A simulation of structure and motion of edge dislocations in ordered Ni3Al was performed by atomic stiffness matrix method. In this method the equilibrium positions of the atoms were obtained by solving a set of linear equations formed by a stiffness matrix, whose terms consisted of derivatives of the interaction potential of embedded atom method type. The super-partial dislocations, separated by an antiphase boundary on (111), dissociated into Shockley partials with complex stacking faults on (111) plane. The core structure, represented by the Burgers vector density distribution and iso-strain contours, changed under applied stresses as well as upon addition of boron. The separation between the super-partials changed with the addition of B and antisite Ni. As one Shockley partial moved out to the surface, a Shockley partial in the interior moved a large distance to join the lone one near the surface, leaving behind a long complex stacking fault strip. The decrease in the width of the antiphase boundary upon addition of B and antisite Ni was explained by a reduction of the strength of directional bonding between Ni and Al as well as by the dragging of B atmosphere by the super-partials.

Simulation of Dislocations in Ordered Ni3Al by Atomic Stiffness Matrix Method. Hsu, Y.E., Chaki, T.K.: Materials Research Society Symposium - Proceedings, 1996, 408, 249-54. See also: Materials Research Society Symposium - Proceedings, 1996, 409, 121-6