TY - JOUR
A1 - Nolze, Gert
T1 - Euler angles and crystal symmetry
JF - Crystal research and technology
N2 - For the description of (single) crystal orientations, e.g. as measured by electron backscatter diffraction (EBSD) & X-ray diffraction (XRD), Euler angles are still generally used to import and export data. However, because of the lack of standard definitions for the unit cell reference settings and specimen axes, several transformation descriptions exist which produce different sets of Euler angles for the same orientation. There is also no recommended region within the minimal Euler orientation space into which orientations should be placed. This is the reason why different sets of Euler angles for the same orientation are generated by the available software packages for indexing EBSD patterns. These issues are reviewed and addressed.
The influence of crystal symmetry in form of chiral (enantiomorphic) groups is discussed, as well as how multiple, but symmetry-equivalent sets of Euler angles can be reduced in order to deliver a unique orientation description. The Euler coloring algorithms applied to EBSD map data is critically discussed. The specific case of cubic symmetry, especially the effect of the three-fold rotation on the Euler space is investigated in more detail for the highest-symmetric chiral group 432. Recommendations for standard settings of the unit cell to orthogonal coordinate system transformation are given which exploit inherent symmetry.
KW - EBSD
KW - Crystal orientation
KW - Pattern indexing
KW - Subgroup relationship
Y1 - 2015
UR - http://onlinelibrary.wiley.com/doi/10.1002/crat.201400427/full
U6 - http://dx.doi.org/10.1002/crat.201400427
SN - 0023-4753
SN - 1521-4079
SN - 0232-1300
VL - 50
IS - 2
SP - 188
EP - 201
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Grosse, C.
A1 - Winkelmann, Aimo
T1 - Kikuchi pattern analysis of noncentrosymmetric crystals
JF - Journal of applied crystallography
N2 - Different models of Kikuchi pattern formation are compared with respect to their applicability to noncentrosymmetric crystals, and the breakdown of Friedel's rule in experimental electron backscatter diffraction (EBSD) patterns is discussed. Different AIIIBV semiconductor materials are used to evaluate the resulting asymmetry of Kikuchi band profiles for polar lattice planes. By comparison with the characteristic etch pit morphology on a single-crystal surface, the polar character of the measured lattice planes can be assigned absolutely. The presented approach enables point-group-resolved orientation mapping, which goes beyond the commonly applied Laue group analysis in EBSD.
KW - EBSD
KW - Pattern simulation
KW - Point groups
KW - Laue groups
KW - Electron backscatter diffraction
KW - Kikuchi patterns
KW - Enantiomorphy; polarity
KW - Friedel's rule
Y1 - 2015
UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:000362500100006
U6 - http://dx.doi.org/10.1107/S1600576715014016
SN - 0021-8898
SN - 1600-5767
VL - 48
SP - 1405
EP - 1419
PB - Blackwell
CY - Oxford
ER -
TY - JOUR
A1 - Petrushin, N.
A1 - Hvatzkiy, K.
A1 - Gerasimov, V.
A1 - Link, T.
A1 - Epishin, A.
A1 - Nolze, Gert
A1 - Gerstein, G.
T1 - A single-crystal co-base superalloy strengthened by gamma' precipitates: structure and mechanical properties
JF - Advanced engineering materials
N2 - An experimental Co-base superalloy was designed from the Ni-base system by exchange of Ni and Co concentrations. The alloy consist of a Co-matrix (γ phase) strengthened by cuboidal precipitates Co3(Al,X) (γ' phase). The γ'-solvus temperature is 1?005?°C. [001] single crystals of this alloy were solidified and tested for tension at different temperatures up to 1?000?°C. It was found that the Co-base alloy has a much lower yield stress than a corresponding Ni-base alloy, but a much higher ductility. The partitioning behaviour of the alloying elements in the Co-base alloy and the deformation mechanisms were investigated by scanning and transmission electron microscopy.
KW - Microstructure
KW - Precipitation
KW - Stress
Y1 - 2015
U6 - http://dx.doi.org/10.1002/adem.201500088
SN - 1438-1656
VL - 17
IS - 6
SP - 755
EP - 760
PB - Wiley-VCH Verl.
CY - Weinheim
ER -
TY - JOUR
A1 - Vos, M.
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
T1 - Element-specific Kikuchi patterns of Rutile
JF - Ultramicroscopy
N2 - The kinetic energy of keV electrons backscattered from a rutile (TiO2) surface depends measurably on the mass of the scattering atom. This makes it possible to determine separately the angular distribution of electrons backscattered elastically from either Ti or O. Diffraction effects of these backscattered electrons inside the rutile crystal lead to the formation of Kikuchi patterns. The element-resolved Kikuchi patterns of Ti and O differ characteristically, but each can be described fairly well in terms of the dynamical theory of diffraction. Qualitatively, much of the differences can be understood by considering the relative arrangement of the Ti and O atoms with respect to planes defined by the crystal lattice.
KW - Electron Rutherford backscattering
KW - TiO2
KW - Kikuchi pattern
KW - EBSD pattern
KW - Simulation
Y1 - 2015
U6 - http://dx.doi.org/10.1016/j.ultramic.2015.04.018
SN - 0304-3991
VL - 156
SP - 50
EP - 58
ER -
TY - JOUR
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
T1 - Chirality determination of quartz crystals using electron backscatter diffraction
JF - Ultramicroscopy
N2 - We demonstrate the determination of crystal chirality using electron backscatter diffraction (EBSD) in the scanning electron microscope. The chirality of a-quartz as a space-group-dependent property is verified via direct comparison of experimental diffraction features to simulations using the dynamical theory of electron diffraction.
KW - Electron backscatter diffraction
KW - Kikuchi patterns
KW - Chirality
KW - Quartz
Y1 - 2015
UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:000348455100008
U6 - http://dx.doi.org/10.1016/j.ultramic.2014.11.013
SN - 0304-3991
VL - 149
SP - 58
EP - 63
PB - Elsevier
CY - New York, NY
ER -
TY - JOUR
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
T1 - Point-group sensitive orientation mapping of non-centrosymmetric crystals
JF - Applied physics letters
N2 - We demonstrate polarity-sensitive orientation mapping of non-centrosymmetric phases by Electron Backscatter Diffraction (EBSD). The method overcomes the restrictions of kinematic orientation determination by EBSD, which is limited to the centro-symmetric Laue-groups according to Friedel's rule. Using polycrystalline GaP as an example, we apply a quantitative pattern matching approach based on simulations using the dynamical theory of electron diffraction. This procedure results in a distinct assignment of the local orientation according to the non-centrosymmetric point group of the crystal structure under investigation.
KW - Scanning electron microscopy
KW - Electron backscatter diffraction
KW - Orientation mapping
KW - Non-centrosymmetric crystals
Y1 - 2015
U6 - http://dx.doi.org/10.1063/1.4907938
SN - 0003-6951
SN - 1077-3118
VL - 106
SP - 072101-1
EP - 072101-4
PB - American Institute of Physics
CY - Melville, NY
ER -