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Pai N, Manda S, Sudhalkar B, Syphus B, Fullwood D, de Kloe R, Wright S, Patra A, Samajdar I. Diffraction-Based Multiscale Residual Strain Measurements. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024; 30:236-252. [PMID: 38447180 DOI: 10.1093/mam/ozae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/29/2023] [Accepted: 02/11/2024] [Indexed: 03/08/2024]
Abstract
Modern analytical tools, from microfocus X-ray diffraction (XRD) to electron microscopy-based microtexture measurements, offer exciting possibilities of diffraction-based multiscale residual strain measurements. The different techniques differ in scale and resolution, but may also yield significantly different strain values. This study, for example, clearly established that high-resolution electron backscattered diffraction (HR-EBSD) and high-resolution transmission Kikuchi diffraction (HR-TKD) [sensitive to changes in interplanar angle (Δθθ)], provide quantitatively higher residual strains than micro-Laue XRD and transmission electron microscope (TEM) based precession electron diffraction (PED) [sensitive to changes in interplanar spacing (Δdd)]. Even after correcting key known factors affecting the accuracy of HR-EBSD strain measurements, a scaling factor of ∼1.57 (between HR-EBSD and micro-Laue) emerged. We have then conducted "virtual" experiments by systematically deforming an ideal lattice by either changing an interplanar angle (α) or a lattice parameter (a). The patterns were kinematically and dynamically simulated, and corresponding strains were measured by HR-EBSD. These strains showed consistently higher values for lattice(s) distorted by α, than those altered by a. The differences in strain measurements were further emphasized by mapping identical location with HR-TKD and TEM-PED. These measurements exhibited different spatial resolution, but when scaled (with ∼1.57) provided similar lattice distortions numerically.
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Affiliation(s)
- Namit Pai
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Sanjay Manda
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Bhargav Sudhalkar
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Bethany Syphus
- Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - David Fullwood
- Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - René de Kloe
- Gatan-Edax, Ringbaan Noord 103, 5046 AA Tilburg, The Netherlands
| | - Stuart Wright
- Gatan-Edax, 5794 W. Las Positas Blvd., Pleasanton, CA 94588, USA
| | - Anirban Patra
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Indradev Samajdar
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076, India
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Tokarski T, Nolze G, Winkelmann A, Rychłowski Ł, Bała P, Cios G. Transmission Kikuchi diffraction: The impact of the signal-to-noise ratio. Ultramicroscopy 2021; 230:113372. [PMID: 34479040 DOI: 10.1016/j.ultramic.2021.113372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/27/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Signal optimization for transmission Kikuchi diffraction (TKD) measurements in the scanning electron microscope is investigated by a comparison of different sample holder designs. An optimized design is presented, which uses a metal shield to efficiently trap the electron beam after transmission through the sample. For comparison, a second holder configuration allows a significant number of the transmitted electrons to scatter back from the surface of the sample holder onto the diffraction camera screen. It is shown that the secondary interaction with the sample holder leads to a significant increase in the background level, as well as to additional noise in the final Kikuchi diffraction signal. The clean TKD signal of the optimized holder design with reduced background scattering makes it possible to use small signal changes in the range of 2% of the camera full dynamic range. As is shown by an analysis of the power spectrum, the signal-to-noise ratio in the processed Kikuchi diffraction patterns is improved by an order of magnitude. As a result, the optimized design allows an increase in pattern signal to noise ratio which may lead to increase in measurement speed and indexing reliability.
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Affiliation(s)
- Tomasz Tokarski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Gert Nolze
- Federal Institute for Materials, Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Aimo Winkelmann
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Łukasz Rychłowski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Piotr Bała
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland; Faculty of Metals and Industrial Computer Science, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Grzegorz Cios
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
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Winkelmann A, Nolze G, Cios G, Tokarski T, Bała P, Hourahine B, Trager-Cowan C. Kikuchi pattern simulations of backscattered and transmitted electrons. J Microsc 2021; 284:157-184. [PMID: 34275156 DOI: 10.1111/jmi.13051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/15/2021] [Indexed: 11/29/2022]
Abstract
We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKD can be affected by changes in the order of 10 - 3 - 10 - 2 if excess-deficiency features are not considered in the theoretical model underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer from biases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model.
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Affiliation(s)
- Aimo Winkelmann
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Kraków, Poland.,Department of Physics, SUPA, University of Strathclyde, Glasgow, UK
| | - Gert Nolze
- Federal Institute for Materials, Research and Testing (BAM), Berlin, Germany.,TU Bergakademie Freiberg, Institute for Mineralogy, Freiberg, Germany
| | - Grzegorz Cios
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Kraków, Poland
| | - Tomasz Tokarski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Kraków, Poland
| | - Piotr Bała
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Kraków, Poland
| | - Ben Hourahine
- Department of Physics, SUPA, University of Strathclyde, Glasgow, UK
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Jeong J, Jang WS, Kim KH, Kostka A, Gu G, Kim YM, Oh SH. Crystallographic Orientation Analysis of Nanocrystalline Tungsten Thin Film Using TEM Precession Electron Diffraction and SEM Transmission Kikuchi Diffraction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:237-249. [PMID: 33541465 DOI: 10.1017/s1431927621000027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two advanced, automated crystal orientation mapping techniques suited for nanocrystalline materials—precession electron diffraction (PED) in transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) in scanning electron microscopy (SEM)—are evaluated by comparing the orientation maps obtained from the identical location on a 30 nm-thick nanocrystalline tungsten (W) thin film. A side-by-side comparison of the orientation maps directly showed that the large-scale orientation features are almost identical. However, there are differences in the fine details, which arise from the fundamentally different nature of the spot pattern and Kikuchi line pattern in terms of the excitation volume and the angular resolution. While TEM-PED is more reliable to characterize grains oriented along low-index zone axes, the high angular resolution of SEM-TKD allows the detection of small misorientation between grains and thus yields better quantification and statistical analysis of grain orientation. Given that both TEM-PED and SEM-TKD orientation mapping techniques are complementary tools for nanocrystalline materials, one can be favorably selected depending on the requirements of the analysis, as they have competitive performance in terms of angular resolution and texture quantification.
