1
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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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2
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Zhang T, Britton TB. Multi-exposure diffraction pattern fusion applied to enable wider-angle transmission Kikuchi diffraction with direct electron detectors. Ultramicroscopy 2024; 257:113902. [PMID: 38086289 DOI: 10.1016/j.ultramic.2023.113902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 10/27/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
Diffraction pattern analysis can be used to reveal the crystalline structure of materials, and this information is used to nano- and micro-structure of advanced engineering materials that enable modern life. For nano-structured materials typically diffraction pattern analysis is performed in the transmission electron microscope (TEM) and TEM diffraction patterns typically have a limited angular range (less than a few degrees) due to the long camera length, and this requires analysis of multiple patterns to probe a unit cell. As a different approach, wide angle Kikuchi patterns can be captured using an on-axis detector in the scanning electron microscope (SEM) with a shorter camera length. These 'transmission Kikuchi diffraction' (TKD) patterns present a direct projection of the unit cell and can be routinely analysed using EBSD-based methods and dynamical diffraction theory. In the present work, we enhance this analysis significantly and present a multi-exposure diffraction pattern fusion method that increases the dynamic range of the detected patterns captured with a Timepix3-based direct electron detector (DED). This method uses an easy-to-apply exposure fusion routine to collect data and extend the dynamic range, as well as normalise the intensity distribution within these very wide (>95°) angle patterns. The potential of this method is demonstrated with full diffraction sphere reprojection and highlight potential of the approach to rapidly probe the structure of nano-structured materials in the scanning electron microscope.
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Affiliation(s)
- Tianbi Zhang
- Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 Canada
| | - T Ben Britton
- Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 Canada.
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3
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Jiang Q, Chen Y, Shuai Q, Liu F, Li L, He C, Zhang H, Wang C, Liu Y, Wang Q. Fatigue-Induced HCP-to-FCC Phase Transformation Resulting in Two FCC-Zr Variants in Pure Zirconium. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6215. [PMID: 37763494 PMCID: PMC10532661 DOI: 10.3390/ma16186215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023]
Abstract
This study utilized transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) to investigate the fatigue-induced HCP-to-FCC phase transformation in industrial pure zirconium under a stress ratio of R = 0.1. The results show that fatigue damages result from phase deformations during cyclic loadings. The fatigue-induced FCC-Zr phases exhibit a B-type orientation relationship with the HCP-Zr matrix. Notedly, due to the different growth directions of Shockley partial dislocations relative to nucleation points, there are two FCC-Zr variants after the HCP-to-FCC phase transformation. The content of these two variants accounts for 65% and 35% of the total FCC-Zr, respectively, appearing as lamellae morphology embedded parallelly within the matrix. The distribution of the two variants includes isolated distribution and adjacent distribution. For the adjacent distribution, a twinning relationship is observed between the two variants. Meanwhile, as an intermediate transition stage of the HCP-to-FCC phase transformation, stacking faults are observed at the boundaries of the FCC-Zr lamellae. These findings offer insights into the microstructural features and formation mechanisms of fatigue-induced HCP-to-FCC phase transformation.
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Affiliation(s)
- Qing Jiang
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yao Chen
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Qi Shuai
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Fulin Liu
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Lang Li
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Chao He
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Hong Zhang
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Chong Wang
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Yongjie Liu
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Qingyuan Wang
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
- Institute for Advanced Study, Chengdu University, Chengdu 610106, China
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4
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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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5
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Karamched PS, Saravanan N, Haley JC, Wilkinson AJ, Lozano-Perez S. Effect of sample thinning on strains and lattice rotations measured from Transmission Kikuchi diffraction in the SEM. Ultramicroscopy 2021; 225:113267. [PMID: 33878702 DOI: 10.1016/j.ultramic.2021.113267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 12/18/2020] [Accepted: 03/24/2021] [Indexed: 11/16/2022]
Abstract
Cross correlation based high angular resolution EBSD (or HR-EBSD) has been developed for measurement of elastic strains, lattice rotations (and estimating GND density). Recent advances in Transmission Kikuchi diffraction (TKD), especially the on-axis geometry allows the possibility of acquiring patterns at higher spatial resolution. However, some controversy remains as to whether stresses/strains measured after the sample thinning process are still representative of the bulk sample. In this paper, we explore a way of applying the HR-EBSD method to study strains and lattice rotations in an initially bulk sample, that is then progressively thinned down until a similar analysis can be performed on thin (and electron transparent) samples. Thus, HR-TKD will be compared as a possible alternative to HR-EBSD, in scenarios when it is not always possible to perform EBSD on the surface of the sample. An estimate of strain relaxation in the sample as a result of sample thinning is presented.
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Affiliation(s)
- Phani S Karamched
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom.
| | - Naganand Saravanan
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jack C Haley
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Angus J Wilkinson
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Sergio Lozano-Perez
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
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6
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Chou SW, Yang YY, Lin CY, Goran D, Chou KC, Chou PT. Boost reactivity of tri-iodide reduction electrode by highly faceted octahedral PtNi nanocrystals. J Catal 2021. [DOI: 10.1016/j.jcat.2021.02.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Sugar JD, McKeown JT, Banga D, Michael JR. Comparison of Orientation Mapping in SEM and TEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:630-640. [PMID: 32583757 DOI: 10.1017/s1431927620001671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multiple experimental configurations for performing nanoscale orientation mapping are compared to determine their fidelity to the true microstructure of a sample. Transmission Kikuchi diffraction (TKD) experiments in a scanning electron microscope (SEM) and nanobeam diffraction (NBD) experiments in a transmission electron microscope (TEM) were performed on thin electrodeposited hard Au films with two different microstructures. The Au samples either had a grain size that is >50 or <20 nm. The same regions of the samples were measured with TKD apparatuses at 30 kV in an SEM with detectors in the horizontal and vertical configurations and in the TEM at 300 kV. Under the proper conditions, we demonstrate that all three configurations can produce data of equivalent quality. Each method has strengths and challenges associated with its application and representation of the true microstructure. The conditions needed to obtain high-quality data for each acquisition method and the challenges associated with each are discussed.
