Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties

Shihua Ma; Weihong Liu; Qian Li; Jun Zhang; Shasha Huang; Yaoxu Xiong; Biao Xu; Tao Yang; Shijun Zhao

doi:10.1016/j.actamat.2023.119537

Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties

Shihua Ma, Weihong Liu, Qian Li, Jun Zhang, Shasha Huang, Yaoxu Xiong, Biao Xu, Tao Yang, Shijun Zhao^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

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Abstract

Elemental segregation around extended defects is common in high-entropy alloys (HEAs) composed of multi-principal elements, which profoundly impacts their mechanical properties. In HEAs, the driving force for segregation usually competes with chemical short-range ordering (CSRO) formation, making it challenging to elucidate the segregation mechanisms. In this study, we systematically investigate the chemical composition changes around extended defects, including dislocations, stacking faults, and grain boundaries (GBs) in CoNiCrFe HEAs, to explore the chemical-structure-mechanical relationship utilizing hybrid Monte Carlo and molecular dynamic (MC/MD) simulations and theoretical analysis. We find a pronounced Cr enrichment and Co/Ni/Fe depletion around all defects considered in this work. A correlation between the degree of structural disorder and the chemical segregation/depletion phenomenon in the proximity of extended defects has been uncovered. Our results show that due to the extreme chemical complexity in HEAs, CSRO inevitably contributes to the elemental rearrangement and affects segregation. Consequently, the segregation behavior in HEAs is mainly controlled by interactions between different atomic pairs, and the segregation entropy also plays a dominant role. By decoupling the strengthening contribution from elemental segregation and CSRO, we demonstrate and highlight that the strengthening in HEAs can be modulated by elemental segregation. The positive impact of element segregation on interfacial properties - improved ultimate tensile strength and elongation, has been evidenced through experimental comparisons of CoNiCrFe with different Fe additions. This work elucidates the mechanism of heterogenous elemental distributions in HEAs where elemental segregation and CSRO coexist, paving the way for manipulating their mechanical properties by modulating the compositional variations.

© 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Original language	English
Article number	119537
Journal	Acta Materialia
Volume	264
Online published	15 Nov 2023
DOIs	https://doi.org/10.1016/j.actamat.2023.119537
Publication status	Published - 1 Jan 2024

Funding

This work was supported by the National Natural Science Foundation of China (No. 11975193), and Research Grant Council of Hong Kong (No. 11200421).

Research Keywords

High-entropy alloys
Grain boundary
Segregation
Chemical short-range ordering
Decohesion resistance

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COPYRIGHT TERMS OF DEPOSITED POSTPRINT FILE: © 2023 Acta Materialia Inc. Published by Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/.

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RGC-funded

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title = "Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties",

abstract = "Elemental segregation around extended defects is common in high-entropy alloys (HEAs) composed of multi-principal elements, which profoundly impacts their mechanical properties. In HEAs, the driving force for segregation usually competes with chemical short-range ordering (CSRO) formation, making it challenging to elucidate the segregation mechanisms. In this study, we systematically investigate the chemical composition changes around extended defects, including dislocations, stacking faults, and grain boundaries (GBs) in CoNiCrFe HEAs, to explore the chemical-structure-mechanical relationship utilizing hybrid Monte Carlo and molecular dynamic (MC/MD) simulations and theoretical analysis. We find a pronounced Cr enrichment and Co/Ni/Fe depletion around all defects considered in this work. A correlation between the degree of structural disorder and the chemical segregation/depletion phenomenon in the proximity of extended defects has been uncovered. Our results show that due to the extreme chemical complexity in HEAs, CSRO inevitably contributes to the elemental rearrangement and affects segregation. Consequently, the segregation behavior in HEAs is mainly controlled by interactions between different atomic pairs, and the segregation entropy also plays a dominant role. By decoupling the strengthening contribution from elemental segregation and CSRO, we demonstrate and highlight that the strengthening in HEAs can be modulated by elemental segregation. The positive impact of element segregation on interfacial properties - improved ultimate tensile strength and elongation, has been evidenced through experimental comparisons of CoNiCrFe with different Fe additions. This work elucidates the mechanism of heterogenous elemental distributions in HEAs where elemental segregation and CSRO coexist, paving the way for manipulating their mechanical properties by modulating the compositional variations.{\textcopyright} 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.",

keywords = "High-entropy alloys, Grain boundary, Segregation, Chemical short-range ordering, Decohesion resistance",

author = "Shihua Ma and Weihong Liu and Qian Li and Jun Zhang and Shasha Huang and Yaoxu Xiong and Biao Xu and Tao Yang and Shijun Zhao",

year = "2024",

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doi = "10.1016/j.actamat.2023.119537",

