TY - JOUR A1 - Winkelmann, Aimo A1 - Nolze, Gert T1 - Channeling-enhanced EDX for polarity resolved crystal orientation determination N2 - Using channeling-enhanced energy-dispersive X-ray spectroscopy (EDX), we demonstrate polarity sensitive orientation determination of a non-centrosymmetric crystal in the scanning electron microscope. The authors observe a characteristic asymmetry in the channeling-enhanced, angle-dependent EDX data of a GaAs sample, which is in good agreement to simulations using the dynamical theory of diffraction for the incident electron beam. This allows us to assign the orientation of the GaAs crystal according to the non-centrosymmetric point group. The method shown here overcomes the limitation of a reduced point-group sensitivity of electron backscatter diffraction Patterns and electron channeling patterns for crystalline phases that contain atoms of approximately equal electron scattering cross sections. KW - Channeling KW - EDX KW - EDS KW - Composition KW - GaAs KW - GaP PY - 2016 DO - https://doi.org/10.1002/crat.201600258 SN - 0232-1300 SN - 0023-4753 VL - 51 IS - 12 SP - 752 EP - 756 AN - OPUS4-38098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert T1 - Interphase boundary characterization in duplex steel and iron meteorites using EBSD technique N2 - The properties of materials are mainly described by the orientation distribution of the crystalline phases in a material. Beside the so considered anisotropy also the grain as well as phase boundaries are of extreme importance for a whole string of properties, e.g. the strength of a material. On the example of the interface between fcc and bcc iron the discovered and derived models are discussed. Although the common models are based on the crystal lattice description, the atomic configuration on the interface is analysed. Since experimentally a wide spread of orientations data appears the consideration of the frequency distribution is proposed to find at least the main orientation relationship between fcc and bcc. High-indexed pole figures as well as the Euler subspace are introduced in order to increase the accuracy and to compare different measurements. For the sake of simplicity EBSD measurements on iron meteorites are used since they commonly consist of large fcc single crystals which transformed to a low and very specific number of bcc grains. In special cases the described procedure could also be used for steels. KW - Orientation relationships KW - Electron backscatter diffraction KW - Steel KW - Iron meteorites KW - Kurdjumov-Sachs KW - Nishiyama-Wassermann PY - 2006 SN - 1733-3490 SN - 0004-0770 SN - 0860-7052 VL - 51 IS - 1 SP - 15 EP - 22 AN - OPUS4-38030 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Glowacka, A. A1 - Wozniak, M. J. A1 - Nolze, Gert A1 - Swiatnicki, W. A. T1 - Hydrogen induced phase transformations in austenitic-ferritic steel N2 - The hydrogen influence on the microstructure of the austenitic-ferritic Cr22-Ni5-Mo3 stainless steel was investigated. Cathodic hydrogen charging was performed electrochemically from aqueous solution of 0.1M H2SO4 with hydrogen entry promoter addition. The aim of this study was to reveal microstructural changes appearing during the hydrogen charging and particularly to clarify the occurrence of phase transformations induced by hydrogen. The specific changes in both phases of steel were observed. In the ferritic phase, strong increase of dislocation density was noticed. Longer time of hydrogen charging leaded also to the strips and twin plates formation in ferrite phase. In the austenitic phase, the generation of stacking faults, followed by the formation of α' martensite was remarked. KW - Steel KW - Hydrogen KW - Embrittlement KW - Electron backscatter diffraction KW - SEM PY - 2006 DO - https://doi.org/10.4028/www.scientific.net/SSP.112.133 SN - 1662-9779 VL - 112 SP - 133 EP - 140 AN - OPUS4-38031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Geist, V. T1 - A new method for the investigation of orientation relationships in meteoritic plessite N2 - The orientation relationship (OR) between the bcc and fcc phase in the plessite microstructure of the iron meteorites Watson, Agpalilik and Gibeon has been analysed in a scanning electron microscope using electron back-scattered diffraction (EBSD). A very strong OR exists, independently on the analysed plessite type and the observed spreading of single orientation data. The agreement between the experimental orientation distribution and existing models varies for each meteorite. The black plessite in the Agpalilik corresponds to the Nishiyama-Wassermann model whereas the Duplex plessite of the Gibeon meteorite shows an OR close to the Kurdjumov-Sachs model. The Watson meteorite is strongly deformed so that a general OR is difficult to determine due to the blurred experimental orientation