Loading dependence and tension–compression asymmetry of deformation twinning in textured Mg-3Al-1Zn alloy: A multiscale synchrotron X-ray study

Three-dimensional X-ray orientation microscopy based on X-ray full-field imaging techniques such as diffraction contrast tomography is a challenging task when it comes to materials displaying non-negligible intragranular orientation spread and/or intricate grain microstructures as a result of plastic deformation and deformation twinning. As shown in this article, the optimization of the experimental conditions and a number of modifications of the data analysis routines enable detection and three-dimensional reconstruction of twin lamellae down to micrometre thickness, as well as more accurate three-dimensional reconstruction of grains displaying intragranular orientation spreads of up to a few degrees. The reconstruction of spatially resolved orientation maps becomes possible through the use of a recently introduced six-dimensional reconstruction framework, which has been further extended in order to enable simultaneous reconstruction of parent and twin orientations and to account for the finite impulse response of the X-ray imaging detector. The simultaneous reconstruction of disjoint orientation domains requires appropriate scaling of the scattering intensities based on structure and Lorentz factors and yields three-dimensional reconstructions with comparable density values for all the grains. This in turn enables the use of a global intensity-guided assembly procedure and avoids problems related to the single-grain thresholding procedure used previously. Last but not least, carrying out a systematic search over the list of known twin variants (forward modelling) for each of the indexed parent grains, it is possible to identify additional twins which have been left undetected at the previous stage of grain indexing based on diffraction spot peak positions. The enhanced procedure has been tested on a 1% deformed specimen made from a Ti–4% Al alloy and the result has been cross-validated against a two-dimensional electron backscatter diffraction orientation map acquired on one of the lateral sample surfaces.

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Deformation twinning and residual stress in calcite studied with synchrotron polychromatic X-ray microdiffraction

Physics and Chemistry of Minerals ◽

10.1007/s00269-011-0422-7 ◽

2011 ◽

Vol 38 (6) ◽

pp. 491-500 ◽

Cited By ~ 14

Author(s):

Kai Chen ◽

Martin Kunz ◽

Nobumichi Tamura ◽

Hans-Rudolf Wenk

Keyword(s):

Residual Stress ◽

Deformation Twinning ◽

X Ray

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On the deformation twinning of Mg AZ31B: A three-dimensional synchrotron X-ray diffraction experiment and crystal plasticity finite element model

International Journal of Plasticity ◽

10.1016/j.ijplas.2015.03.001 ◽

2015 ◽

Vol 70 ◽

pp. 77-97 ◽

Cited By ~ 75

Author(s):

Hamidreza Abdolvand ◽

Marta Majkut ◽

Jette Oddershede ◽

Søren Schmidt ◽

Ulrich Lienert ◽

...

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Crystal Plasticity ◽

Three Dimensional ◽

Element Model ◽

Deformation Twinning ◽

Diffraction Experiment ◽

X Ray Diffraction ◽

X Ray ◽

Crystal Plasticity Finite Element

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Capture Deformation Twinning in Mg during Shock Compression with Ultrafast Synchrotron X-Ray Diffraction

Physical Review Letters ◽

10.1103/physrevlett.123.255501 ◽

2019 ◽

Vol 123 (25) ◽

Cited By ~ 3

Author(s):

S. Chen ◽

Y. X. Li ◽

N. B. Zhang ◽

J. W. Huang ◽

H. M. Hou ◽

...

Keyword(s):

Shock Compression ◽

Deformation Twinning ◽

X Ray Diffraction ◽

X Ray

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Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

International Astronomical Union Colloquium ◽

10.1017/s0252921100025446 ◽

1994 ◽

Vol 144 ◽

pp. 275-277

Author(s):

M. Karlický ◽

J. C. Hénoux

Keyword(s):

Time Distribution ◽

Electron Bombardment ◽

Spatial Evolution ◽

Superthermal Electrons ◽

Flare Loop ◽

X Ray ◽

Superthermal Electron ◽

Flare Loops ◽

Chromospheric Evaporation ◽

Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

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Some Problems in Understanding the Solar Corona

International Astronomical Union Colloquium ◽

10.1017/s025292110002491x ◽

1994 ◽

Vol 144 ◽

pp. 1-9

Author(s):

A. H. Gabriel

Keyword(s):

Solar Corona ◽

Solar Atmosphere ◽

Theoretical Modelling ◽

Total System ◽

Major Advance ◽

X Ray ◽

Proper Perspective ◽

Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

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White-Light Coronal Structures: Streamers and CMEs

International Astronomical Union Colloquium ◽

10.1017/s0252921100025045 ◽

1994 ◽

Vol 144 ◽

pp. 82

Author(s):

E. Hildner

Keyword(s):

Emission Line ◽

Electron Density ◽

White Light ◽

Coronal Mass Ejections ◽

X Rays ◽

Solar Cycles ◽

Temperature Function ◽

X Ray ◽

Eclipse Observations ◽

Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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