Effect of impurity and alloying elements on Zr grain boundary strength from first-principles computations

Christensen, Mikael; Angeliu, Thomas M.; Ballard, Jake D.; Vollmer, James; Najafabadi, R.; Wimmer, E.

doi:10.1016/j.jnucmat.2010.07.012

Cited by 51 publications

(24 citation statements)

References 26 publications

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“…The segregation energies of the solute and impurities in Zr were estimated by first-principle calculation studies, which showed that Fe and Cr tend to segregate at the grain boundaries [24,25].…”

Section: Introductionmentioning

confidence: 99%

Microstructural analysis of impurity segregation around β-Nb precipitates in Zr–Nb alloy using positron annihilation spectroscopy and atom probe tomography

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Microstructural analysis of impurity segregation around β-Nb precipitates in Zr–Nb alloy using positron annihilation spectroscopy and atom probe tomography

et al. 2015

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“…These metals exhibit a drastic loss of ductility in the presence of certain liquid-metals, such as gallium (Ga), bismuth (Bi), and mercury (Hg) [1][2][3][4][5][6][7][8][9][10]. Understanding the mechanisms behind LME has been of particular interest in both experimental [2,3,5,8,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and simulation [7,9,[26][27][28][29][30][31][32][33] research.…”

Section: Introductionmentioning

confidence: 99%

Atomic-scale analysis of liquid-gallium embrittlement of aluminum grain boundaries

et al. 2014

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Material strengthening and embrittlement are controlled by intrinsic interactions between defects, such as grain boundaries (GB), and impurity atoms that alter the observed deformation and failure mechanisms in metals. In this work, we explore the role of atomistic-scale energetics on liquid-metal embrittlement of aluminum (Al) due to gallium (Ga). Ab initio and molecular mechanics were employed to probe the formation/binding energies of vacancies and segregation energies of Ga for <100>, <110> and <111> symmetric tilt grain boundaries (STGBs) in Al. We found that the GB local arrangements and resulting structural units have a significant influence on the magnitude of vacancy binding energies. For example, the mean vacancy binding energy for <100>, <110>, and <111> STGBs at 1 st layer was found to be -0.63 eV, -0.26 eV, and -0.60 eV. However, some GBs exhibited vacancy binding energies closer to bulk values, indicating interfaces with zero sink strength, i.e., these GBs may not provide effective pathways for vacancy diffusion. The results from the present work showed that the GB structure and the associated free volume also play significant roles in Ga segregation and the subsequent embrittlement of Al. The Ga mean segregation energy for <100>, <110> and <111> STGBs at 1 st layer was found to be -0.23 eV, -0.12 eV and -0.24 eV, respectively, suggesting a stronger correlation between the GB structural unit, its free volume, and segregation behavior. Furthermore, as the GB free volume increased, the difference in segregation energies between the 1 st layer and the 0 th layer increased. Thus, the GB character and free volume provide an important key to understanding the degree of anisotropy in various systems. The overall characteristic Ga absorption length scale was found to be about ~10, 8, and 12 layers for <100>, <110>, and <111> STGBs, respectively. Also, a few GBs of different tilt axes with relatively high segregation energies (between 0 and -0.1 eV) at the boundary were also found. This finding provides a new atomistic perspective to the GB engineering of materials with smart GB networks to mitigate or control LME and more general embrittlement phenomena in alloys.

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“…However, recent studies have shown that the size effect [11,35], and also changes in the bond order [17], may have a decisive influence on behavior of solutes at GBs. First principles calculations provide the most reliable information about the GB structure, energetics, and solute-GB interactions [11,12,[35][36][37][38][39][40][41][42]. However, they require advanced computational resources, and mostly special type (ST) GBs can be studied.…”

Section: Introductionmentioning

confidence: 99%

Alloying Element Segregation and Grain Boundary Reconstruction, Atomistic Modeling

Карькина

Kar’kin

Кузнецов

et al. 2019

Metals

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Grain boundary (GB) segregation is an important phenomenon that affects many physical properties, as well as microstructure of polycrystals. The segregation of solute atoms on GBs and its effect on GB structure in Al were investigated using two approaches: First principles total energy calculations and the finite temperature large-scale atomistic modeling within hybrid MD/MC approach comprising molecular dynamics and Monte Carlo simulations. We show that the character of chemical bonding is essential in the solute–GB interaction, and that formation of directed quasi-covalent bonds between Si and Zn solutes and neighboring Al atoms causes a significant reconstruction of the GB structure involving a GB shear-migration coupling. For the solutes that are acceptors of electrons in the Al matrix and have a bigger atomic size (such as Mg), the preferred position is determined by the presence of extra volume at the GB and/or reduced number of the nearest neighbors; in this case, the symmetric GB keeps its structure. By using MD/MC approach, we found that GBs undergo significant structural reconstruction during segregation, which can involve the formation of single- or double-layer segregations, GB splitting, and coupled shear-migration, depending on the details of interatomic interactions.

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Effect of impurity and alloying elements on Zr grain boundary strength from first-principles computations

Cited by 51 publications

References 26 publications

Microstructural analysis of impurity segregation around β-Nb precipitates in Zr–Nb alloy using positron annihilation spectroscopy and atom probe tomography

Microstructural analysis of impurity segregation around β-Nb precipitates in Zr–Nb alloy using positron annihilation spectroscopy and atom probe tomography

Atomic-scale analysis of liquid-gallium embrittlement of aluminum grain boundaries

Alloying Element Segregation and Grain Boundary Reconstruction, Atomistic Modeling

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