• Title, Summary, Keyword: electron backscatter diffraction(EBSD)

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Analysis of Twin in Mg Alloys Using Electron Backscatter Diffraction Technique

  • Lee, Jong Youn;Kim, Won Tae;Kim, Do Hyang
    • Applied Microscopy
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    • v.44 no.1
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    • pp.34-39
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    • 2014
  • Electron backscatter diffraction (EBSD) is widely used for quantitative microstructural analysis of the crystallographic nature of variety of materials such as metals, minerals, and ceramics. EBSD can provide a wide range of information on materials including grain size, grain orientation, texture, and phase identity. In the case of metallic alloys, EBSD now has become an essential technique to analyze the texture, particularly when severe deformation is applied to the alloys. In addition, EBSD can be one of the very useful tools in identification of twin, particularly in Mg alloys. In Mg alloys different type of twin can occur depending on the c/a ratio and stacking fault energy on the twinning plane. Such an occurrence of different type of twin can be most effectively analyzed using EBSD technique. In this article, the recent development of Mg alloys and occurrence of twin in Mg are reviewed. Then, recently published example for identification of tension and compression twins in AZ31 and ZX31 is introduced to explain how EBSD can be used for identification of twin in Mg.

A Correlative Approach for Identifying Complex Phases by Electron Backscatter Diffraction and Transmission Electron Microscopy

  • Na, Seon-Hyeong;Seol, Jae-Bok;Jafari, Majid;Park, Chan-Gyung
    • Applied Microscopy
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    • v.47 no.1
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    • pp.43-49
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    • 2017
  • A new method was introduced to distinguish the ferrite, bainite and martensite in transformation induced plasticity (TRIP) steel by using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). EBSD is a very powerful microstructure analysis technique at the length scales ranging from tens of nanometers to millimeters. However, iron BCC phases such as ferrite, bainite and martensite cannot be easily distinguished by EBSD due to their similar surface morphology and crystallographic structure. Among the various EBSD-based methodology, image quality (IQ) values, which present the perfection of a crystal lattice, was used to distinguish the iron BCC phases. IQ values are very useful tools to discern the iron BCC phases because of their different density of crystal defect and lattice distortion. However, there are still remaining problems that make the separation of bainite and martensite difficult. For instance, these phases have very similar IQ values in many cases, especially in deformed region; therefore, even though the IQ value was used, it has been difficult to distinguish the bainite and martensite. For more precise separation of bainite and martensite, IQ threshold values were determined by a correlative TEM analysis. By determining the threshold values, iron BCC phases were successfully separated.

Texture Characteristics of TiN Film by Electron Backscatter Diffraction

  • Jeong, Bong-Yong
    • Korean Journal of Metals and Materials
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    • v.50 no.12
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    • pp.867-871
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    • 2012
  • The microstructure and texture of TiN coatings on a Ni-based super-alloy were characterized by the automated version of electron backscatter diffraction (EBSD), EBSD techniques were used to investigate the very fine TiN grain shape and crystal orientation. This study confirmed that EBSD techniques provide a very useful tool for characterization of coating materials. The TiN grains had a special texture, a {001}-fiber texture in the coating layer. It was also found that, in severe environments, the coating performance of equiaxial and randomly oriented TiN is superior to that with columnar structures.

Characterization of Two-Dimensional Transition Metal Dichalcogenides in the Scanning Electron Microscope Using Energy Dispersive X-ray Spectrometry, Electron Backscatter Diffraction, and Atomic Force Microscopy

  • Lang, Christian;Hiscock, Matthew;Larsen, Kim;Moffat, Jonathan;Sundaram, Ravi
    • Applied Microscopy
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    • v.45 no.3
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    • pp.131-134
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    • 2015
  • Here we show how by processing energy dispersive X-ray spectrometry (EDS) data obtained using highly sensitive, new generation EDS detectors in the AZtec LayerProbe software we can obtain data of sufficiently high quality to non-destructively measure the number of layers in two-dimensional (2D) $MoS_2$ and $MoS_2/WSe_2$ and thereby enable the characterization of working devices based on 2D materials. We compare the thickness measurements with EDS to results from atomic force microscopy measurements. We also show how we can use electron backscatter diffraction (EBSD) to address fabrication challenges of 2D materials. Results from EBSD analysis of individual flakes of exfoliated $MoS_2$ obtained using the Nordlys Nano detector are shown to aid a better understanding of the exfoliation process which is still widely used to produce 2D materials for research purposes.

