The influence of elastic anisotropy on interaction of dislocations with point defects in BCC metals

Abstract

Dedicated t o l'rofessor V. I. STARTSEV on the occasion of his 70th birthdayWith the use of the anisotropic theory of elasticity the energies and the force-distance profiles for the interaction of vaIious types of straight dislocations with point defects of intrusion (atoms of N, C or 0) and of replacement in RCC metals with a different degree of elastic anisotropy (Nb, V, Ta, a-Fe) have been calculated. The calculated force-distance profiles in most cases are not centrally symmetric, t h a t leads up t o a gliding asymmetry at the direct and reverse directions of dislocation motion. The crystal elastic anisotropy can change the relative mobility of dislocations of various types and accounts for a number of experimentally observed peculiarities of RCC metals stress-strain properties.Mittels der anisotropen Elastizitatstheorie wurden die Energien und Kraft-AbstandsProfile fur die Wechselwirkung verschiedener Typen von geraden Verzetzurigen mit intrusiven Punktdefekten (N-, C-, 0-Atomen) und des Ersatzes in krz-Metallen mit unterschiedlichem Grad der elastischen Anisotropie (Nb, V, Ta, a-Fe) berechnet. Die berechneten Kraft-Abstands-Profile sind in den meisten Fallen nicht zentral-symmetriseh; dies fuhrt zu einer Gleitasymmetrie in der Hin-und Herrichtung der Versetzungsbewegung. Die elastische Kristallanisotropie kann die relative Heweglichkeit der Versetzungen unterschiedlichen Typs andern und ist fiir mehrere experimentell beobachtetc Resonderheiten der Spannungs-Dehnungseigenschaften der krz-Metalle verantwortlich.

Influence of stress fields of dislocations on formation and spatial stability of point defects (elastic dipoles) in V and Fe crystals

“…The interaction energy E int within the framework of the theory of elasticity is given by [3,[5][6][7][8][9] …”

“…Computer simulation methods (for calculation of point defects characteristics in crystals without dislocations) and the linear anisotropic theory of elasticity (for calculations of elastic fields of dislocations and their interactions with point defects) were used both for calculations of interaction of point defects with dislocations [3,[5][6][7][8][9]]. …”