Multigrain crystallography

Sørensen, Henning Osholm; Schmidt, Søren; Wright, Jonathan P.; Vaughan, Gavin; Techert, Simone; Garman, Elspeth F.; Oddershede, Jette; Davaasambuu, Jav; Paithankar, Karthik S.; Gundlach, Carsten; Poulsen, Henning Friis

doi:10.1524/zkri.2012.1438

Cited by 106 publications

(89 citation statements)

References 61 publications

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“…For voxels with more than one plausible grain assignment, the orientation is chosen that results in the most complete diffraction pattern. Here, completeness is defined as the number of diffraction spots observed at spatially correct locations on the near-field detector divided by the expected number of diffraction spots when the voxel in question is assigned to a particular lattice orientation (19). Near the center of a grain, we typically obtain completeness values close to 100%, but this value falls off sharply in the vicinity of grain boundaries.…”

Section: Methodsmentioning

confidence: 99%

“…With the advent of diffraction-based imaging techniques, such as 3D X-ray diffraction (3DXRD) microscopy (18,19), high-energy diffraction microscopy (20), and diffraction-contrast tomography (21), it is now feasible to perform nondestructive, 3D mapping of the shapes and lattice orientations of thousands of crystallites within a polycrystalline specimen. From a sequence of such measurements applied to the same sample, we can track its microstructural evolution and determine whether a particular processing protocol [such as a heat treatment (22)(23)(24) or a mechanical deformation (25)(26)(27)] induced grain rotation.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Direct observation of grain rotations during coarsening of a semisolid Al–Cu alloy

Dake

Oddershede

Sørensen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Sintering is a key technology for processing ceramic and metallic powders into solid objects of complex geometry, particularly in the burgeoning field of energy storage materials. The modeling of sintering processes, however, has not kept pace with applications. Conventional models, which assume ideal arrangements of constituent powders while ignoring their underlying crystallinity, achieve at best a qualitative description of the rearrangement, densification, and coarsening of powder compacts during thermal processing. Treating a semisolid Al-Cu alloy as a model system for late-stage sintering-during which densification plays a subordinate role to coarsening-we have used 3D X-ray diffraction microscopy to track the changes in sample microstructure induced by annealing. The results establish the occurrence of significant particle rotations, driven in part by the dependence of boundary energy on crystallographic misorientation. Evidently, a comprehensive model for sintering must incorporate crystallographic parameters into the thermodynamic driving forces governing microstructural evolution.3D microstructural evolution | sintering | Ostwald ripening | grain rotation | x-ray imaging W hether we realize it or not, our daily lives are marked by encounters with sintering, ranging from natural rock formations and glaciers to artificial products like the porcelain from which we eat or the amalgam fillings in many teeth. Sintering is an efficient method for combining loose granular precursors into solid objects of predetermined shape at relatively low temperature, circumventing the processing route of melting, casting, and machining. The applications of sintering are widespread. For example, it is the predominant method for producing bulk technical ceramics (1), and, thanks to advances in powder metallurgy, sintering is of growing importance in the fabrication of metals, as well (2). The focus in recent years on nanostructured materials-specifically, on materials for energy storage and conversion-has intensified the scientific investigation and modeling of sintering processes. The latter find application in the production of fuel cells (3) and battery electrodes (4). In other applications, such as catalysis (5), sintering can be highly undesirable, as it reduces the connectivity of pores and the free surface of nanoparticles. In all of these cases, we need a firm understanding of sintering fundamentals to achieve and retain desired materials properties during thermal processing.The reduction in free energy that accompanies the removal of a powder compact's surface area is the driving force behind sintering (2, 6). When two particles come into contact, two free surfaces are replaced by a single solid/solid boundary. If the particles are crystalline, the new interface is a grain boundary, the (excess) energy of which is generally on the order of one-third of that of a (single) free surface of equal area (6); consequently, the sintering process results in a net release of energy. As free surface area decreases, the powder ...

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Section: Methodsmentioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Direct observation of grain rotations during coarsening of a semisolid Al–Cu alloy

Dake

Oddershede

Sørensen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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show abstract

“…This method is ideal for laser-heated samples that often result in multiple small singlecrystal grains that then give spotty diffraction patterns. For a quenched sample at 110 GPa, we searched the ω range of −20°to +20°and at least 21 single crystals were identified by the MGC software (22). The statistics of all grains and crystallographic data for five selected grains are listed in Tables S1-S6.…”

Section: Significancementioning

confidence: 99%

Dehydrogenation of goethite in Earth’s deep lower mantle

Kim

Liu

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The cycling of hydrogen influences the structure, composition, and stratification of Earth's interior. Our recent discovery of pyrite-structured iron peroxide (designated as the P phase) and the formation of the P phase from dehydrogenation of goethite FeO 2 H implies the separation of the oxygen and hydrogen cycles in the deep lower mantle beneath 1,800 km. Here we further characterize the residual hydrogen, x, in the P-phase FeO 2 Hx. Using a combination of theoretical simulations and high-pressure-temperature experiments, we calibrated the x dependence of molar volume of the P phase. Within the current range of experimental conditions, we observed a compositional range of P phase of 0.39 < x < 0.81, corresponding to 19-61% dehydrogenation. Increasing temperature and heating time will help release hydrogen and lower x, suggesting that dehydrogenation could be approaching completion at the high-temperature conditions of the lower mantle over extended geological time. Our observations indicate a fundamental change in the mode of hydrogen release from dehydration in the upper mantle to dehydrogenation in the deep lower mantle, thus differentiating the deep hydrogen and hydrous cycles.

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“…An algorithm called Grainspotter (Schmidt, 2014), part of the Fable software platform (Fable, 2003), utilizes the properties of Rodrigues-Frank (RF) space to index wedge datasets for polycrystalline inorganic materials structure determination (Sørensen et al, 2012). It has been used to index insulin and hen egg white lysozyme datasets collected at a synchrotron radiation facility with multiple crystals in the beam (Paithankar et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

FELIX: an algorithm for indexing multiple crystallites in X-ray free-electron laser snapshot diffraction images

et al. 2017

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A novel algorithm for indexing multiple crystals in snapshot X-ray diffraction images, especially suited for serial crystallography data, is presented. The algorithm, FELIX, utilizes a generalized parametrization of the RodriguesFrank space, in which all crystal systems can be represented without singularities. The new algorithm is shown to be capable of indexing more than ten crystals per image in simulations of cubic, tetragonal and monoclinic crystal diffraction patterns. It is also used to index an experimental serial crystallography dataset from lysozyme microcrystals. The increased number of indexed crystals is shown to result in a better signal-to-noise ratio, and fewer images are needed to achieve the same data quality as when indexing one crystal per image. The relative orientations between the multiple crystals indexed in an image show a slight tendency of the lysozme microcrystals to adhere on (110) facets.

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Multigrain crystallography

Cited by 106 publications

References 61 publications

Direct observation of grain rotations during coarsening of a semisolid Al–Cu alloy

Direct observation of grain rotations during coarsening of a semisolid Al–Cu alloy

Dehydrogenation of goethite in Earth’s deep lower mantle

FELIX: an algorithm for indexing multiple crystallites in X-ray free-electron laser snapshot diffraction images

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