scholarly journals ELASTIC INTERACTION ENERGY OF POINT DEFECTS WITH A BASAL DISLOCATION LOOP IN ZIRCONIUM

2020 ◽  
pp. 84-90
Author(s):  
O.G. Trotsenko ◽  
A.V. Babich
Keyword(s):  
Interaction Energy ◽  
Dislocation Loop ◽  
Point Defects ◽  
Elastic Interaction ◽  
Basal Dislocation

scholarly journals BIAS OF BASAL DISLOCATION LOOP IN ZIRCONIUM

2021 ◽  
pp. 29-34
Author(s):  
A.V. Babich ◽  
P.N. Ostapchuk
Keyword(s):  
Numerical Calculation ◽  
Dislocation Loop ◽  
Point Defects ◽  
Function Method ◽  
Elastic Field ◽  
Its Region ◽  
Elastic Interaction ◽  
Basal Dislocation ◽  
Hexagonal Crystals ◽  
Toroidal Geometry

An analytical expression for the elastic interaction energy of radiation point defects of the dipole type with the basal dislocation loop of the hcp metal is obtained using the Green's function method for hexagonal crystals in the Krener approach. It was used for numerical calculation of the bias for the basal dislocation loop of zirconium in a toroidal reservoir. The toroidal geometry of the reservoir allows one to perform the calculation for a loop of any size and without any correction of the elastic field in its region of influence. The dependencies of the loop bias on its radius and nature are obtained for various shapes of dipole defects.

The stress-driven migration of point defects to a crack

1985 ◽  
Vol 397 (1812) ◽  
pp. 121-141 ◽  
Keyword(s):  
Steady State ◽  
Stress Field ◽  
Interaction Energy ◽  
Point Defects ◽  
Elastic Interaction ◽  
Constant Concentration ◽  
Nearby Point ◽  
Loaded Crack ◽  
Solute Atoms ◽  
Kinetics Of

The elastic interaction energy between a crack tip and nearby point defects is derived and used to estimate the kinetics of migration of these defects in the stress field of a loaded crack. Explicit results are obtained for both the transient depletion of solute atoms from an initial constant concentration and the steady state loss of point defects to a crack during irradiation. In the latter situation the migrating defects can be either self-interstitials or vacancies, and attention is drawn to the fact that interstitials should be lost at the tip of the crack whereas vacancies should enter the crack across the surfaces behind the actual tip.

Effect of Self-Interstitial Diffusion Anisotropy in Electron-Irradiated Zirconium. A Cluster Dynamics Modeling

2005 ◽  
Vol 237-240 ◽  
pp. 659-664
Author(s):  
Frédéric Christien ◽  
Alain Barbu
Keyword(s):  
Point Defects ◽  
Thin Foil ◽  
Elastic Interaction ◽  
Dislocation Loops ◽  
Considerable Influence ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Diffusion Anisotropy ◽  
Vacancy Loops ◽  
Transmission Electron

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.

Elastic Interaction of Defects on Crystal Surfaces

1999 ◽  
Vol 121 (2) ◽  
pp. 129-135 ◽  
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.

Perovskite Ti3AlC Carbide Splitting in High Nb Containing TiAl Alloys

2014 ◽  
Vol 1760 ◽  
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.

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