scholarly journals Formation and annihilation of stressed deformation twins in magnesium

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Karim Louca ◽  
Hamidreza Abdolvand ◽  
Charles Mareau ◽  
Marta Majkut ◽  
Jonathan Wright
Keyword(s):  
Mechanical Response ◽  
Axial Stress ◽  
Three Dimensional ◽  
Service Performance ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
Sign Reversal ◽  
X Ray ◽  
Hexagonal Close Packed

AbstractThe mechanical response of polycrystalline materials to an externally applied load and their in-service performance depend on the local load partitioning among the constituent crystals. In hexagonal close-packed polycrystals such load partitioning is significantly affected by deformation twinning. Here we report in-situ compression-tension experiments conducted on magnesium specimens to measure the evolution of grain resolved tensorial stresses and formation and annihilation of twins. More than 13000 grains and 1300 twin-parent pairs are studied individually using three-dimensional synchrotron X-ray diffraction. It is shown that at the early stages of plasticity, the axial stress in twins is higher than that of parents, yet twins relax with further loading. While a sign reversal is observed for the resolved shear stress (RSS) acting on the twin habit plane in the parent, the sign of RSS within the majority of twins stays unchanged until twin annihilation during the load reversal. The variations of measured average stresses across parents and twins are also investigated.

scholarly journals In Situ Coherent X-ray Diffraction during Three-Point Bending of a Au Nanowire: Visualization and Quantification

2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Anton Davydok ◽  
Thomas Cornelius ◽  
Zhe Ren ◽  
Cedric Leclere ◽  
Gilbert Chahine ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Complex Deformation ◽  
X Ray ◽  
Three Point Bending ◽  
Atomic Force ◽  
Au Nanowire ◽  
Before And After

The three-point bending behavior of a single Au nanowire deformed by an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. Three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves and were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire was visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion was detected. Bending and torsion angles were quantified from the high-resolution diffraction data.

Three dimensional V2O5/NaV6O15 hierarchical heterostructures: Controlled synthesis and synergistic effect investigated by in situ X-ray diffraction

Nano Energy ◽  
2016 ◽  
Vol 27 ◽  
pp. 147-156 ◽  
Author(s):  
Chaojiang Niu ◽  
Xiong Liu ◽  
Jiashen Meng ◽  
Lin Xu ◽  
Mengyu Yan ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Three Dimensional ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals X-Ray Single Crystal Structural Analysis of Magnetically Oriented Microcrystals

2014 ◽  
Vol 70 (a1) ◽  
pp. C1138-C1138
Author(s):  
Chiaki Tsuboi ◽  
Kazuki Aburaya ◽  
Shingo Higuchi ◽  
Fumiko Kimura ◽  
Masataka Maeyama ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Three Dimensional ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Data Set ◽  
Uv Curable ◽  
X Ray

We have developed magnetically oriented microcrystal array (MOMA) technique that enables single crystal X-ray diffraction analyses from microcrystalline powder. In this method, microcrystals suspended in a UV-curable monomer matrix are there-dimensionally aligned by special rotating magnetic field, followed by consolidation of the matrix by photopolymerization. From thus achieved MOMAs, we have been succeeded in crystal structure analysis for some substances [1, 2]. Though MOMA method is an effective technique, it has some problems as follows: in a MOMA, the alignment is deteriorated during the consolidation process. In addition, the sample microcrystals cannot be recovered from a MOMA. To overcome these problems, we performed an in-situ X-ray diffraction measurement using a three-dimensional magnetically oriented microcrystal suspension (3D MOMS) of L-alanine. An experimental setting of the in-situ X-ray measurement of MOMS is schematically shown in the figure. L-alanine microcrystal suspension was poured into a glass capillary and placed on the rotating unit equipped with a pair of neodymium magnets. Rotating X-ray chopper with 10°-slits was placed between the collimator and the suspension. By using this chopper, it was possible to expose the X-ray only when the rotating MOMS makes a specific direction with respect to the impinging X-ray. This has the same effect as the omega oscillation in conventional single crystal measurement. A total of 22 XRD images of 10° increments from 0° to 220° were obtained. The data set was processed by using conventional software to obtain three-dimensional molecular structure of L-alanine. The structure is in good agreement with that reported for the single crystal. R1 and wR2 were 6.53 and 17.4 %, respectively. RMSD value between the determined molecular structure and the reported one was 0.0045 Å. From this result, we conclude that this method can be effective and practical to be used widely for crystal structure analyses.

Crystal plasticity in shock-compressed hcp-iron

2021 ◽  
Author(s):  
Sébastien Merkel ◽  
Sovanndara Hok ◽  
Cynthia Bolme ◽  
Wendy Mao ◽  
Arianna Gleason
Keyword(s):  
Free Electron ◽  
Deformation Mechanisms ◽  
Free Electron Lasers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Planetary Cores ◽  
Materials Behavior ◽  
Optical Laser

<p>Iron is a key constituent of planetary core and an important technological material. Here, we combine <em>in situ</em> ultrafast X-ray diffraction at free electron lasers with optical-laser-induced shock compression experiments on polycrystalline Fe to study the plasticity of hexagonal close-packed (hcp)-Fe under extreme loading states. We identifiy the deformation mechanisms that controls the Fe microstructures and  observe a significant time-evolution of stress over the few nanoseconds of the experiments. These observations illustrate how ultrafast plasticity studies can reveal distinctive materials behavior under extreme loading states and will help constraining the pressure, temperature, and strain rate dependence of materials behavior in planetary cores.</p>

