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

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

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Grain boundaries(GBs)play a significant role in the deformation behaviors of nanocrystalline ceramics.Here,we investigate the compression behaviors of nanocrystalline boron carbide(nB4C)with varying grain sizes using molecular dynamics simulations with a machine-learning force field.The results reveal quasi-plastic deformation mechanisms in nB4C: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,nB4C 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 nB4C 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.

nanocrystalline boron carbidecompressiongrain boundary slidingamorphizationinverse Hall-Petch behavior

岳珍、李君、刘立胜、梅海

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Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics,Wuhan University of Technology,Wuhan 430070,China

National Natural Science Foundation of China

11972267

2024

中国物理B(英文版)
中国物理学会和中国科学院物理研究所

中国物理B(英文版)

CSTPCDEI
影响因子:0.995
ISSN:1674-1056
年,卷(期):2024.33(8)