Effect of symmetrical and asymmetrical tilt grain boundaries on radiation-induced defects in zirconium

Abstract

In this article, molecular-dynamics-based simulations were used to study the effect of grain boundaries (GBs) on the formation and spatial distribution of radiation-induced point defects. In order to perform this study, two sets of symmetrical and asymmetrical tilt grain boundaries were constructed along [0 0 0 1] and [0 −1 1 0] as the tilt axis, respectively. Vacancy, interstitial and Frenkel pair formation energies were estimated as a function of the distance from the GB core for both symmetrical as well as asymmetrical tilt GBs. The trend obtained between GB energies and point defect formation energies helps explain the biased absorption of interstitials over vacancies in most cases, as well as the equal absorption of both kinds of point defects in a few of them. It has already been reported from the experimental work that [0 0 0 1] GB structures closely resemble the polycrystalline texture of hcp materials, which motivates us to study the effect of irradiation on these GBs.

Atomistic simulations to study the effect of Nb precipitate on fracture properties of bi-crystalline Zr

“…All grain boundary configu rations were formed along [0 0 0 1] as the tilt axis. Detailed steps involved in the generation of STGB were reported in our previous work [30,31]. Single phase substitutional Zr-Nb alloy was formed up to 0.7% Nb, whereas any further addi tion of Nb, precipitates at the GB and forms (αZr + βNb) two phase alloy, which was in congruence with the experimentally observed alloy structure [24,25].…”

“…Due to this, the GB energy of STGB with misorientation angle of 27.8° (E GB = 791.8) is higher than that of a lower angle, 13.2° (E GB = 756.37). The GB energy of atomic configurations was validated from previous work [30].…”

Radiation-induced defects in the InGaN/GaN superlattice structure

“…For the MD method, we utilized the software called Large-scale Atomic/Molecular Massively Parallel Simulator [19]. This software is suitable for simulating radiation-induced defects in materials [15][16][17][18]. The polymorphic potential [20] has been applied to the MD simulations because the polymorphic potential is suitable for multilayer structures and prescribes more realistic elastic constants than the conventional Stillinger-Weber potential [21].…”

“…To explain the microscopic mechanism of irradiated InGaN/GaN SLS, we rectified the simulation method of Shan et al [11] by combining the Monte Carlo simulation with the the molecular dynamics (MD) method. According to previous researches [15][16][17][18], the MD method is effective in simulating the process of defect recombination. This study focused on radiation-induced defects in the In 0.16 Ga 0.84 N/GaN SLS and the In 0.04 Ga 0.96 N/GaN SLS because these two kinds of structures have been applied to solar cells under irradiation [11].…”

A Comparison between ∑3 Asymmetrical Tilt Grain Boundary Energies in Niobium Obtained Analytically and through Molecular Dynamics Based Simulations

“…Literature of such work is limited on bcc crystals [7][8]. Recently, Divya and Avinash have studied the bicrystals of Niobium along [100] tilt axis [9] and that of Zr along [0001] and [0-110] axes [10][11][12][13][14]. In this article, ∑3 symmetrical and asymmetrical tilt grain boundaries of bcc niobium along [110] tilt axis is studied for their structure and energies through molecular dynamics (MD) based simulations.…”