The Experts below are selected from a list of 19077 Experts worldwide ranked by ideXlab platform

Daniel Nelias - One of the best experts on this subject based on the ideXlab platform.

  • self emitted surface corrugations in dynamic fracture of Silicon Single Crystal
    Proceedings of the National Academy of Sciences of the United States of America, 2020
    Co-Authors: Meng Wang, Lv Zhao, Marion Fourmeau, Franck Legrand, Daniel Nelias
    Abstract:

    When a dynamic crack front travels through material heterogeneities, elastic waves are emitted, which perturb the crack and change the morphology of the fracture surface. For asperity-free Crystalline materials, crack propagation along preferential cleavage planes is expected to present a smooth crack front and form a mirror-like fracture surface. Surprisingly, we show here that in Single Crystalline Silicon without material asperities, the crack front presents a local kink during high-speed crack propagation. Meanwhile, local oscillations of the crack front, which can move along the crack front, emerge at the front kink position and generate periodic fracture surface corrugations. They grow from angstrom amplitude to a few hundred nanometers and propagate with a long lifetime at a frequency-dependent speed, while keeping a scale-independent shape. In particular, the local front oscillations collide in a particle-like manner rather than proceeding with a linear superposition upon interaction, which presents the characteristic of solitary waves. We propose that such a propagating mode of the crack front, which results from the fracture energy fluctuation at a critical crack speed in the Silicon Crystal, can be considered as nonlinear elastic waves that we call "corrugation waves."

  • velocity correlated crack front and surface marks in Single Crystalline Silicon
    Nature Communications, 2018
    Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel Nelias
    Abstract:

    Single Crystalline Silicon fractures on low-energy cleavage planes such as (111) and (110). The crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in Silicon Single Crystal rapidly accelerates to 3700 m/s without crack path deviation or crack branching, contrasting previous observations. We highlight that the crack front shape involves strong velocity dependence and presents a curvature jump during very high-speed crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the crack front in the absence of material asperity.

T B Britton - One of the best experts on this subject based on the ideXlab platform.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    Ultramicroscopy, 2019
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Abstract Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. Using this technique, we can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed α-iron sample. The speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    arXiv: Materials Science, 2018
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. This technique can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The orientation is further refined with rapid measurement of misorientation using whole pattern matching. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed {\alpha}-iron sample. The drastic speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.

Lv Zhao - One of the best experts on this subject based on the ideXlab platform.

  • self emitted surface corrugations in dynamic fracture of Silicon Single Crystal
    Proceedings of the National Academy of Sciences of the United States of America, 2020
    Co-Authors: Meng Wang, Lv Zhao, Marion Fourmeau, Franck Legrand, Daniel Nelias
    Abstract:

    When a dynamic crack front travels through material heterogeneities, elastic waves are emitted, which perturb the crack and change the morphology of the fracture surface. For asperity-free Crystalline materials, crack propagation along preferential cleavage planes is expected to present a smooth crack front and form a mirror-like fracture surface. Surprisingly, we show here that in Single Crystalline Silicon without material asperities, the crack front presents a local kink during high-speed crack propagation. Meanwhile, local oscillations of the crack front, which can move along the crack front, emerge at the front kink position and generate periodic fracture surface corrugations. They grow from angstrom amplitude to a few hundred nanometers and propagate with a long lifetime at a frequency-dependent speed, while keeping a scale-independent shape. In particular, the local front oscillations collide in a particle-like manner rather than proceeding with a linear superposition upon interaction, which presents the characteristic of solitary waves. We propose that such a propagating mode of the crack front, which results from the fracture energy fluctuation at a critical crack speed in the Silicon Crystal, can be considered as nonlinear elastic waves that we call "corrugation waves."

  • velocity correlated crack front and surface marks in Single Crystalline Silicon
    Nature Communications, 2018
    Co-Authors: Lv Zhao, Didier Bardel, Anne Maynadier, Daniel Nelias
    Abstract:

    Single Crystalline Silicon fractures on low-energy cleavage planes such as (111) and (110). The crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in Silicon Single Crystal rapidly accelerates to 3700 m/s without crack path deviation or crack branching, contrasting previous observations. We highlight that the crack front shape involves strong velocity dependence and presents a curvature jump during very high-speed crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the crack front in the absence of material asperity.

  • Velocity correlated crack front and surface marks in Single Crystalline Silicon
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Lv Zhao, Bardel Didier, Maynadier Anne, Nelias Daniel
    Abstract:

    International audienceSingle Crystalline Silicon fractures on low-energy cleavage planes such as (111) and (110). The crack propagation cannot accurately be predicted by linear elastic fracture mechanics since it does not account for small scale and inelastic phenomena such as atomic lattice trapping. Here we show that, under pure bending load, (110) cleavage in Silicon Single Crystal rapidly accelerates to 3700 m/s without crack path deviation or crack branching, contrasting previous observations. We highlight that the crack front shape involves strong velocity dependence and presents a curvature jump during very high-speed crack growth. In addition, we observe special marks—a kind of periodic surface undulation—that exclusively arise on the rapid fracture surfaces, and we suggest that they are front wave traces resulting from an intrinsic local velocity fluctuation. This finding gives insight to the wavy nature of the crack front in the absence of material asperity

David M Collins - One of the best experts on this subject based on the ideXlab platform.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    Ultramicroscopy, 2019
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Abstract Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. Using this technique, we can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed α-iron sample. The speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    arXiv: Materials Science, 2018
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. This technique can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The orientation is further refined with rapid measurement of misorientation using whole pattern matching. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed {\alpha}-iron sample. The drastic speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.

Alexander Foden - One of the best experts on this subject based on the ideXlab platform.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    Ultramicroscopy, 2019
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Abstract Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. Using this technique, we can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed α-iron sample. The speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.

  • indexing electron backscatter diffraction patterns with a refined template matching approach
    arXiv: Materials Science, 2018
    Co-Authors: Alexander Foden, David M Collins, A J Wilkinson, T B Britton
    Abstract:

    Electron backscatter diffraction (EBSD) is a well-established method of characterisation for Crystalline materials. This technique can rapidly acquire and index diffraction patterns to provide phase and orientation information about the Crystals on the material surface. The conventional analysis method uses signal processing based on a Hough/Radon transform to index each diffraction pattern. This method is limited to the analysis of simple geometric features and ignores subtle characteristics of diffraction patterns, such as variations in relative band intensities. A second method, developed to address the shortcomings of the Hough/Radon transform, is based on template matching of a test experimental pattern with a large library of potential patterns. In the present work, the template matching approach has been refined with a new cross correlation function that allows for a smaller library and enables a dramatic speed up in pattern indexing. Refinement of the indexed orientation is performed with a follow-up step to allow for small alterations to the best match from the library search. The orientation is further refined with rapid measurement of misorientation using whole pattern matching. The refined template matching approach is shown to be comparable in accuracy, precision and sensitivity to the Hough based method, even exceeding it in some cases, via the use of simulations and experimental data collected from a Silicon Single Crystal and a deformed {\alpha}-iron sample. The drastic speed up and pattern refinement approaches should increase the widespread utility of pattern matching approaches.