distribution. KW - Meteorite KW - Orientation relationship KW - Steel KW - Electron backscatter diffraction KW - Kurdjumov-Sachs KW - Nishiyama-Wassermann PY - 2004 DO - https://doi.org/10.1002/crat.200310193 SN - 0023-4753 SN - 0232-1300 VL - 39 IS - 4 SP - 343 EP - 352 AN - OPUS4-38032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, Werner A1 - Nolze, Gert T1 - POWDER CELL-A Program for the representation and manipulation of crystal structure and calculation of the resulting X-ray powder pattern N2 - The main component of this program is a simultaneous representation of the unit cell and the calculated powder pattern. It allows the manipulation of the Crystal structure by moving selected atoms of the asymmetric unit. The resulting powder pattern can be directly compared to experimental data in order to obtain reliable starting values for further computations in refinement programs. KW - XRD KW - Simulation KW - PowderCell KW - Programming KW - Crystal structure KW - Refinement PY - 1996 SN - 0021-8898 VL - 29 SP - 301 EP - 303 AN - OPUS4-38033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nolze, Gert ED - Sen Gupta, S. P. ED - Chatterjee, P. T1 - PowderCell : a mixture between crystal structure visualizer, simulation and refinement tool N2 - The program PowderCell is a crystallographic tool for visualization of Crystal structures. However, it offers also non-conventional features like the fulautomatical generation of subgroups or the consideration of non-standard settings of space-group types. On the one Hand the program is very useful for non-crystallographers who like to get an impression of the atomic arrangement within the unit cell. But also for crystallographers it is recommendable because it contains a lot of additional information which can be extracted and used like data given in the International Tables for Crystallography, Vol. A. However, the most important advantage of the program is the simultaneous calculation of the X-ray or neutron diffraction powder patterns for a mixture of up to 10 crystalline phases. Between more than 7 different characteristic radiations can be chosen and their influence on the resulting powder pattern can be studied. Furthermore, experimental diffractograms can be analysed using a refinement procedure. The implemented LeBail-algorithm allows the investigation of unknown phases. In combination with the refinement algorithm an interface to Shelx offers the possibility for a step by step ab initio structure analysis. Certainly, the user-friendly shell is one reason that especially users who are not so familar with space-group symmetry, crystal structure data or diffractometry use this powerful tool for the solution of scientific or analytical problems as well as in teaching. KW - XRD KW - Simulation KW - Crystal structure KW - Neutron diffraction PY - 2002 SN - 8177642626 SN - 9788177642629 SP - 146 EP - 155 PB - Allied Publishers CY - Kolkata, India AN - OPUS4-38035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nolze, Gert ED - Sen Gupta, S. P. ED - Chatterjee, P. T1 - The determination of residual stress N2 - X-ray stress analysis on crystalline materials is based on the determination of elastic lattice strains. The strains described by the shift of peak positions are converted to stresses by the means of theory of elasticity. The development of the sin2ψ-method of X-ray stress analysis introduced an enormous progress in X-ray stress analysis during the last decades. This report outlines some important elements of X-ray physics and fundamentals of theory of elasticity. The Standard measuring procedure are described and special experimental differences to the common powder diffractometry are outlined. KW - XRD KW - Residual stress PY - 2002 SN - 81-7764-262-6 SN - 9788177642629 SP - 77 EP - 83 PB - Allied Publishers CY - Kolkata, India AN - OPUS4-38036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Kraus, Werner T1 - PowderCell 2.0 for Windows N2 - PowderCell contains a comfortable, user friendly visualization and modification tool for crystal structures. It provides on-line calculation of the corresponding powder diffraction patterns simulating a variety of experimental conditions. The common ICSD and Shelx file formats are supported for importing crystal structure information. It has control of automatic cell transformation and also derivation of subgroups. More than 740 different settings of the 230 space-group types are supported. Up to ten crystal structures can be considered simultaneously. A full pattern refinement enables the direct comparison with experimental diffractograms for quantitative phase analysis, lattice parameter refinement, polynomial background estimation, etc. KW - XRD KW - Simulation KW - Powdercell KW - Software KW - Programming KW - Phase mixtures KW - Crystal structure KW - Subgroup PY - 1998 SN - 0885-7156 