THE ELASTIC INTERACTION ENERGY OF DISLOCATION LOOPS IN ANISOTROPIC MEDIA

Irradiation of metals leads to the formation of point-defects (vacancies and selfinterstitials) that usually agglomerate in the form of dislocation loops. Due to the elastic interaction between SIA (self-interstitial atoms) and dislocations, the loops absorb in most cases more SIA than vacancies. That is why the loops observed by transmission electron microscopy are almost always interstitial in nature. Nevertheless, vacancy loops have been observed in zirconium following electron or neutron irradiation (see for example [1]). Some authors proposed that this unexpected behavior could be accounted for by SIA diffusion anisotropy [2]. Following the approach proposed by Woo [2], the cluster dynamics model presented in [3] that describes point defect agglomeration was extended to the case where SIA diffusion is anisotropic. The model was then applied to the loop microstructure evolution of a zirconium thin foil irradiated with electrons in a high-voltage microscope. The main result is that, due to anisotropic SIA diffusion, the crystallographic orientation of the foil has considerable influence on the nature (vacancy or interstitial) of the loops that form during irradiation.

Download Full-text

Elastic Interaction of Defects on Crystal Surfaces

Journal of Engineering Materials and Technology ◽

10.1115/1.2812357 ◽

1999 ◽

Vol 121 (2) ◽

pp. 129-135 ◽

Cited By ~ 8

Author(s):

Demitris Kouris ◽

Alonso Peralta ◽

Karl Sieradzki

Keyword(s):

Interaction Energy ◽

Surface Defects ◽

Film Growth ◽

Crystal Surface ◽

Elastic Field ◽

Elastic Interaction ◽

Flow Mode ◽

Elastic Model ◽

Far Field ◽

Embedded Atom

Surface defects corresponding to adatoms, vacancies and steps interact, affecting and often dominating kinetic processes associated with thin-film growth. A discrete harmonic model for the evaluation of the interaction energy between surface defects is presented. It is based on the concept of eigenstrains and allows for the accurate evaluation of the elastic field, both at the immediate vicinity of the defects, as well as in the far field. Results for the interaction energy suggest conditions for which a body-centered-cubic crystal surface will grow in a stable, two-dimensional, step-flow mode. In order to verify the accuracy of the discrete elastic model, we present results of atomic simulations that incorporate Embedded Atom Method (EAM) potentials. The discrete elastic model results compare favorably with results from our atomic EAM simulations and agree with the far-field predictions of continuum elastic theory.

Download Full-text

Line Integral Expressions of Interaction Energy of Dislocation Loops in Anisotropic Materials

Journal of Applied Physics ◽

10.1063/1.1657105 ◽

1969 ◽

Vol 40 (1) ◽

pp. 73-75 ◽

Cited By ~ 2

Author(s):

T. Mura

Keyword(s):

Interaction Energy ◽

Anisotropic Materials ◽

Dislocation Loops ◽

Line Integral

Download Full-text

The effect of elastic interaction energy on the morphology of γ′precipitates in nickel-based alloys

Materials Science and Engineering ◽

10.1016/0025-5416(84)90056-9 ◽

1984 ◽

Vol 67 (2) ◽

pp. 247-253 ◽

Cited By ~ 125

Author(s):

Minoru Doi ◽

Toru Miyazaki ◽

Teruyuki Wakatsuki

Keyword(s):

Interaction Energy ◽

Elastic Interaction

Download Full-text

Perovskite Ti3AlC Carbide Splitting in High Nb Containing TiAl Alloys

MRS Proceedings ◽

10.1557/opl.2014.950 ◽

2014 ◽

Vol 1760 ◽

Cited By ~ 1

Author(s):

Li Wang ◽

Heike Gabrisch ◽

Uwe Lorenz ◽

Frank-Peter Schimansky ◽

Andreas Stark ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Interaction Energy ◽

Elastic Interaction ◽

Morphological Development ◽

Tial Alloys ◽

Transmission Electron ◽

The Matrix

ABSTRACTTransmission electron microscopy has been used to investigate the morphological development of the perovskite (P-) Ti3AlC carbides in the γ matrix of a Ti-45Al-5Nb-0.75C alloy during annealing. P-Ti3AlC carbides in the γ matrix initially have a needle-like shape but during annealing at 800 °C they change to a plate-like shape. In the needle-like shape the carbides are orientated parallel to the [001] direction of the matrix. They extend along the [100]γ or [010]γ direction into plates later and subsequently split into sub particles after extended annealing. It is proposed that the elastic interaction energy between the split sub domains may be the reason that this decomposition into sub-particles is energetically favorable.

Download Full-text