scholarly journals Mathematical Tools that Connect Different Indexing Analyses

Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 8
Author(s):  
Ryoko Oishi-Tomiyasu
Keyword(s):  
Powder Diffraction ◽  
Figure Of Merit ◽  
Electron Backscatter Diffraction ◽  
Higher Dimensions ◽  
Bravais Lattice ◽  
Mathematical Framework ◽  
Electron Backscatter ◽  
Different Types ◽  
2D Data ◽  
Backscatter Diffraction

As mathematical tools that can be commonly used for indexing analyses from different types of experimental patterns, we have recently developed (i) rules on forbidden hkl’s that can be used even when the space group and setting are unknown, (ii) an algorithm for error-stable Bravais lattice determination, (iii) generalization of the de Wolff figure of merit for powder diffraction (1D data) to data in higher-dimensions such as Kikuchi patterns (2D data) by electron backscatter diffraction (EBSD). In particular, (ii) could be used in a variety of situations, not just for indexing. It is explained how (i)–(iii) are used in the mathematical framework of our indexing algorithms.

scholarly journals Analysis of Strain Partitioning in Intercritically Deformed Microstructures via Interrupted Tensile Tests

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 112
Author(s):  
Unai Mayo ◽  
Nerea Isasti ◽  
José M. Rodríguez-Ibabe ◽  
Pello Uranga
Keyword(s):  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Correlation Technique ◽  
Strain Partitioning ◽  
High Angle ◽  
Electron Backscatter ◽  
Different Types ◽  
Final Deformation ◽  
Micro Alloyed Steel ◽  
Backscatter Diffraction

Intercritically deformed steels present combinations of different types of ferrite, such as deformed ferrite (DF) and non-deformed ferrite (NDF) grains, which are transformed during the final deformation passes and final cooling step. Recently, a grain identification and correlation technique based on EBSD has been employed together with a discretization methodology, enabling a distinction to be drawn between different ferrite populations (NDF and DF grains). This paper presents a combination of interrupted tensile tests with crystallographic characterization performed by means of Electron Backscatter Diffraction (EBSD), by analyzing the evolution of an intercritically deformed micro-alloyed steel. In addition to this, and using the nanoindentation technique, both ferrite families were characterized micromechanically and the nanohardness was quantified for each population. NDF grains are softer than DF ones, which is related to the presence of a lower fraction of low-angle grain boundaries. The interrupted tensile tests show the different behavior of low- and high-angle grain boundary evolution as well as the strain partitioning in each ferrite family. NDF population accommodates most of the deformation at initial strain intervals, since strain reaches 10%. For higher strains, NDF and DF grains behave similarly to the strain applied.

scholarly journals Optimizing Electron Backscatter Diffraction of Carbonate Biominerals—Resin Type and Carbon Coating

2009 ◽  
Vol 15 (3) ◽  
pp. 197-203 ◽  
Author(s):  
Alberto Pérez-Huerta ◽  
Maggie Cusack
Keyword(s):  
Carbon Coating ◽  
Blue Mussel ◽  
Electron Backscatter Diffraction ◽  
Diffraction Intensity ◽  
Ebsd Data ◽  
Electron Backscatter ◽  
Different Types ◽  
The Common ◽  
Biogenic Carbonates ◽  
Backscatter Diffraction

AbstractElectron backscatter diffraction (EBSD) is becoming a widely used technique to determine crystallographic orientation in biogenic carbonates. Despite this use, there is little information available on preparation for the analysis of biogenic carbonates. EBSD data are compared for biogenic aragonite and calcite in the common blue mussel, Mytilus edulis, using different types of resin and thicknesses of carbon coating. Results indicate that carbonate biomineral samples provide better EBSD results if they are embedded in resin, particularly epoxy resin. A uniform layer of carbon of 2.5 nm thickness provides sufficient conductivity for EBSD analyses of such insulators to avoid charging without masking the diffracted signal. Diffraction intensity decreases with carbon coating thickness of 5 nm or more. This study demonstrates the importance of optimizing sample preparation for EBSD analyses of insulators such as carbonate biominerals.

scholarly journals Dislocation Creep of Olivine and Amphibole in Amphibole Peridotites from Åheim, Norway

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1018
Author(s):  
Sejin Jung ◽  
Takafumi Yamamoto ◽  
Jun-ichi Ando ◽  
Haemyeong Jung
Keyword(s):  
Electron Microscopy ◽  
Slip System ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Dislocation Creep ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Different Types ◽  
Localized Shear Deformation ◽  
Backscatter Diffraction

Amphibole peridotite samples from Åheim, Norway, were analyzed to understand the deformation mechanism and microstructural evolution of olivine and amphibole through the Scandian Orogeny and subsequent exhumation process. Three Åheim amphibole peridotite samples were selected for detailed microstructural analysis. The Åheim amphibole peridotites exhibit porphyroclastic texture, abundant subgrain boundaries in olivine, and the evidence of localized shear deformation in the tremolite-rich layer. Two different types of olivine lattice preferred orientations (LPOs) were observed: B- and A-type LPOs. Electron backscatter diffraction (EBSD) mapping and transmission electron microscopy (TEM) observations revealed that most subgrain boundaries in olivine consist of dislocations with a (001)[100] slip system. The subgrain boundaries in olivine may have resulted from the deformation of olivine with moderate water content. In addition, TEM observations using a thickness-fringe method showed that the free dislocations of olivine with the (010)[100] slip system were dominant in the peridotites. Our data suggest that the subgrain boundaries and free dislocations in olivine represent a product of later-stage deformation associated with the exhumation process. EBSD mapping of the tremolite-rich layer revealed intracrystalline plasticity in amphibole, which can be interpreted as the activation of the (100)[001] slip system.

