlattice intrinsic stacking fault Ž . ² x ² x SISF formed by the two-fold 101 and 1r2 112 superdislocation dissociations are nearly the same with each other in the elastic isotropy condition but are different in the elastic anisotropy condition. The stacking fault energy of SISF in a high-