MOLECULAR STATICS SIMULATIONS OF CORE STRUCTURES AND MOTION OF DISLOCATIONS IN NIAL

Possible dislocation core structures in NiAl were studied using molecular statics calculations with an empirical many-body interatomic potential developed specifically for NiAl within the embedded-atom method. The cores were examined under stress, and the stress required to initiate motion was used to estimate the relative mobility of the dislocations. Dislocations with Burgers vectors of a[001], a[110] and a[111] and of edge, screw and mixed characters were studied. The glide planes examined included the {110}, {112} and {100} planes. The results were compared with reported experimental observations and the simulation results were found to be in good agreement and/or consistent with most experimental observations to date. The results suggest that atomic simulations may offer a significant advantage over the continuum models in inderstanding the slip response of NiAl.