A model for grain boundary thermodynamics

Kamachali, Reza Darvishi

doi:10.1039/d0ra04682e

Cited by 40 publications

(19 citation statements)

References 73 publications

(112 reference statements)

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“…Using the density-based model, we can also develop GB phase diagrams for studying GB phase stability. This has been recently demonstrated for the binary Pt-Au 65 .…”

Section: Discussionmentioning

confidence: 69%

“…A thorough description of the density-based theory is given in ref. 65 . For a binary system, the mixing enthalpy and entropy terms have to be considered.…”

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

“…Using the continuum atomic density parameter here the coarse-grained coordination number can be seen as equivalent to the average interatomic distances among the atoms as well. The atomic density parameter enables a 'meanfield' approximation of the GB environment with reference to the adjacent bulk phase 65 . Compared to the classical phase-field models, since the atomic density field can be defined based on atomistic simulations, it can provide more quantitative physical interpretation of this field variable.…”

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

“…Assessment of the model parameters Since the current model and methodology can be applied for studying GB segregation and related phenomena in different materials, the associated model parameters are discussed. A further developed version of the density-based model is presented elsewhere 65 . For a flat GB in a pure substance, the equilibrium atomic density profile across the GB follows:…”

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

“…Detailed derivation of the density-based theory can be found in ref. 65 . Using atomistic simulations, the atomic density profile across the GB region is determined.…”

Section: Introductionmentioning

confidence: 99%

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Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries

et al. 2020

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Segregation to grain boundaries affects their cohesion, corrosion, and embrittlement and plays a critical role in heterogeneous nucleation. In order to quantitatively study segregation and low-dimensional phase separation at grain boundaries, here, we apply a density-based phase-field model. The current model describes the grain-boundary thermodynamic properties based on available bulk thermodynamic data, while the grain-boundary-density profile is obtained using atomistic simulations. To benchmark the performance of the model, Mn grain-boundary segregation in the Fe–Mn system is studied. 3D simulation results are compared against atom probe tomography measurements conducted for three alloy compositions. We show that a continuous increase in the alloy composition results in a discontinuous jump in the segregation isotherm. The jump corresponds to a spinodal phase separation at grain boundary. For alloy compositions above the jump, we reveal an interfacial transient spinodal phase separation. The transient spinodal phenomenon opens opportunities for knowledge-based microstructure design through the chemical manipulation of grain boundaries. The proposed density-based model provides a powerful tool to study thermodynamics and kinetics of segregation and phase changes at grain boundaries.

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“…Using the density-based model, we can also develop GB phase diagrams for studying GB phase stability. This has been recently demonstrated for the binary Pt-Au 65 .…”

Section: Discussionmentioning

confidence: 69%

“…A thorough description of the density-based theory is given in ref. 65 . For a binary system, the mixing enthalpy and entropy terms have to be considered.…”

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

Section: The Sum Of Kinetic (K Bmentioning

confidence: 99%

“…Detailed derivation of the density-based theory can be found in ref. 65 . Using atomistic simulations, the atomic density profile across the GB region is determined.…”

Section: Introductionmentioning

confidence: 99%

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Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries

et al. 2020

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Interstitial Segregation has the Potential to Mitigate Liquid Metal Embrittlement in Iron

Ahmadian

Scheiber

et al. 2023

Advanced Materials

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The embrittlement of metallic alloys by liquid metals leads to catastrophic material failure and severely impacts their structural integrity. The weakening of grain boundaries (GBs) by the ingress of liquid metal and preceding segregation in the solid are thought to promote early fracture. However, the potential of balancing between the segregation of cohesion‐enhancing interstitial solutes and embrittling elements inducing GB de‐cohesion is not understood. Here, the mechanisms of how boron segregation mitigates the detrimental effects of the prime embrittler, zinc, in a Σ5 [001] tilt GB in α‐Fe (4 at.% Al) is unveiled. Zinc forms nanoscale segregation patterns inducing structurally and compositionally complex GB states. Ab initio simulations reveal that boron hinders zinc segregation and compensates for the zinc‐induced loss in GB cohesion. The work sheds new light on how interstitial solutes intimately modify GBs, thereby opening pathways to use them as dopants for preventing disastrous material failure.

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Low Energy and Analog Memristor Enabled by Regulation of Ru ion Motion for High Precision Neuromorphic Computing

Kim

Kwon

Chun

et al. 2022

Adv Elect Materials

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Mobile species and matrix materials in ion motion‐mediated memristors predominantly determine the switching characteristics and device performance. As a result of exploring a new type of mobile species, a Ru ion‐mediated electrochemical metallization‐like memristor with an amorphous oxide matrix is recently suggested to achieve a low switching current, voltage, and good retention simultaneously. Although the ion migration of Ru in the oxide matrix is previously confirmed, no in‐depth study on how the crystallinity of the oxide matrix influences the Ru ion motion and switching characteristics has not been reported. Therefore, in this study, the crystallinity‐dependent resistive switching behavior of the Pt/HfO2/Ru structure device is investigated. With the crystallized HfO2 layer, the preferred Ru ion migration through the grain boundaries occurs owing to the enhanced ion mobility, resulting in a high switching current (≈100 µA) with continuous metallic Ru conducting filaments. The discontinuous conducting filaments with amorphous HfO2 exhibit a low switching current. In addition, highly linear and symmetric conductance modulation properties are achieved, and over 91.5% accuracy in the Mixed National Institute of Standards and Technology (MNIST) pattern recognition test is demonstrated.

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A model for grain boundary thermodynamics

Abstract: Density-based grain boundary thermodynamic assessment based on available bulk thermodynamic data teaches a pragmatic way to unlock microstructure defects engineering.

Cited by 40 publications

References 73 publications

Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries

Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries

Interstitial Segregation has the Potential to Mitigate Liquid Metal Embrittlement in Iron

Low Energy and Analog Memristor Enabled by Regulation of Ru ion Motion for High Precision Neuromorphic Computing

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