Nonlinear Effects for Defects in Solids
Professor John Hirth
Washington State University
Department of Mechanical & Materials Eng.
Pullman, WA 99164-2920
(509) 335-8654
(509) 335-4662 FAX
Point defects (vacancies, interstitials, solute atoms), line defects (dislocations, disconnections, disclinations), and interface defects (grain boundaries, twin boundaries, interphase interfaces) all have nonlinear fields. Examples are the elastic fields and electrostatic fields (particularly for ionic materials) near the defect cores. Kinks and jogs also represent point defects residing on line defects and dislocations, for example, represent line defects in an interface. These defects have highly nonlinear fields. All of these nonlinear fields have been treated to some extent by perturbation theory. However, only now is a general nonlinear theory being developed.
The information needed for such a theory can be supplied by atomistic computer simulations. The simulations can now be run with 106-107 atoms. Moreover, boundary condition methods are becoming more sophisticated. Thus, calculations should give significant new results in the next few years.