Is hardness constant in covalent materials?

Sun, Guangpeng; Xing, Feng; Wu, Xue; Zhang, Sitong; Wen, Bin

doi:10.1016/j.jmst.2021.10.032

Cited by 14 publications

(8 citation statements)

References 46 publications

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“…Природа хрупкости элементарных полупроводников до сих пор не ясна [5][6][7][8][9][10]. Более того, неяснопочему при изгибе этих кристаллов в области T < T BDT трещина образуется без заметного пластичного течения?…”

Section: Introductionunclassified

“…Более того, неяснопочему при изгибе этих кристаллов в области T < T BDT трещина образуется без заметного пластичного течения? Существующие теории хрупкого разрушения основаны на результатах классической обратимой теории упругости с малыми деформациями [7][8][9][10]. При рассмотрении вопроса о распространении трещины в объеме вещества, в этих теориях, обычно не затрагивается проблема начального возникновения трещины.…”

Section: Introductionunclassified

“…Они сопровождают рост уже существующей трещины, экранируя ее, и влияют на скорость ее распространения. Но объяснить причину зарождения трещины на поверхности кристалла дислокационная модель так и не смогла, как и не смогла предложить метод расчета температуры хрупко-пластичного перехода в однокомпонентных ковалентных кристаллах [7][8][9][10]. Кроме того, дислокационная модель не может объяснить хрупкость стекла либо керамики, ибо дислокация (как краевая, так и винтовая) это линейный дефект кристаллической решётки.…”

Section: Introductionunclassified

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О Хрупкости Элементарных Полупроводников

Магомедов¹

2023

Физика Твердого Тела

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It is shown that the brittleness of a single-component covalent crystal (diamond, Si, Ge) is due to the “duplicity” of the paired potential of interatomic interaction for elastic (reversible) and for plastic (irreversible) deformation. This leads to the fact that the specific surface energy during plastic deformation of a covalent crystal is more than two times less than the specific surface energy during elastic deformation. Therefore, with a small deformation of a covalent crystal, it is energetically more advantageous to create a surface by irreversible breaking than by reversible elastic stretching. It is indicated that the brittle-ductile transition in a single-component covalent crystal is accompanied by metallization of covalent bonds on the surface. It is shown that the brittle-ductile transition temperature (TBDT) for single-component covalent crystals under static load has an upper limit: TBDT/Tm < 0.45, where Tm is the melting temperature.

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Section: Introductionunclassified

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О Хрупкости Элементарных Полупроводников

Магомедов¹

2023

Физика Твердого Тела

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“…To ensure the reliability and durability of engineering components, structural materials with very high performance are needed, and a very deep understanding of their strengthening mechanism is necessary. Since the strength is closely related to the microstructure, understanding and constructing the correlation between the strength and microstructure has always been an important research topic in materials science (Caillard, 2007;Wen et al, 2019;Xiao et al, 2020;Sun et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

A unified non-empirical strength model

Xing

Sun²,

Zhang³

et al. 2023

Front. Mater.

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Strength, as an important indicator of structural materials, has always been an important research topic in materials science. Theoretically, building a strength model is a rewarding method to understand the relationship between the mechanical properties and microstructure of materials. Although many strength models can reduplicate experimental values very well, they are empirical models, and their applicability is limited to materials for which empirical parameters have been obtained. Here, a non-empirical strength model is proposed based on the two-dimensional (2D) displacement potential of dislocation slipping, which can be applied to different chemically bonded crystals. Owing to the large electron localization function (ELF), covalent and ionic crystals have a high 2D displacement potential of dislocation slipping, and their dislocation slip mode prefers the kink-pair mode, further exhibiting a high critical resolved shear stress (CRSS). In contrast, metallic crystals with a small ELF have a low 2D displacement potential of dislocation slipping, and their dislocation slip mode is more inclined to the string mode, showing a low CRSS. This work provides new insights into dislocation-slipping configurations that will be useful for the development of new high-performance structural materials.

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Section: Introductionmentioning

confidence: 99%

A unified nonempirical strength model

Feng

Sun

Zhang

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Strength, as an important indicator of structural materials, has always been an important research topic in materials science. Theoretically, building a strength model is a rewarding method to understand the relationship between the mechanical properties and microstructure of materials. Although many strength models can reduplicate experimental values very well, they are empirical models, and their applicability is limited to materials for which empirical parameters have been obtained. Here, a nonempirical strength model is proposed based on the two-dimensional (2D) displacement potential of dislocation slipping, which can be applied to different chemically bonded crystals. Owing to the large electron localization function (ELF), covalent and ionic crystals have a high 2D displacement potential of dislocation slipping, and their dislocation slip mode prefers the kink-pair mode, further exhibiting a high critical resolved shear stress (CRSS). In contrast, metallic crystals with a small ELF have a low 2D displacement potential of dislocation slipping, and their dislocation slip mode is more inclined to the string mode, showing a low CRSS. This work provides new insights into dislocation-slipping configurations that will be useful for the development of new high-performance structural materials.

show abstract

Is hardness constant in covalent materials?

Cited by 14 publications

References 46 publications

О Хрупкости Элементарных Полупроводников

О Хрупкости Элементарных Полупроводников

A unified non-empirical strength model

A unified nonempirical strength model

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