Determining the Bravais lattice using a single electron backscatter diffraction pattern

2015 ◽  
Vol 48 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Lili Li ◽  
Ming Han
Keyword(s):  
Electron Backscatter Diffraction ◽  
A Priori ◽  
Single Electron ◽  
Bravais Lattice ◽  
Cell Parameters ◽  
Mineral Sample ◽  
Electron Backscatter ◽  
Ebsd Pattern ◽  
Backscatter Diffraction

Theab initioderivation of the Bravais lattice from the Kikuchi bands detected from a single electron backscatter diffraction (EBSD) pattern is successfully performed. The as-measured band widths and azimuths always suffer from gnomonic distortions which need to be corrected. A primitive reciprocal cell is first reconstructed by means of the corrected data and the cell parameters are then refined by least-squares analysis of hugely over-determined equations. This allows one to further derive a Niggli reduced cell from the primitive cell. The algorithm presented is not related to any crystal symmetry information and is therefore applicable to all crystal systems. The feasibility of the determination of the Bravais lattice type and parameters from a single EBSD pattern is demonstrated using a mineral sample without anya prioriinformation about its crystal structure. The novel application developed in the present work opens the way to the determination of the Bravais lattice of crystalline materials using scanning electron microscopy combined with the EBSD technique.

scholarly journals Twinning in SnO2-based ceramics doped with CoO and Nb2O5: morphology of multiple twins revealed by electron backscatter diffraction

2020 ◽  
Vol 76 (5) ◽  
pp. 875-883
Author(s):  
José Alberto Padrón-Navarta ◽  
Fabrice Barou ◽  
Nina Daneu
Keyword(s):  
Solid State ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Automated Identification ◽  
Twin Domain ◽  
Electron Backscatter ◽  
Different Types ◽  
Average Size ◽  
Grain Misorientation ◽  
Backscatter Diffraction

Electron backscatter diffraction (EBSD) was used for the analysis of multiple cyclic twins in cassiterite (SnO2), which form during sintering of SnO2 with small additions of CoO and Nb2O5. Grain misorientation analysis has shown that about one third of all grains contain {101} twin boundaries (TBs). The majority of these grains are contact twins, whereas a small fraction of grains are multiple, mainly cyclic twins. A procedure was developed in MTEX [Bachmann, Hielscher & Schaeben (2010). Solid State Phenom. 160, 63–88] for automated identification of crystallographically different types of cyclic twins and found two main types: coplanar twins composed of three or four domains with a common [010] axis and alternating twins composed of three to seven domains oriented along the [111] axis. Both types of cyclic twins have a characteristic common origin (nucleus) of all TBs, which is positioned eccentric relative to the grain section and the cycle is closed with a shorter non-crystallographic contact between the first and the last twin domain. The morphology of cyclic twins suggests that they form by nucleation in the initial stages of grain growth. The average size of twinned grains increases with the number of twin domains indicating the influence of TBs formation on the growth of composite grains.

Distribution rules of systematic absences and generalized de Wolff figures of merit applied to electron backscatter diffraction ab initio indexing

2021 ◽  
Vol 54 (2) ◽  
pp. 624-635
Author(s):  
Ryoko Oishi-Tomiyasu ◽  
Tomohito Tanaka ◽  
Jun'ichi Nakagawa
Keyword(s):  
Ab Initio ◽  
Electron Backscatter Diffraction ◽  
Negative Influence ◽  
Bravais Lattice ◽  
Cell Parameters ◽  
Figures Of Merit ◽  
Distribution Rules ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Orientation Determination

A new method for electron backscatter diffraction ab initio indexing is reported that adopts several methods originally invented for powder indexing. Distribution rules of systematic absences and error-stable Bravais lattice determination are used to eliminate the negative influence of non-visible bands and erroneous information from visible bands. In addition, generalized versions of the de Wolff figures of merit are proposed as a new sorting criterion for the obtained unit-cell parameters, which can be used in both orientation determination and ab initio indexing from Kikuchi patterns. Computational results show that the new figures of merit work well, similar to the original de Wolff Mn . The ambiguity of the indexing solutions is also pointed out, which happens in particular for low-symmetry cells and may generate multiple distinct solutions even if very accurate positions of band centre lines and the projection centre are given. It is supposed that this is the reason why indexing was successful in an orthorhombic case but not in a triclinic cell.

EBSDL: a computer program for determining an unknown Bravais lattice using a single electron backscatter diffraction pattern

2014 ◽  
Vol 47 (4) ◽  
pp. 1466-1468 ◽  
Author(s):  
Lili Li ◽  
Sheng Ouyang ◽  
Yanqing Yang ◽  
Ming Han
Keyword(s):  
Computer Program ◽  
Electron Backscatter Diffraction ◽  
Bravais Lattice ◽  
Chemical Information ◽  
Phase Identification ◽  
Crystalline Materials ◽  
The Poor ◽  
Electron Backscatter ◽  
Ebsd Pattern ◽  
Backscatter Diffraction

Electron backscatter diffraction (EBSD) patterns provide a wealth of crystallographic information but disappointingly low accuracy. Adopting a strategy of compensating the poor accuracy by the large amount of information, a computer program, EBSDL, has been successfully developed to determine the unknown Bravais lattice of bulk crystalline materials using a single EBSD pattern. Unlike programs that perform phase identification, the new application is completely independent of chemical information.

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