Study on the superdislocation dissociation widths in L1₀ TiAl

The effects of anisotropic elasticity, superdislocation dissociation configurations, deformation temperatures as well as lamellar interfaces on the superdislocation dissociation widths have been studied. The calculation results showed that anisotropic elasticity made both the superdislocation dissociation widths and the difference between edge and screw superdislocation dissociation widths become smaller comparing with isotropic elasticity. The superdislocation dissociation widths of the superlattice intrinsic stacking fault (SISF) in the 3-fold or 4-fold dissociations were calculated to be smaller than that in 2-fold dissociation. The superdislocation dissociation widths were also affected by the non-coplanar dissociation configuration, the variation of which was with the Burgers vectors of dissociated superdislocations. The experimental results showed that deformation temperatures had little effect on the <101] superdislocation dissociation widths, implying that the shear modulus and stacking fault energy have the same changeable tender with temperatures. The dissociation widths of <101] superdislocations near the lamellar interfaces of γ/γ type were different with that inside the γ lamellar, the nearer the distance, the narrower the dissociation widths.