TY - JOUR

T1 - Understanding why dislocation loops are visible in Transmission Electron Microscopy: The Tungsten Case

AU - Castin, Nicolas

AU - Bakaev, Alexander

AU - Terentyev, Dmitry

AU - Pascuet, Maria Ines

AU - Bonny, Giovanni

N1 - Score=10

PY - 2021/6/8

Y1 - 2021/6/8

N2 - Dislocation loops finely disperse in bulk W are generally visible to the transition electron microscopy (TEM) after irradiation. In the absence of strong interactions, these loops would normally diffuse very fast until being sunk at grain boundaries or at the dislocation network. In this work, we evaluate the strength of two pining effects that can explain the reason why they are nevertheless observed by TEM in bulk. On the one hand, we evaluate with density functional theory (DFT) the strength of binding between isolated loops and dissolved chemical impurities. Employing classical equations of diffusion, we estimate the resulting effective diffusion coefficient of loops. On the other hand, we consider the effect of mutual elastic interactions (MEI) between the loops, applying linear elasticity. We perform a large set of kinetic Monte Carlo (KMC) simulations, aimed at evaluating the effective diffusion coefficient, accounting for multiple interactions. Finally, we draw a map under which experimental condition (loop size and loop number density) what is the dominating pinning effect. Comparing with a large database of experimental TEM evidence, we conclude that pinning by dissolved impurities is the dominating effect.

AB - Dislocation loops finely disperse in bulk W are generally visible to the transition electron microscopy (TEM) after irradiation. In the absence of strong interactions, these loops would normally diffuse very fast until being sunk at grain boundaries or at the dislocation network. In this work, we evaluate the strength of two pining effects that can explain the reason why they are nevertheless observed by TEM in bulk. On the one hand, we evaluate with density functional theory (DFT) the strength of binding between isolated loops and dissolved chemical impurities. Employing classical equations of diffusion, we estimate the resulting effective diffusion coefficient of loops. On the other hand, we consider the effect of mutual elastic interactions (MEI) between the loops, applying linear elasticity. We perform a large set of kinetic Monte Carlo (KMC) simulations, aimed at evaluating the effective diffusion coefficient, accounting for multiple interactions. Finally, we draw a map under which experimental condition (loop size and loop number density) what is the dominating pinning effect. Comparing with a large database of experimental TEM evidence, we conclude that pinning by dissolved impurities is the dominating effect.

KW - Kinetic Monte Carlo

KW - Transition electron microscopy

KW - Radiation effects

KW - Dislocation loops

UR - https://ecm.sckcen.be/OTCS/llisapi.dll?func=ll&objId=44973648&objAction=download

U2 - 10.1016/j.jnucmat.2021.153122

DO - 10.1016/j.jnucmat.2021.153122

M3 - Article

VL - 555

SP - 1

EP - 9

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

SN - 0022-3115

M1 - 153122

ER -