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Affiliation(s)
| | | | - Dhego Banga
- Sandia National Laboratories, Livermore, CA94550, USA
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8
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Mariano R, Yau A, McKeown JT, Kumar M, Kanan MW. Comparing Scanning Electron Microscope and Transmission Electron Microscope Grain Mapping Techniques Applied to Well-Defined and Highly Irregular Nanoparticles. ACS OMEGA 2020; 5:2791-2799. [PMID: 32095702 PMCID: PMC7033971 DOI: 10.1021/acsomega.9b03505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
Investigating how grain structure affects the functional properties of nanoparticles requires a robust method for nanoscale grain mapping. In this study, we directly compare the grain mapping ability of transmission Kikuchi diffraction (TKD) in a scanning electron microscope to automated crystal orientation mapping (ACOM) in a transmission electron microscope across multiple nanoparticle materials. Analysis of well-defined Au, ZnO, and ZnSe nanoparticles showed that the grain orientations and GB geometries obtained by TKD are accurate and match those obtained by ACOM. For more complex polycrystalline Cu nanostructures, TKD provided an interpretable grain map whereas ACOM, with or without precession electron diffraction, yielded speckled, uninterpretable maps with orientation errors. Acquisition times for TKD were generally shorter than those for ACOM. Our results validate the use of TKD for characterizing grain orientation and grain boundary distributions in nanoparticles, providing a framework for the broader exploration of how microstructure influences nanoparticle properties.
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Affiliation(s)
- Ruperto
G. Mariano
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Allison Yau
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Joseph T. McKeown
- Materials
Science Division, Lawrence Livermore National
Laboratory, Livermore, California 94550, United States
| | - Mukul Kumar
- Materials
Engineering Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Matthew W. Kanan
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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9
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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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10
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Fanta ABS, Fuller A, Alimadadi H, Todeschini M, Goran D, Burrows A. Improving the imaging capability of an on-axis transmission Kikuchi detector. Ultramicroscopy 2019; 206:112812. [PMID: 31382231 DOI: 10.1016/j.ultramic.2019.112812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/30/2019] [Accepted: 07/07/2019] [Indexed: 10/26/2022]
Abstract
Transmission Kikuchi Diffraction (TKD) in the scanning electron microscope has been developing at a fast pace since its introduction less than a decade ago. The recently presented on-axis detector configuration, with its optimized geometry, has significantly increased the signal yield and facilitated the acquisition of STEM images in bright field (BF) and dark field (DF) mode, in addition to the automated orientation mapping of nanocrystalline electron transparent samples. However, the physical position of the integrated imaging system, located outside the detector screen, requires its movement in order to combine high resolution STEM images with high resolution orientation measurements. The difference between the two positions makes it impossible to acquire optimal signals simultaneously, leading to challenges when investigating site-specific nanocrystalline microstructures. To eliminate this drawback, a new imaging capability was added at the centre of the on-axis TKD detector, thus enabling acquisition of optimal quality BF images and orientation maps without detector movement. The advantages brought about by this new configuration are presented and the associated limitations are discussed.
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Affiliation(s)
- Alice Bastos S Fanta
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark.
| | - Adam Fuller
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark.
| | - Hossein Alimadadi
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark; Danish Technological Institute, Kongsvang Alle 29, 8000 Aarhus C, Denmark.
| | - Matteo Todeschini
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark; Blue Scientific Ltd., St. John's Innovation Centre, Cowley Road, Cambridge CB4 0WS, UK
| | | | - Andrew Burrows
- DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Fysikvej 307, 2800 Kgs. Lyngby, Denmark; ISS Group Services Ltd, Pellowe House, Francis Road, Withington, Manchester, Greater Manchester M20 4XP, UK
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11
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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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12
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Liang XZ, Dodge MF, Jiang J, Dong HB. Using transmission Kikuchi diffraction in a scanning electron microscope to quantify geometrically necessary dislocation density at the nanoscale. Ultramicroscopy 2018; 197:39-45. [PMID: 30496887 DOI: 10.1016/j.ultramic.2018.11.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 11/26/2022]
Abstract
It is challenging to quantify the geometrically necessary dislocation (GND) density at the nanoscale using conventional electron backscatter diffraction due to its limited spatial resolution. To overcome this problem, in this study, the transmission Kikuchi diffraction (TKD) technique is used to measure lattice orientation and to calculate the corresponding nanoscale GND density. Using the TKD method, a variation of GND density from 6 × 1014 to 1016 m-2 has been measured in a welded super duplex stainless steel sample. The distribution of dislocation density is shown to be in good agreement with transmission electron microscope (TEM) result. Compared with dislocation measurements obtained by TEM, the TKD-GND method is revealed to be a relatively accurate, fast and accessible method.
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Affiliation(s)
- X Z Liang
- Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH, UK; Department of Engineering, Engineering Building, Lancaster University, LA1 4YW, UK.
| | - M F Dodge
- TWI Ltd., Great Abington, Cambridge CB21 6AL, UK.
| | - J Jiang
- Department of Mechanical Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
| | - H B Dong
- Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH, UK.
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