Technical Investigation into the In-situ Electron Backscatter Diffraction Analysis for the Recrystallization Study on Extra Low Carbon Steels

  • Kim, Ju-Heon;Kim, Dong-Ik;Kim, Jong Seok;Choi, Shi-Hoon;Yi, Kyung-Woo;Oh, Kyu Hwan
    • Applied Microscopy
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    • v.43 no.2
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    • pp.88-97
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    • 2013
  • Technical investigation to figure out the problems arising during in-situ heating electron backscatter diffraction (EBSD) analysis inside scanning electron microscopy (SEM) was carried out. EBSD patterns were successfully acquired up to $830^{\circ}C$ without degradation of EBSD pattern quality in steels. Several technical problems such as image drift and surface microstructure pinning were taking place during in-situ experiments. Image drift problem was successfully prevented in constant current supplying mode. It was revealed that the surface pinning problem was resulted from the $TiO_2$ oxide particle formation during heating inside SEM chamber. Surface pinning phenomenon was fairly reduced by additional platinum and carbon multi-layer coating before in-situ heating experiment, furthermore was perfectly prevented by improvement of vacuum level of SEM chamber via leakage control. Plane view in-situ observation provides better understanding on the overall feature of recrystallization phenomena and cross sectional in-situ observation provides clearer understanding on the recrystallization mechanism.

A Study on the Surface Characteristics of Dual Phase Steel by Electron Backscatter Diffraction (EBSD) Technique

  • Jeong, Bong-Yong;Ryou, Min;Lee, Chongmu;Kim, Myung Ho
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.1
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    • pp.20-23
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    • 2014
  • Dual phase steels have a microstructure comprising of a polygonal ferrite matrix together with dispersed islands of martensite. There are clear differences between the image quality (IQ) map of the dual phase and the corresponding ferritic/pearlitic structures, both in the as-heat treated and cold rolled conditions. Electron backscatter diffraction (EBSD) techniques were used to study the evolution substructure of steel due to plastic deformation. The martensite-ferrite and ferrite-pearlite interfaces were observed. The interface can be a source of mobile dislocations which the bands seem to originate from the martensite islands. In particular, the use of image quality is highlighted.

Microstructure Characteristics and Identification of Low-Carbon Steels Fabricated by Controlled Rolling and Accelerated Cooling Processes (제어 압연과 가속 냉각에 의해 저탄소강에서 형성되는 미세조직의 특징과 구분)

  • Lee, Sang-In;Hong, Tae-Woon;Hwang, Byoungchul
    • Korean Journal of Materials Research
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    • v.27 no.11
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    • pp.636-642
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    • 2017
  • In the present study the microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes was characterized and identified based on various microstructure analysis methods including optical and scanning electron microscopy, and electron backscatter diffraction(EBSD). Although low-carbon steels are usually composed of ${\alpha}-ferrite$ and cementite($Fe_3C$) phases, they can have complex microstructures consisting of ferrites with different size, morphology, and dislocation density, and secondary phases dependent on rolling and accelerated cooling conditions. The microstructure of low-carbon steels investigated in this study was basically classified into polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite based on the inverse pole figure, image quality, grain boundary, kernel average misorientation(KAM), and grain orientation spread(GOS) maps, obtained from EBSD analysis. From these results, it can be said that the EBSD analysis provides a valuable tool to identify and quantify the complex microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes.

Three-Dimensional Automated Crystal Orientation and Phase Mapping Analysis of Epitaxially Grown Thin Film Interfaces by Using Transmission Electron Microscopy

  • Kim, Chang-Yeon;Lee, Ji-Hyun;Yoo, Seung Jo;Lee, Seok-Hoon;Kim, Jin-Gyu
    • Applied Microscopy
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    • v.45 no.3
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    • pp.183-188
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    • 2015
  • Due to the miniaturization of semiconductor devices, their crystal structure on the nanoscale must be analyzed. However, scanning electron microscope-electron backscatter diffraction (EBSD) has a limitation of resolution in nanoscale and high-resolution electron microscopy (HREM) can be used to analyze restrictive local structural information. In this study, three-dimensional (3D) automated crystal orientation and phase mapping using transmission electron microscopy (TEM) (3D TEM-EBSD) was used to identify the crystal structure relationship between an epitaxially grown CdS interfacial layer and a $Cu(In_xGa_{x-1})Se_2$ (CIGS) solar cell layer. The 3D TEM-EBSD technique clearly defined the crystal orientation and phase of the epitaxially grown layers, making it useful for establishing the growth mechanism of functional nano-materials.

Grain Size Determination of Copper Film by Electron Backscatter Diffraction (EBSD를 이용한 구리박막의 결정립 크기 결정)

  • Kim, Su-Hyeon;Kang, Joo-Hee;Han, Seung Zeon
    • Korean Journal of Metals and Materials
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    • v.48 no.9
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    • pp.847-855
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    • 2010
  • The grain size of a cross-section of $8{\mu}m$-thick copper film was determined by electron backscatter diffraction analysis. Grain size distribution histogram showed the presence of a large fraction of small-sized grains, and the mean grain size was significantly affected by handling of them. A cut-off grain size, below which all grains are ignored as noise and eliminated for the calculation of the mean value, should be three or four times as large as the step size. Due to the presence of small grains, the linear intercept method derived larger mean grain size, which depends less sensitively on the cut-off grain size than the equivalent circle diameter method.