Dynamic and atomic-scale understanding of the twin thickness effect on dislocation nucleation and propagation activities by in situ bending of Ni nanowires

Wang, Lihua; Lü, Yan; Kong, Deli; Xiao, Lirong; Sha, Xuechao; Sun, Jia‐Lin; Zhang, Ze; Han, Xiao

doi:10.1016/j.actamat.2015.02.002

Cited by 35 publications

(33 citation statements)

References 51 publications

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“…It is well documented that the TBs are the effective obstruction to the dislocation motion, and the TBs are also stable against sliding or diffusion (both leading to softening) than the conventional GBs. These factors lead to the twin-structured metals exhibiting ultrahigh strength [4][5][6][7][8]. This strengthening mechanism, resulted from the TBs interaction with the dislocations, is clearly revealed by post-mortem transmission electron microscopy (TEM) investigations [5,9,10] and also confirmed by the molecular dynamic simulations [4,[11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 76%

“…Revealing the atomic-scale mechanism of how GBs accommodate large plasticity is crucial for understanding the performance of polycrystalline materials, since it can provide guidance to design the desired mechanical properties. Especially for the twin boundaries (TBs), the atomic-scale mechanism of how they accommodate large plasticity has been a global research focus for many years, which attribute to the fact that the twin-structured metals exhibit not only ultrahigh strength, but also considerable ductility [4,5].…”

Section: Introductionmentioning

confidence: 99%

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In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

Wang

Teng

et al. 2018

Ultramicroscopy

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Twin boundary can both strengthen and soften nanocrystalline metals and has been an important path for improving the strength and ductility of nano materials. Here, using in-lab developed double-tilt tensile stage in the transmission electron microscope, the atomic scale twin boundary shearing process was in situ observed in a twin-structured nanocrystalline Pt. It was revealed that the twin boundary shear was resulted from partial dislocation emissions on the intersected {111} planes, which accommodate as large as 47% shear strain. It is uncovered that the partial dislocations nucleated and glided on the two intersecting {111} slip planes lead to a transition of the original <110> symmetric tilt ∑3/(111) coherent twin boundary into a <110> symmetric tilt ∑9/(114) high angle grain boundary. These results provide insight of twin boundary strengthening mechanisms for accommodating plasticity strains in nanocrystalline metals.

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Section: Introductionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

Wang

Teng

et al. 2018

Ultramicroscopy

Self Cite

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“…TBs can act as barriers to impede dislocation motion. Some experimental work on the atomic level observations reveals the effect of grain size, 173,174 dislocation density, 175 twin thickness 176 on the interactions between dislocations and TBs, and the dislocation-TB reaction induced detwinning behaviors. 177,178 The development of in situ atomic scale experimental techniques promotes the investigation of dynamic dislocation-TB interaction modes.…”

Section: -151mentioning

confidence: 99%

“…177,178 The development of in situ atomic scale experimental techniques promotes the investigation of dynamic dislocation-TB interaction modes. 176,[179][180][181][182][183][184] Actually, the detailed interactions between dislocations and TBs are also widely investigated by means of MD simulations. Owing to the significant merit of MD simulation that the microstructure evolution can be tracked perfectly, the simulation studies on dislocation-TB interaction in NT metals have been comprehensively discussed in recent years.…”

Section: -151mentioning

confidence: 99%

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

Sun

2018

npj Comput Mater

117

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The recent studies on nanotwinned (NT) and hierarchical nanotwinned (HNT) face-centered cubic (FCC) metals are presented in this review. The HNT structures have been supposed as a kind of novel structure to bring about higher strength/ductility than NT counterparts in crystalline materials. We primarily focus on the recent developments of the experimental, atomistic and theoretical studies on the NT and HNT structures in the metallic materials. Some advanced bottom-up and top-down techniques for the fabrication of NT and HNT structures are introduced. The deformation induced HNT structures are available by virtue of severe plastic deformation (SPD) based techniques while the synthesis of growth HNT structures is so far almost unavailable. In addition, some representative molecular dynamics (MD) studies on the NT and HNT FCC metals unveil that the nanoscale effects such as twin spacing, grain size and plastic anisotropy greatly alter the performance of NT and HNT metals. The HNT structures may initiate unique phenomena in comparison with the NT ones. Furthermore, based on the phenomena and mechanisms revealed by experimental and MD simulation observations, a series of theoretical models have been proposed. They are effective to describe the mechanical behaviors of NT and HNT metals within the applicable scope. So far the development of manufacturing technologies of HNT structures, as well as the studies on the effects of HNT structures on the properties of metals are still in its infancy. Further exploration is required to promote the design of advanced materials.

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“…Such a transition of heterogeneous-to-homogeneous dislocation nucleation is responsible to the ductile-to-brittle transition in nanotwinned Au nanowires. The twin size effects on dislocation nucleation were also observed during bending of nanotwinned Ni nanowires 95 .…”

Section: Atomistic Deformation Mechanisms In Nanotwinned Metalsmentioning

confidence: 85%

Atomistic perspective on in situ nanomechanics

Wang

Mao

2016

Extreme Mechanics Letters

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Nanostructured materials exhibit superior physical and mechanical properties, and they hold great promise for enabling the development of novel micro/nano electromechanical systems. A fundamental understanding of the mechanical deformation and degradation in nanostructured materials is critical for designing the damage-tolerant nanostructures and devices. The in situ transmission electron microscopy provides a novel approach to uncover the dynamic deformation mechanisms in nanostructured materials, especially at the atomic scale. This review presents an overview of recent progress in the atomic-scale study of mechanical properties, dynamic deformation and degradation in a variety of nanostructured materials. Experimental techniques for in situ nanomechanical testing are reviewed. New insights into the atomic-level mechanical behavior of nanostructured materials are described, including surface-mediated defect processes, size-dependent deformation mechanisms, plastic deformation of nanotwinned and nanocrystalline materials, phase transformation, liquid-like behavior and pseudoelasticity, bending and fatigue, etc. Future research on the in situ nanomechanics is also discussed. Ultimately, the in situ nanomechanics study will enable a complete understanding of the atomic-scale dynamic deformation, thereby providing a mechanistic basis of the rational design and fabrication of durable nanomaterials and nanodevices.

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Dynamic and atomic-scale understanding of the twin thickness effect on dislocation nucleation and propagation activities by in situ bending of Ni nanowires

Cited by 35 publications

References 51 publications

In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

Nanotwinned and hierarchical nanotwinned metals: a review of experimental, computational and theoretical efforts

Atomistic perspective on in situ nanomechanics

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