In situ coupling of atomic force microscopy and sub-micrometer focused X-ray techniques

2014 ◽  
Vol 1712 ◽  
Author(s):  
Thomas W. Cornelius ◽  
Zhe Ren ◽  
Francesca Mastropietro ◽  
Simon Langlais ◽  
Anton Davydok ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Elemental Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Nanowires ◽  
Force Microscopy ◽  
Indentation Tests ◽  
Scanning Force ◽  
Diffraction Patterns

ABSTRACTA scanning force microscope for in situ nanofocused X-ray studies (SFINX) has been developed which can be installed on diffractometers at synchrotron beamlines allowing for the combination with various techniques such as coherent X-ray diffraction and fluorescence. The capabilities of this device are demonstrated on Cu nanowires and on Au islands grown on sapphire (0001). The sample topography, crystallinity, and elemental distribution of the same area are investigated by recording simultaneously an AFM image, a scanning X-ray diffraction map, and a fluorescence map. Additionally, the mechanical response of Au islands is studied by in situ indentation tests employing the AFM-tip and recording 2D X-ray diffraction patterns during mechanical loading.

Observation of non-basal slip in Mg-Y by in situ three-dimensional X-ray diffraction

2018 ◽  
Vol 143 ◽  
pp. 44-48 ◽  
Author(s):  
Zhonghe Huang ◽  
Leyun Wang ◽  
Bijin Zhou ◽  
Torben Fischer ◽  
Sangbong Yi ◽  
...  
Keyword(s):  
Basal Slip ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray

High Resolution Synchrotron X-Ray Diffraction Tomography Of Large-Grained Samples

1996 ◽  
Vol 437 ◽  
Author(s):  
D.P. Piotrowski ◽  
S.R. Stock ◽  
A. Guvenilir ◽  
J.D. Haase ◽  
Z.U. Rek
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Three Dimensional ◽  
Polycrystalline Materials ◽  
Diffraction Tomography ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Image Storage ◽  
X Ray ◽  
Dimensional Distribution

AbstractIn order to understand the macroscopic response of polycrystalline structural materials to loading, it is frequently essential to know the spatial distribution of strain as well as the variation of micro-texture on the scale of 100 μm. The methods must be nondestructive, however, if the three-dimensional evolution of strain is to be studied. This paper describes an approach to high resolution synchrotron x-ray diffraction tomography of polycrystalline materials. Results from model samples of randomly-packed, millimeter-sized pieces of Si wafers and of similarly sized single-crystal Al blocks have been obtained which indicate that polychromatic beams collimated to 30 μm diameter can be used to determine the depth of diffracting volume elements within ± 70 μm. The variation in the two-dimensional distribution of diffracted intensity with changing sample to detector separation is recorded on image storage plates and used to infer the depth of diffracting volume elements.

In Situ Three-Dimensional Orientation Mapping in Plastically-Deformed Polycrystalline Iron by Three-Dimensional X-Ray Diffraction

2014 ◽  
Vol 777 ◽  
pp. 118-123 ◽  
Author(s):  
Yujiro Hayashi ◽  
Yoshiharu Hirose ◽  
Daigo Setoyama
Keyword(s):  
Three Dimensional ◽  
Diffraction Method ◽  
Inverse Pole Figure ◽  
Coarse Grained ◽  
Uniaxial Tensile ◽  
X Ray Diffraction ◽  
Polycrystalline Iron ◽  
X Ray ◽  
Orientation Mapping

In situ three-dimensional crystallographic orientation mapping in plastically-deformed polycrystalline iron is demonstrated using a modified three-dimensional x-ray diffraction method. This voxel-by-voxel measurement method enables the observation of intragranular orientation distribution. The experiment is performed using coarse-grained ferrite with a mean grain size of ~ 60 μm and an incident x-ray beam with a beam size of 20 μm × 20 μm. Grains averagely rotate approximately toward the <110> preferred orientation of body-centered cubic uniaxial tensile texture. Intragranular orientation distributions are spread as the tensile strain increases to 10.7 %. Furthermore, intragranular multidirectional rotations are observed in grains near the <100> and <111> corners in the inverse pole figure.

scholarly journals Maximum a posteriori estimation of crystallographic phases in X-ray diffraction tomography

2015 ◽  
Vol 373 (2043) ◽  
pp. 20140392 ◽  
Author(s):  
Doĝa Gürsoy ◽  
Tekin Biçer ◽  
Jonathan D. Almer ◽  
Raj Kettimuthu ◽  
Stuart R. Stock ◽  
...  
Keyword(s):  
National Laboratory ◽  
Spinous Process ◽  
Argonne National Laboratory ◽  
Three Dimensional ◽  
Polycrystalline Materials ◽  
Reconstruction Method ◽  
Diffraction Tomography ◽  
A Posteriori ◽  
X Ray Diffraction ◽  
X Ray

A maximum a posteriori approach is proposed for X-ray diffraction tomography for reconstructing three-dimensional spatial distribution of crystallographic phases and orientations of polycrystalline materials. The approach maximizes the a posteriori density which includes a Poisson log-likelihood and an a priori term that reinforces expected solution properties such as smoothness or local continuity. The reconstruction method is validated with experimental data acquired from a section of the spinous process of a porcine vertebra collected at the 1-ID-C beamline of the Advanced Photon Source, at Argonne National Laboratory. The reconstruction results show significant improvement in the reduction of aliasing and streaking artefacts, and improved robustness to noise and undersampling compared to conventional analytical inversion approaches. The approach has the potential to reduce data acquisition times, and significantly improve beamtime efficiency.

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