Probing Microstructure Dynamics With X-Ray Diffraction Microscopy

Suter, Robert; Hefferan, Christopher M.; Li, Shiu Fai; Hennessy, Daniel; Xiao, Chao; Lienert, U.; Tieman, Brian

doi:10.1115/1.2840965

Cited by 25 publications

(31 citation statements)

References 9 publications

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“…Developments in nondestructive materials characterization methods have been successfully employed to study microstructural evolution under thermomechanical loading conditions (17,50,(65)(66)(67)(68), thus allowing better understanding of the heterogeneous materials behavior. In particular, near-field high-energy X-ray diffraction microscopy (nf-HEDM) (69,70,71) is one of the synchrotron-based techniques that permit measurement of the spatially resolved orientations of grains that are embedded deeply in the bulk sample. This eliminates any concerns about surface relaxation effects (17, 72, 73).…”

Section: Three-dimensional Characterizationmentioning

confidence: 99%

Polycrystal Plasticity: Comparison Between Grain - Scale Observations of Deformation and Simulations

Pokharel

Lind²,

Kanjarla³

et al. 2014

Annu. Rev. Condens. Matter Phys.

144

104

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The response of polycrystals to plastic deformation is studied at the level of variations within individual grains, and comparisons are made to theoretical calculations using crystal plasticity (CP). We provide a brief overview of CP and a review of the literature, which is dominated by surface observations. The motivating question asks how well CP represents the mesoscale behavior of large populations of dislocations (as carriers of plastic strain). The literature shows consistently that only moderate agreement is found between experiment and calculation. We supplement this with a current example of microstructure evolution in the interior of a copper sample subjected to tensile deformation. Nondestructive measurements of orientation fields were performed using the near-field highenergy X-ray diffraction microscopy (nf-HEDM) technique at the Advanced Photon Source (APS). Starting at highly ordered grains, a single two-dimensional slice of microstructure containing ∼150 grains was followed through multiple strain states, where it tracked lattice rotations and defect accumulation of up to 14% elongation. In accord with the literature, at the scale of individual grains, comparison of observations with CP models indicates reasonable qualitative agreement but significant variations between simulation and experiment are apparent. The conclusion is that in order to be able to quantify the effects of microstructure on the distributions of slip, orientation change, and damage accumulation, the empirically derived constitutive relations used in continuumscale simulations need to be improved. Equally important will be the development of large-scale simulations of polycrystals that directly model dislocations. 317Annu. Rev. Condens. Matter Phys. 2014.5:317-346. Downloaded from www.annualreviews.org by University of Texas -San Antonio on 08/26/14. For personal use only.

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Section: Three-dimensional Characterizationmentioning

confidence: 99%

Polycrystal Plasticity: Comparison Between Grain - Scale Observations of Deformation and Simulations

Pokharel

Lind²,

Kanjarla³

et al. 2014

Annu. Rev. Condens. Matter Phys.

144

104

View full text Add to dashboard Cite

show abstract

“…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%

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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“…10 Methods have also been developed to reconstruct the entire 3-D grain map, layer by layer, which mimics serial sectioning but in a nondestructive mode. 14,15 The primary disadvantage of all these experimental methods is that they currently require the use of very high brightness and high energy x-ray sources, such as those produced by synchrotron particle accelerators, 8 and this requirement restricts the general availability and applicability of these methods at present.…”

Section: Michael D Uchic Michael a Groeber And Anthony D Rollettmentioning

confidence: 99%

Automated serial sectioning methods for rapid collection of 3-D microstructure data

Uchic

Groeber

Rollett

2011

JOM

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Probing Microstructure Dynamics With X-Ray Diffraction Microscopy

Cited by 25 publications

References 9 publications

Polycrystal Plasticity: Comparison Between Grain - Scale Observations of Deformation and Simulations

Polycrystal Plasticity: Comparison Between Grain - Scale Observations of Deformation and Simulations

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

Automated serial sectioning methods for rapid collection of 3-D microstructure data

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