VL - 13 IS - 4 SP - 256 EP - 259 PB - Cambridge University Press AN - OPUS4-38037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lühr, T. A1 - Winkelmann, Aimo A1 - Nolze, Gert A1 - Krull, D. A1 - Westphal, C. T1 - Direct Atom Imaging by Chemical-Sensitive Holography N2 - In order to understand the physical and chemical properties of advanced materials, functional molecular adsorbates, and protein structures, a detailed knowledge of the atomic arrangement is essential. Up to now, if subsurface structures are under investigation, only indirect methods revealed reliable results of the atoms’ spatial arrangement. An alternative and direct method is three-dimensional imaging by means of holography. Holography was in fact proposed for electron waves, because of the electrons’ short wavelength at easily accessible energies. Further, electron waves are ideal structure probes on an atomic length scale, because electrons have a high scattering probability even for light elements. However, holographic reconstructions of electron diffraction patterns have in the past contained severe image artifacts and were limited to at most a few tens of atoms. Here, we present a general reconstruction algorithm that leads to high-quality atomic images showing thousands of atoms. Additionally, we show that different elements can be identified by electron holography for the example of FeS₂ . KW - holography KW - electron diffraction KW - atomic imaging KW - photoemission KW - electron backscattering PY - 2016 DO - https://doi.org/10.1021/acs.nanolett.6b00524 VL - 16 IS - 5 SP - 3195 EP - 3201 PB - American Chemical Society AN - OPUS4-37739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dietrich, D. A1 - Nolze, Gert A1 - Mehner, T. A1 - Nickel, D. A1 - Lampke, T. T1 - EDS/EBSD studies and HR-EBSD pattern analysis on pre-Inca ceramic fragments recovered during San José de Moro Archaeology Program N2 - Pre-Inca civilizations like the coastal cultures Moche and Nazca (Early Intermediate) and the inland culture Wari (Middle Horizon) were agrarian societies which supported indigenous elites of impressive wealth, power, and organization. With the expansion of the Wari Empire, the polychrome style and technique of Nazca propagated to the other cultures. High status burials, most of the Late Moche Fine Line ceramics and a large corpus of ceramics with Wari-derived decoration have been recovered in San José de Moro since 1991. The degree of transfer of procedures in this highly interactive scenario is of special interest: is there a limitation to decoration or is it adopted by the local potters also regarding the formulation of the ceramic bodies? In this context the relative amount, size and type of incorporated non-plastic inclusions as temper are important. T2 - The 16th European Microscopy Congress 2016 CY - Lyon, France DA - 28.08.2016 KW - EBSD KW - EDX KW - Ceramic KW - Phase distribution KW - Microstructure KW - Texture KW - Phase identification KW - SEM PY - 2016 DO - https://doi.org/10.1002/9783527808465.EMC2016.4462 SP - 4462 PB - John Wiley & Sons AN - OPUS4-37740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Hielscher, R. ED - Hielscher, Ralf T1 - Orientations - perfectly colored N2 - The inverse pole figure (IPF) coloring for a suitable evaluation of crystal orientation data is discussed. The major goal is a high correlation between encoding color and crystal orientation. Revised color distributions of the fundamental sectors are introduced which have the advantages of (1) being applicable for all point groups, (2) not causing color discontinuities within grains, (3) featuring carefully balanced regions for red, cyan, blue, magenta, green and yellow, and (4) an enlarged gray center in opposition to a tiny white center. A new set of IPF color keys is proposed which is the result of a thorough analysis of the colorization problem. The discussion considers several topics: (a) the majority of presently applied IPF color keys generate color discontinuities for specifically oriented grains; (b) if a unique correlation between crystal direction and color is requested, discontinuity-preventing keys are possible for all point groups, except for 4, 3 and 1; (c) for a specific symmetry group several IPF color keys are available, visualizing different features of a microstructure; and (d) for higher symmetries a simultaneous IPF mapping of two or three standard reference directions is insufficient for an unequivocal orientation assignment. All color keys are available in MTEX, a freely available MATLAB toolbox. KW - Electron backscatter diffraction KW - Color coding KW - Symmetry groups KW - Orientation description PY - 2016 DO - https://doi.org/10.1107/S1600576716012942 SN - 0021-8898 SN - 1600-5767 VL - 49 IS - 5 SP - 1786 EP - 1802 AN - OPUS4-37741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -