Inhibiting the inverse Hall-Petch behavior in CoCuFeNiPd high-entropy alloys with short-range ordering and grain boundary segregation

IF 5.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Scripta Materialia Pub Date : 2022-12-01 DOI:10.1016/j.scriptamat.2022.114950

Weiming Ji, Mao See Wu

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Abstract

The mechanical implications of short-range ordering (SRO) and grain boundary (GB) segregation in the inverse Hall-Petch behavior of nanocrystalline CoCuFeNiPd high-entropy alloys (HEAs) were studied using hybrid Monte Carlo (MC)/Molecular Dynamics (MD) simulations. Results show that the presences of SRO and GB segregation inhibit the grain size softening (inverse Hall-Petch relation), leading to grain-size independence of the high flow stress. We find that the dislocation nucleation at triple junctions is suppressed by the SRO due to the increased stacking fault energy, which attenuates the dislocation activities. Furthermore, the strain localization at GBs is intensified by the GB segregation due to the increased GB energy, which facilitates the GB activities and glass-like deformation. The GB-governed plasticity associated with glass-like deformation leads to suppression of the inverse Hall-Petch effect. These findings may provide useful strategies for the design of high-performance HEAs by tuning the GB composition and SRO structure.

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用近程有序和晶界偏析抑制CoCuFeNiPd高熵合金的逆Hall-Petch行为

采用蒙特卡罗(MC)/分子动力学(MD)混合模拟方法研究了纳米晶CoCuFeNiPd高熵合金(HEAs)的近程有序(SRO)和晶界偏析(GB)在逆Hall-Petch行为中的力学意义。结果表明，SRO和GB偏析的存在抑制了晶粒尺寸的软化(相反的Hall-Petch关系)，导致晶粒尺寸不受高流变应力的影响。我们发现，由于层错能的增加，位错活动减弱，位错在三结处的成核受到SRO的抑制。此外，由于GB能量的增加，GB偏析加剧了在GB处的应变局部化，这有利于GB的活性和玻璃样变形。与玻璃样变形相关的gb控制塑性导致了反向霍尔-佩奇效应的抑制。这些发现可能为通过调整GB组成和SRO结构来设计高性能HEAs提供有用的策略。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Scripta Materialia 工程技术-材料科学：综合

CiteScore

11.40

自引率

5.00%

发文量

581

审稿时长

34 days

期刊介绍： Scripta Materialia is a LETTERS journal of Acta Materialia, providing a forum for the rapid publication of short communications on the relationship between the structure and the properties of inorganic materials. The emphasis is on originality rather than incremental research. Short reports on the development of materials with novel or substantially improved properties are also welcomed. Emphasis is on either the functional or mechanical behavior of metals, ceramics and semiconductors at all length scales.