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Affiliation(s)
- Jiwon Jeong
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon16419, Republic of Korea
- Max-Planck Institut für Eisenforschung GmbH, Düsseldorf40237, Germany
| | - Woo-Sung Jang
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon16419, Republic of Korea
| | - Kwang Hun Kim
- Memory Analysis Science & Engineering Group, Samsung Electronics, Hwasung18448, Republic of Korea
| | - Aleksander Kostka
- Zentrum für Grenzflächendominierte Höchstleistungswerkstoffe (ZGH), Ruhr-Universität Bochum, Bochum44801, Germany
| | - Gilho Gu
- Memory Analysis Science & Engineering Group, Samsung Electronics, Hwasung18448, Republic of Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon16419, Republic of Korea
| | - Sang Ho Oh
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon16419, Republic of Korea
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Spatial Resolutions of On-Axis and Off-Axis Transmission Kikuchi Diffraction Methods. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9214478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spatial resolution is one of the key factors in orientation microscopy, as it determines the accuracy of grain size investigation and phase identification. We determined the spatial resolutions of on-axis and off-axis transmission Kikuchi diffraction (TKD) methods by calculating correlation coefficients using only the effective parts of on-axis and off-axis transmission Kikuchi patterns. During the calculation, we used average filtering to evaluate the spatial resolution more accurately. The spatial resolutions of both on-axis and off-axis TKD methods were determined in the same scanning electron microscope at different accelerating voltages and specimen thicknesses. The spatial resolution of the on-axis TKD was higher than that of the off-axis TKD at the same parameters. Furthermore, with an increase in accelerating voltage or a decrease in specimen thickness, the spatial resolutions of the two configurations could be significantly improved, from tens of nanometers to below 10 nm. At a voltage of 30 kV and sample thickness of 74 nm, both on-axis and off-axis TKD methods exhibited the highest resolutions of 6.2 and 9.7 nm, respectively.
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Liu J, Lozano-Perez S, Wilkinson AJ, Grovenor CRM. On the depth resolution of transmission Kikuchi diffraction (TKD) analysis. Ultramicroscopy 2019; 205:5-12. [PMID: 31234103 DOI: 10.1016/j.ultramic.2019.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/26/2019] [Accepted: 06/09/2019] [Indexed: 10/26/2022]
Abstract
In this paper, we have analyzed the depth resolution that can be achieved by on-axis transmission Kikuchi diffraction (TKD) using a Zr-Nb alloy. The results indicate that the signals contributing to detectable Kikuchi bands originate from a depth of approximately the mean free path of thermal diffuse scattering (λTDS) from the bottom surface of a thin foil sample. This existing surface sensitivity can thus lead to the observation of different grain structures when opposite sides of a nano-crystalline foil are facing the incident electron beam. These results also provide a guideline for the ideal sample thickness for TKD analysis of ≤ 6λTDS, or 21 times the elastic scattering mean free path (λMFP) for samples of high crystal symmetry. For samples of lower symmetry, a smaller thickness ≤ 3λTDS, or ≤ 10λMFP is suggested.
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Affiliation(s)
- Junliang Liu
- Department of Materials, University of Oxford, Parks Road, OX1 3PH, United Kingdom.
| | - Sergio Lozano-Perez
- Department of Materials, University of Oxford, Parks Road, OX1 3PH, United Kingdom
| | - Angus J Wilkinson
- Department of Materials, University of Oxford, Parks Road, OX1 3PH, United Kingdom
| | - Chris R M Grovenor
- Department of Materials, University of Oxford, Parks Road, OX1 3PH, United Kingdom
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Caplins BW, Holm JD, Keller RR. Transmission imaging with a programmable detector in a scanning electron microscope. Ultramicroscopy 2019; 196:40-48. [DOI: 10.1016/j.ultramic.2018.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
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Brodu E, Bouzy E. Depth Resolution Dependence on Sample Thickness and Incident Energy in On-Axis Transmission Kikuchi Diffraction in Scanning Electron Microscope (SEM). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:1096-1106. [PMID: 29282164 DOI: 10.1017/s1431927617012697] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transmission Kikuchi diffraction is an emerging technique aimed at producing orientation maps of the structure of materials with a nanometric lateral resolution. This study investigates experimentally the depth resolution of the on-axis configuration, via a twinned silicon bi-crystal sample specifically designed and fabricated. The measured depth resolution varies from 30 to 65 nm in the range 10-30 keV, with a close to linear dependence with incident energy and no dependence with the total sample thickness. The depth resolution is explained in terms of two mechanisms acting concomitantly: generation of Kikuchi diffraction all along the thickness of the sample, associated with continuous absorption on the way out. A model based on the electron mean free path is used to account for the dependence with incident energy of the depth resolution. In addition, based on the results in silicon, the use of the mean absorption coefficient is proposed to predict the depth resolution for any atomic number and incident energy.
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Affiliation(s)
- Etienne Brodu
- 1Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3),UMR CNRS 7239,Université de Lorraine,57045 Metz,France
| | - Emmanuel Bouzy
- 1Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3),UMR CNRS 7239,Université de Lorraine,57045 Metz,France
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