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Stress Induced Anisotropic Diffusion of Intrinsic Point Defects towards Dislocations in H.C.P. Crystals
Author(s) -
yDe Grande N. Smetniansk,
Savino E. J.,
Tomé C. N.
Publication year - 1987
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221440125
Subject(s) - materials science , vacancy defect , anisotropy , condensed matter physics , crystallographic defect , stress field , dislocation , lattice (music) , crystal (programming language) , thermodynamics , physics , optics , finite element method , computer science , acoustics , programming language
The diffusion equations for vacancies and interstitials in the field of straight edge dislocations are numerically solved for a crystal under irradiation and uniaxially stress. The main dislocation systems in hexagonal closed packed metals are considered. The diffusion model takes into account the full lattice and defect symmetry in the equilibrium and migration configurations. A diffusivity tensor for strained h.c.p. metals is deduced, which depends linearly on the strain field. This tensor allows to solve analytically the steady state defect flux towards a hollow cylinder in a homogeneously strained crystal. The resulting vacancy and interstitial absorption (sink strength) are calculated and compared with the ones obtained numerically when the dislocation field is taken into account. It is shown that both approaches result in a similar dependence of the sink strengths on the homogeneous strain as far as a correct capture radius is adopted for the hollow cylinder. The dependence of the results on the boundary conditions and the defect symmetry considered is discussed. For the numerical calculations defect symmetries consistent with those calculated for magnesium are used.