中国物理B ›› 2024, Vol. 33 ›› Issue (8): 86105-086105.doi: 10.1088/1674-1056/ad4989

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Quasi-plastic deformation mechanisms and inverse Hall-Petch relationship in nanocrystalline boron carbide under compression

Zhen Yue(岳珍), Jun Li(李君)†, Lisheng Liu(刘立胜)‡, and Hai Mei(梅海)   

  1. Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan 430070, China
  • 收稿日期:2023-12-21 修回日期:2024-04-10 出版日期:2024-08-15 发布日期:2024-07-15
  • 通讯作者: Jun Li, Lisheng Liu E-mail:jun_li@whut.edu.cn;liulish@whut.edu.cn
  • 基金资助:
    The authors acknowledge the support from the National Natural Science Foundation of China (Grant No. 11972267).

Quasi-plastic deformation mechanisms and inverse Hall-Petch relationship in nanocrystalline boron carbide under compression

Zhen Yue(岳珍), Jun Li(李君)†, Lisheng Liu(刘立胜)‡, and Hai Mei(梅海)   

  1. Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan 430070, China
  • Received:2023-12-21 Revised:2024-04-10 Online:2024-08-15 Published:2024-07-15
  • Contact: Jun Li, Lisheng Liu E-mail:jun_li@whut.edu.cn;liulish@whut.edu.cn
  • Supported by:
    The authors acknowledge the support from the National Natural Science Foundation of China (Grant No. 11972267).

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摘要： Grain boundaries (GBs) play a significant role in the deformation behaviors of nanocrystalline ceramics. Here, we investigate the compression behaviors of nanocrystalline boron carbide (nB$_{4}$C) with varying grain sizes using molecular dynamics simulations with a machine-learning force field. The results reveal quasi-plastic deformation mechanisms in nB$_{4}$C: GB sliding, intergranular amorphization and intragranular amorphization. GB sliding arises from the presence of soft GBs, leading to intergranular amorphization. Intragranular amorphization arises from the interaction between grains with unfavorable orientations and the softened amorphous GBs, and finally causes structural failure. Furthermore, nB$_{4}$C models with varying grain sizes from 4.07 nm to 10.86 nm display an inverse Hall-Petch relationship due to the GB sliding mechanism. A higher strain rate in nB$_{4}$C often leads to a higher yield strength, following a $2/3$ power relationship. These deformation mechanisms are critical for the design of ceramics with superior mechanical properties.

关键词: nanocrystalline boron carbide, compression, grain boundary sliding, amorphization, inverse Hall-Petch behavior

Abstract: Grain boundaries (GBs) play a significant role in the deformation behaviors of nanocrystalline ceramics. Here, we investigate the compression behaviors of nanocrystalline boron carbide (nB$_{4}$C) with varying grain sizes using molecular dynamics simulations with a machine-learning force field. The results reveal quasi-plastic deformation mechanisms in nB$_{4}$C: GB sliding, intergranular amorphization and intragranular amorphization. GB sliding arises from the presence of soft GBs, leading to intergranular amorphization. Intragranular amorphization arises from the interaction between grains with unfavorable orientations and the softened amorphous GBs, and finally causes structural failure. Furthermore, nB$_{4}$C models with varying grain sizes from 4.07 nm to 10.86 nm display an inverse Hall-Petch relationship due to the GB sliding mechanism. A higher strain rate in nB$_{4}$C often leads to a higher yield strength, following a $2/3$ power relationship. These deformation mechanisms are critical for the design of ceramics with superior mechanical properties.

Key words: nanocrystalline boron carbide, compression, grain boundary sliding, amorphization, inverse Hall-Petch behavior

中图分类号:  (Grain and twin boundaries)

  • 61.72.Mm
62.20.F- (Deformation and plasticity) 02.70.Ns (Molecular dynamics and particle methods)