Title: Abstract template EMMM-07
Author: EMMM-07
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Company: ВНИИНМ

Self-Point Defects Characteristics and Their Dependence on Stress Fields of Edge and Screw Basal Dislocations with Burgers vector 1/3 in HCP Zr

Dmitriy A. Chulkin^*, Viatcheslav M. Chernov, and Alexander B. Sivak

A.A. Bochvar Institute of Inorganic Materials, Moscow, Russia

PACS codes/keywords: 61.72.Lk, 61.72.Ji, 61.72.Yx /zirconium, self-point defects, dislocations, interactions, molecular statics, anisotropic theory of elasticity.

ABSTRACT

In hcp Zr crystal, the characteristics (formation and migration energies, relaxation volume and dipole tensor) of stable, metastable (including saddle point) configurations of self-point defects (SIA – self-intersitial atoms, vacancies) have been calculated by computer simulation methods with use of the many-body interaction potential [1]. The stress fields of the straight perfect edge and screw basal dislocations with Burgers vector 1/3 and the spatial dependence of the interaction energy between these fields and self-point defects (elastic dipoles) have been calculated using the anisotropic theory of elasticity.
The most energetically favorable SIA configuration in the attraction area of the edge dislocation is a basal crowdion (BC) oriented along the Burgers vector. Two minima of its formation energy in a given basal plane are located at the rays that make up the angles φ = 72.3° and φ = 107.7° with the slip plane (0001), and the local maximum is located at φ = 90°. The vacancy formation energy in a given basal plane is minimal at φ = 270°. The most favorable SIA configurations in the presence of the screw dislocation are BC with  and  orientations. Minima of their formation energy are located at the rays φ = 270° and φ = 90°, correspondingly. The interaction energy between the screw dislocation and the stable vacancy configuration is equal to zero.
To approach to the dislocations lying in a basal plane, self-point defects have to make jumps from a basal plane to another. The most favorable mechanism for the SIA approaching to the dislocations is a combination of out-of-basal plane jump and consequent in-basal plane reorientation. As the distance to the dislocations decreases, the corresponding energy barrier increases for the SIA and decreases for the vacancy in the stated above areas of minimal formation energy of the stable SIA and vacancy configurations.

[1]	G. J. Ackland, S. J. Wooding and D. J. Bacon, Defect, surface and displacement-threshold properties of α-zirconium simulated with a many-body potential, Philos. Mag. A 71 (1995) 553.

*Presenting author: Dmitry Chulkin
Postal address: 123060, P.O.Box 369, Moscow, Russia
Tel.: +(499)1903605; Fax.: +(499)1964168
E-mail: chernovv@bochvar.ru