Small-Angle Twist Grain Boundaries as Sinks for Point Defects

Jiang, Hao; Szlufarska, Izabela

doi:10.1038/s41598-018-21433-7

Cited by 19 publications

(7 citation statements)

References 46 publications

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“…For this low-twist angle GB, the boundary is comprised of a grid of 1/6 112 partial screw dislocations with alternating regions of FCC (atoms colored in black) and HCP (atoms colored in gray) structures. Similar interfacial dislocation networks in low-twist angle GBs have been recently observed in atomistic calculations 66 . Chen et al 67 examined the GB character distribution in the Cantor alloy during recrystallization and showed a high density of twin 3 and low-angle GBs.…”

Section: Resultssupporting

confidence: 82%

Tensile deformation behavior of twist grain boundaries in CoCrFeMnNi high entropy alloy bicrystals

Lee

Shabani

Pataky

et al. 2021

Sci Rep

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High entropy alloys (HEA) are a class of materials that consist of multiple elemental species in similar concentrations. The use of elements in far from dilute concentrations introduces a multi-dimensional composition design space by which the properties of metallic systems can be tailored. While the mechanical behavior of HEAs has been the subject of active research recently, the role of grain boundaries (GBs) in their deformation behavior remains poorly understood. Motivated by recent experiments on HEAs demonstrating that GBs act as nucleation sites for deformation twins, herein, we leverage atomistic simulations to construct a series of equiatomic CoCrFeMnNi HEA bicrystals with $$\langle 110 \rangle$$ ⟨ 110 ⟩ and $$\langle 111 \rangle$$ ⟨ 111 ⟩ symmetric twist GBs and examine their tensile behavior and underlying deformation mechanisms at 77 K. Simulation results reveal that plastic deformation proceeds by the nucleation of partial dislocations from GBs, which then grow with further loading by bowing into the bulk crystals leaving behind stacking faults. Variations in the nucleation stress exist as function of GB character, defined in this work by the twist angle. Our results provide future avenues to explore GBs as a microstructure design tool to develop HEAs with tailored properties.

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Section: Resultssupporting

confidence: 82%

Tensile deformation behavior of twist grain boundaries in CoCrFeMnNi high entropy alloy bicrystals

Lee

Shabani

Pataky

et al. 2021

Sci Rep

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“…On this direction, the Mg 32 (Zn,Al) 49 T‐phase showed promising results, although the mechanisms behind its high radiation resistance remains as yet unknown. –The displacement damage yield must be reduced, i.e., the nucleation and growth of extended radiation‐induced defects (e.g., dislocation loops) must be suppressed in these new alloys as they can increase the hardness by facilitating the radiation‐induced precipitation, possibly resulting in severe embrittlement. Following a recent trend observed in the literature, [ 98–102 ] new alloys with reduced grain sizes should be designed as the increase in the density of sinks (grain‐boundaries) will result in less accumulation of radiation‐induced point defects within the grains.…”

Section: Discussionmentioning

confidence: 99%

Prototypic Lightweight Alloy Design for Stellar‐Radiation Environments

et al. 2020

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The existing literature data shows that conventional aluminium alloys may not be suitable for use in stellar-radiation environments as their hardening phases are prone to dissolve upon exposure to energetic irradiation, resulting in alloy softening which may reduce the lifetime of such materials impairing future human-based space missions. The innovative methodology of crossover alloying is herein used to synthesize an aluminium alloy with a radiation resistant hardening phase. This alloy-a crossover of 5xxx and 7xxx series Al-alloys-is subjected to extreme heavy ion irradiations in situ within a TEM up to a dose of 1 dpa and major experimental observations are made: the Mg 32 (Zn,Al) 49 hardening precipitates (denoted as T-phase) for this alloy system surprisingly survive the extreme irradiation conditions, no cavities are found to nucleate and displacement damage is observed to develop in the form of black-spots. This discovery indicates that a high phase fraction of hardening precipitates is a crucial parameter for achieving superior radiation tolerance. Based on such observations, this current work sets new guidelines for the design of metallic alloys for space exploration.

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“…Polycrystalline thin films are the core materials for several opto-electronic applications due to their fast fabrication and low manufacturing cost. − Polycrystalline materials like Cu(In,Ga)Se 2 , (CIGS), CdTe, or the recent perovskite materials − constitute as the photovoltaic absorbers of the growing class of thin-film solar cells, with efficiencies of more than 25% already attained with perovskite solar cells, close to those of wafer-based single-crystalline silicon. , The grain boundary (GB) properties of polycrystalline materials and the physics behind that have received great interest in the research community. GBs are the source for dangling bonds, vacancies, and voids, as well as other defects. − Different grain sizes in polycrystalline materials result in high internal interfacial areas, and the boundaries in between them play a complex role in determining the optoelectronic properties of the semiconductor materials and have a great impact in the efficiency of the resulting devices. − Depending on the material properties, GBs have positive and/or negative impacts on the performance of the polycrystalline material-based devices. For single-crystal silicon, the defects within the grains, such as stacking faults and dislocations for impurities, chiefly lead to recombination losses in these areas. , Typically, methylammonium lead iodide (MAPbI 3 ) perovskite thin films are polycrystalline with grain sizes ranging from 100 nm to a few microns, , and GBs are the regions with a high density of non-radiative recombination centers, which can diminish photoluminescence (PL), lifetime, and other effects. , There are a number of publications on MAPbI 3 perovskite thin films; however, the effect of the GBs on the electrical characteristics of the film and the performance of the solar cells is still the subject of intense discussion.…”

Section: Introductionmentioning

confidence: 99%

Observation of Grain Boundary Passivation and Charge Distribution in Perovskite Films Improved with Anti-solvent Treatment

Panigrahi¹,

Calmeiro²,

Mendes³

et al. 2022

J. Phys. Chem. C

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Owing to the polycrystalline nature of hybrid perovskite thin films, the trap states in grain boundaries (GBs) introduced by charged defects play an important role in determining the charge collection efficiency and have a significant impact on their optoelectronic properties. Herein, we show the direct imaging of the GB passivation of perovskite films through an anti-solvent treatment and the anomalous charge distribution across the films due to the passivation. The downward band bending at the GBs has been observed at nanometer scale using Kelvin probe force microscopy. This revealed that a hot chlorobenzene treatment decreases the band bending at GBs and allows more homogeneous electronic properties throughout the film after passivation. Conductive atomic force microscopy has been employed to show the charge transport mapping across the films. It was found that the passivation effect not only changes the surface potential at GBs but also enhances the overall charge collection efficiency of the film. Our work provides a solution to reduce the density of charge defects at GBs through hot anti-solvent treatment, which is demonstrated to be a promising strategy to decrease the recombination losses at GBs and, thereby, increase the electronic quality of the perovskite films as well as enhance the device performance.

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Small-Angle Twist Grain Boundaries as Sinks for Point Defects

Cited by 19 publications

References 46 publications

Tensile deformation behavior of twist grain boundaries in CoCrFeMnNi high entropy alloy bicrystals

Tensile deformation behavior of twist grain boundaries in CoCrFeMnNi high entropy alloy bicrystals

Prototypic Lightweight Alloy Design for Stellar‐Radiation Environments

Observation of Grain Boundary Passivation and Charge Distribution in Perovskite Films Improved with Anti-solvent Treatment

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