In order to investigate the effect of impurities upon the mechanical properties of this intermetallic, the electronic structure and energy of material with a <100>{010} edge dislocation and transition-metal impurities was calculated by using the real-space tight-binding linear muffin-tin orbital method. The localized electronic states which appeared in the core of the dislocation were found to lead to strong impurity/dislocation interactions via 2 mechanisms. One was a chemical locking which was due to a strong hybridization between impurity electronic states and dislocation localized states. The other was an electrostatic locking which was due to long-range charge oscillations that were caused by electron localization in the dislocation core. The results explained qualitatively why solid-solution hardening in this material was related to the electronic structure of impurities rather than to the size misfit; as expected on the basis of the usual theories.

Electronic Mechanism of Impurity-Dislocation Interactions in Intermetallics - NiAl. O.Y.Kontsevoi, Y.N.Gornostyrev, A.J.Freeman, M.I.Katsnelson, A.V.Trefilov:

Philosophical Magazine Letters, 2001, 81[7], 455-63