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T1 - Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties

AU - Ma, Shihua

AU - Liu, Weihong

AU - Li, Qian

AU - Zhang, Jun

AU - Huang, Shasha

AU - Xiong, Yaoxu

AU - Xu, Biao

AU - Yang, Tao

AU - Zhao, Shijun

PY - 2024/1/1

Y1 - 2024/1/1

N2 - Elemental segregation around extended defects is common in high-entropy alloys (HEAs) composed of multi-principal elements, which profoundly impacts their mechanical properties. In HEAs, the driving force for segregation usually competes with chemical short-range ordering (CSRO) formation, making it challenging to elucidate the segregation mechanisms. In this study, we systematically investigate the chemical composition changes around extended defects, including dislocations, stacking faults, and grain boundaries (GBs) in CoNiCrFe HEAs, to explore the chemical-structure-mechanical relationship utilizing hybrid Monte Carlo and molecular dynamic (MC/MD) simulations and theoretical analysis. We find a pronounced Cr enrichment and Co/Ni/Fe depletion around all defects considered in this work. A correlation between the degree of structural disorder and the chemical segregation/depletion phenomenon in the proximity of extended defects has been uncovered. Our results show that due to the extreme chemical complexity in HEAs, CSRO inevitably contributes to the elemental rearrangement and affects segregation. Consequently, the segregation behavior in HEAs is mainly controlled by interactions between different atomic pairs, and the segregation entropy also plays a dominant role. By decoupling the strengthening contribution from elemental segregation and CSRO, we demonstrate and highlight that the strengthening in HEAs can be modulated by elemental segregation. The positive impact of element segregation on interfacial properties - improved ultimate tensile strength and elongation, has been evidenced through experimental comparisons of CoNiCrFe with different Fe additions. This work elucidates the mechanism of heterogenous elemental distributions in HEAs where elemental segregation and CSRO coexist, paving the way for manipulating their mechanical properties by modulating the compositional variations.© 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

AB - Elemental segregation around extended defects is common in high-entropy alloys (HEAs) composed of multi-principal elements, which profoundly impacts their mechanical properties. In HEAs, the driving force for segregation usually competes with chemical short-range ordering (CSRO) formation, making it challenging to elucidate the segregation mechanisms. In this study, we systematically investigate the chemical composition changes around extended defects, including dislocations, stacking faults, and grain boundaries (GBs) in CoNiCrFe HEAs, to explore the chemical-structure-mechanical relationship utilizing hybrid Monte Carlo and molecular dynamic (MC/MD) simulations and theoretical analysis. We find a pronounced Cr enrichment and Co/Ni/Fe depletion around all defects considered in this work. A correlation between the degree of structural disorder and the chemical segregation/depletion phenomenon in the proximity of extended defects has been uncovered. Our results show that due to the extreme chemical complexity in HEAs, CSRO inevitably contributes to the elemental rearrangement and affects segregation. Consequently, the segregation behavior in HEAs is mainly controlled by interactions between different atomic pairs, and the segregation entropy also plays a dominant role. By decoupling the strengthening contribution from elemental segregation and CSRO, we demonstrate and highlight that the strengthening in HEAs can be modulated by elemental segregation. The positive impact of element segregation on interfacial properties - improved ultimate tensile strength and elongation, has been evidenced through experimental comparisons of CoNiCrFe with different Fe additions. This work elucidates the mechanism of heterogenous elemental distributions in HEAs where elemental segregation and CSRO coexist, paving the way for manipulating their mechanical properties by modulating the compositional variations.© 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

KW - High-entropy alloys

KW - Grain boundary

KW - Segregation

KW - Chemical short-range ordering

KW - Decohesion resistance

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U2 - 10.1016/j.actamat.2023.119537

DO - 10.1016/j.actamat.2023.119537

M3 - RGC 21 - Publication in refereed journal

SN - 1359-6454

VL - 264

JO - Acta Materialia

JF - Acta Materialia

M1 - 119537

ER -

Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties

Abstract

Funding

Research Keywords

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RGC Funding Information

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CRF: Designing Self-healing High Entropy Alloys for Advanced Nuclear Applications

GRF: Irradiation Damage Mechanism of Multicomponent Transition Metal Carbides

Cite this

Mechanism of elemental segregation around extended defects in high-entropy alloys and its effect on mechanical properties

Abstract

Funding

Research Keywords

Publisher's Copyright Statement

RGC Funding Information

Access Output

Other Access Options

Permanent Link

Other Files and Links

Fingerprint

Projects

CRF: Designing Self-healing High Entropy Alloys for Advanced Nuclear Applications

GRF: Irradiation Damage Mechanism of Multicomponent Transition Metal Carbides

Cite this