Reaching near-theoretical strength by achieving quasi-homogenous surface dislocation nucleation in MgO particles

Chen, Sijing; Liu, Fei; Liu, Boyu; Chen, Xiao; Ke, Xiaoxing; Zhang, Manchen; Tang, X.C.; Guan, Pengfei; Zhang, Ze; Shan, Zhiwei; Qian, Yu

doi:10.1016/j.mattod.2022.04.007

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…A similar behavior has been reported in the compression of defect-free Mo alloy single-crystal micropillars . This common phenomenon observed in micro/nanosized crystals is usually associated with dislocation nucleation and movement in perfect microparticles/cubes. − ,− Furthermore, it has been found that in the elastic stage, the load–displacement curve of the microparticles follows either a linear or a power-law response, which originates from the difference in the local contact between the flat indenter and the microparticles determined by FEA simulations and theoretical analysis (supplementary section S3).…”

Section: Resultssupporting

confidence: 70%

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Lu,

Pan,

Fang

et al. 2024

J. Phys. Chem. C

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Single crystal Cu microparticles with varied sizes and good crystallinity were batch-fabricated by a flash arc synthesis (FAS) method. The size and extreme plastic deformation-dependent mechanical behaviors of Cu microparticles were investigated through in situ mechanical tests under scanning electron microscopy (SEM). It is noted that the Cu microparticles exhibit near theoretical strength at much larger sizes by comparison with reported values, accompanied by the weak size effect on strength, which we attribute to the high quality of the prepared Cu microparticles. Besides, the hardness of precompressed Cu microparticles increases sharply with the increase of the residual strain, which we attribute to the obstruction of dislocation movement by the drastically increased contact interfaces during extreme plastic deformation and the high hydrostatic pressure induced by friction at the contact interfaces. Then, an extended Taylor hardening model is developed to quantify the residual strain-dependent hardness.

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Section: Resultssupporting

confidence: 70%

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Lu,

Pan,

Fang

et al. 2024

J. Phys. Chem. C

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“…Currently, various strategies are set up to further enhance the mechanical properties of alumina compounds including powder size refinement at the nanoscale with the aim to target alumina‐based ceramics with submicron grain size after compaction and sintering 7 . Indeed and as for metals, reducing the size of single‐crystalline ceramics deep in the submicron scale is known to promote the brittle‐to‐ductile transition and postpone (or inhibit) the brittle fracture process currently observed in ceramics single crystals 8–13 . Nevertheless, some questions remain about the plastic deformation mechanisms at the origin of such behavior.…”

Section: Introductionmentioning

confidence: 99%

“…7 Indeed and as for metals, reducing the size of single-crystalline ceramics deep in the submicron scale is known to promote the brittle-to-ductile transition and postpone (or inhibit) the brittle fracture process currently observed in ceramics single crystals. [8][9][10][11][12][13] Nevertheless, some questions remain about the plastic deformation mechanisms at the origin of such behavior. Especially in the case of 𝛼-alumina where a bet-ter understanding of the stress response and elementary deformation processes might significantly help to better assess the fabrication of fine-grain samples.…”

Section: Introductionmentioning

confidence: 99%

Atomistic simulation of α‐Al₂O₃ nanoparticle plastic anisotropy under compression

Chevalier

Amodeo

2023

J Am Ceram Soc.

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Alumina (𝛼-Al 2 O 3 ) is one of the major ceramic oxides commonly used for its advanced mechanical properties. Since recently, nanoscale 𝛼-Al 2 O 3 requires more in-depth characterization related to ceramic powder compaction and sintering as well as for applications in the field of biomedical engineering. In this study, we use classical molecular dynamics simulations with a 2/3-body interatomic potential to investigate the mechanical response and the elementary deformation processes of 𝛼-Al 2 O 3 nanoparticles under compression. Resultsshow that 𝛼-Al 2 O 3 nanoparticles resist up to particularly elevated critical force before yielding due to a surface nucleation process including various kinds of dislocations and nanotwins strongly sensitive to orientation and temperature. Results are rationalized in terms of stacking-fault energy and shear stress analysis and are discussed in the light of recent micromechanical tests as well as more fundamental observations performed in the bulk material.

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Uniting Ultrahigh Plasticity with Near‐Theoretical Strength in Submicron‐Scale Si via Surface Healing

Xu,

Yu,

Ding

et al. 2024

Adv Funct Materials

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As a typical hard but brittle material, Si tends to fracture abruptly at a stress well below its theoretical strength, even if the tested volume goes down to submicron scale, at which materials are usually nearly free of flaws or extended defects. Here, via the thermal–oxidation–mediated healing of the surface that is the preferred site for cracks or dislocations initiation, the premature fracture can be effectively inhibited and the over 50% homogeneous plastic strain with the near‐theoretical strength (twice the value of the unhealed counterpart) are united in submicron‐sized Si particles. In situ transmission electron microscope observations and atomistic simulations elucidate the confinement effect from the passivated and smoothened thermal oxide, which retards the dislocation nucleation and transforms the dominant deformation mechanism from partial dislocation to the more mobile full dislocation. This work demonstrates an effective and feasible surface engineering pathway to optimize the mechanical properties of Si at small scales.

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Reaching near-theoretical strength by achieving quasi-homogenous surface dislocation nucleation in MgO particles

Cited by 8 publications

References 25 publications

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Atomistic simulation of α‐Al₂O₃ nanoparticle plastic anisotropy under compression

Uniting Ultrahigh Plasticity with Near‐Theoretical Strength in Submicron‐Scale Si via Surface Healing

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Reaching near-theoretical strength by achieving quasi-homogenous surface dislocation nucleation in MgO particles

Cited by 8 publications

References 25 publications

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Weak Size-Dependent Strength and Extreme Plastic Deformation of Single Crystal Cu Microparticles

Atomistic simulation of α‐Al2O3 nanoparticle plastic anisotropy under compression

Uniting Ultrahigh Plasticity with Near‐Theoretical Strength in Submicron‐Scale Si via Surface Healing

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Product

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Atomistic simulation of α‐Al₂O₃ nanoparticle plastic anisotropy under compression