Chapter 93 Dislocations in Silicon at High Stress

Rabier, J.; Pizzagalli, Laurent; Demenet, J. L.

doi:10.1016/s1572-4859(09)01602-7

Cited by 59 publications

(59 citation statements)

References 100 publications

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“…3 presents the first study of silicon at low, but variable temperatures without a hydrostatic pressure component allowing analysis of the active slip systems and supporting the theoretical hypothesis of a change in slip system with temperature. [31,33] The conventional scheme for studies of directional plasticity in brittle crystals using microcompression on a polycrystalline sample in correlation with electron backscatter diffraction (EBSD) and where desired transmission electron microscopy (TEM) is shown in Fig. 4.…”

Section: Investigating Plasticity In Hard Crystalsmentioning

confidence: 99%

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Korte‐Kerzel

2017

MRS Communications

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Recent years have seen an increased application of small-scale uniaxial testing-microcompression-to the study of plasticity in macroscopically brittle materials. By suppressing fast fracture, new insights into deformation mechanisms of more complex crystals have become available, which had previously been out of reach of experiments. Structurally complex intermetallics, metallic compounds, or oxides are commonly brittle, but in some cases extraordinary, though currently mostly unpredictable, mechanical properties are found. This paper aims to give a survey of current advances, outstanding challenges, and practical considerations in testing such hard, brittle, and anisotropic crystals.While the origin of mechanical strength, toughness, and creep resistance is well studied in most metals, much less is known about the properties of more complex crystal structuresdespite their wide use as reinforcement phases and the undiscovered potential in their sheer number and variability. A major challenge in plasticity research of the next years will therefore be to close this gap in knowledge. Small-scale testing techniques have been demonstrated as a key enabling technique for such studies. Most prominent is microcompression, which helps overcome the fundamental challenge of studying plasticity in materials, which suffer from extreme brittleness in conventional testing. [1,2] Their plastic properties may, at first glance, appear to be of only academic interest: aiming to deduce fundamental relationships of crystal plasticity and structure to enable knowledge-guided search and data mining for new structural materials. However, they are in fact essential to performance at the microstructural scale of many advanced and highly alloyed materials and to understanding the effects of alloying strategies aimed at inducing deformability as baseline or reference information. Investigating plasticity in hard crystalsA deep understanding of plasticity and dislocation motion exists in most metallic crystals and strategies to engineer different aspects, for example by adjustment of the stacking fault energy, have been very successful. [3,4] These are being applied-with great effect-to hexagonal metals [3] which in spite of their closely related atomic packing show strongly anisotropic deformation and are therefore much more difficult to deform at low temperatures. In BCC metals, fundamental aspects of dislocation core structure, stress tensor dependence, and resulting non-Schmid behavior, are also still under investigation. [5,6] However, in all of these materials, the availability of large-grained or single crystals with sufficient purity has scarcely been a problem, nor has the ability to deform such samples under carefully controlled conditions. Suitable investigations by conventional, analytical and high-resolution microscopy techniques have also been carried out whenever new methods have allowed researchers to dive deeper into the physics of their plastic deformation.In intermetallics, ceramics, and compounds we face challeng...

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Section: Investigating Plasticity In Hard Crystalsmentioning

confidence: 99%

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Korte‐Kerzel

2017

MRS Communications

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“…In particular, this contribution of the core field leads to a dislocation-pressure interaction which can modify the kink formation energy and the dislocation line tension at high pressures 3 . Such a dependence of the dislocation energy with the pressure has been observed in atomistic simulations [25][26][27] . Eq.…”

Section: A Core Field Contributionmentioning

confidence: 57%

Dislocation core field. I. Modeling in anisotropic linear elasticity theory

Clouet

2011

Phys. Rev. B

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Aside from the Volterra field, dislocations create a core field, which can be modeled in linear anisotropic elasticity theory with force and dislocation dipoles. We derive an expression of the elastic energy of a dislocation taking full account of its core field and show that no cross term exists between the Volterra and the core fields. We also obtain the contribution of the core field to the dislocation interaction energy with an external stress, thus showing that dislocation can interact with a pressure. The additional force that derives from this core field contribution is proportional to the gradient of the applied stress. Such a supplementary force on dislocations may be important in high stress gradient regions, such as close to a crack tip or in a dislocation pile-up.

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“…198,199 These variables can affect fracture toughness by modifying dislocation character, nucleation, and mobility which shift the DBT temperature (DBTT) by hundreds of degrees. Recent studies from multiple disciplines, including geology, 200,201 physics, 202 civil engineering, 194 materials science, 147,203 and theoretical mechanics and applied mechanics, 192,193 have resulted in a consensus on what the key variables controlling the DBT are, but a comprehensive theory remains elusive.…”

Section: Future Nanomechanical Approaches To Brittleness Transitionsmentioning

confidence: 99%

Review Article: Case studies in future trends of computational and experimental nanomechanics

Tadmor

Kysar

Zimmerman

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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With rapidly increasing numbers of studies of new and exotic material uses for perovskites and quasicrystals, these demand newer instrumentation and simulation developments to resolve the revealed complexities. One such set of observational mechanics at the nanoscale is presented here for somewhat simpler material systems. The expectation is that these approaches will assist those materials scientists and physicists needing to verify atomistic potentials appropriate to the nanomechanical understanding of increasingly complex solids. The five following segments from nine University, National and Industrial Laboratories both review and forecast where some of the important approaches will allow a confirming of how in situ mechanics and nanometric visualization might unravel complex phenomena. These address two-dimensional structures, temporal models for the nanoscale, atomistic and multiscale friction fundamentals, nanoparticle surfaces and interfaces a) Electronic

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Chapter 93 Dislocations in Silicon at High Stress

Cited by 59 publications

References 100 publications

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Dislocation core field. I. Modeling in anisotropic linear elasticity theory

Review Article: Case studies in future trends of computational and experimental nanomechanics

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