VULCAN—The engineering diffractometer at the SNS

Wang, Xun-Li; Holden, T. M.; Rennich, George Q; Stoica, A. D.; Liaw, Peter K.; Choo, Hahn; Hubbard, Camden R.

doi:10.1016/j.physb.2006.06.103

Cited by 121 publications

(64 citation statements)

References 6 publications

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“…In situ neutron diffraction characterization of the 14YWT NFA under uniaxial tensile loading at room temperature (RT), 400, 600, 750 and 800°C, respectively, was performed on VULCAN 19 , the Engineering Materials Diffractometer at the SNS (see Methods, Supplementary Figs 1-4 and Supplementary Note 1 for more details of the experimental setup). The observed true stress-true strain curve at each temperature is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Stoica

Miller

et al. 2014

Nat Commun

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Nanostructured ferritic alloys are a new class of ultrafine-grained oxide dispersionstrengthened steels that have promising properties for service in extreme environments in future nuclear reactors. This is due to the remarkable stability of their complex microstructures containing numerous Y-Ti-O nanoclusters within grains and along grain boundaries. Although nanoclusters account primarily for the exceptional resistance to irradiation damage and high-temperature creep, little is known about the mechanical roles of the polycrystalline grains that constitute the ferritic matrix. Here we report an in situ mesoscale characterization of anisotropic responses of ultrafine ferrite grains to stresses using state-ofthe-art neutron diffraction. We show the experimental determination of single-crystal elastic constants for a 14YWT alloy, and reveal a strong temperature-dependent elastic anisotropy that leads to elastic softening and instability of the ferrite. We also demonstrate, from anisotropy-induced intergranular strains, that a deformation crossover exists from lowtemperature lattice hardening to high-temperature lattice softening in response to extensive plastic deformation.

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Section: Resultsmentioning

confidence: 99%

“…In situ neutron diffraction experiments were performed on VULCAN 19 , the Engineering Materials Diffractometer at the SNS, Oak Ridge National Laboratory. Threaded dogbone-shaped NFA specimens of 2.90 mm in diameter and 20.6 mm in gauge-length were uniaxially deformed under tension using a Materials Testing System load-frame.…”

Section: Methodsmentioning

confidence: 99%

Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Stoica

Miller

et al. 2014

Nat Commun

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“…34,35,36 Diffraction measurements were taken parallel to Table 1. The atomic positions and amplitudes of the modulation function of the commensurate modulated phase are listed in Table 2.…”

Section: Diffraction Measurementsmentioning

confidence: 99%

Structural modulations and magnetic properties of off-stoichiometric Ni-Mn-Ga magnetic shape memory alloys

Pramanick

Wang

et al. 2012

Phys. Rev. B

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“…Two analytical methods that we have recently implemented (such as theoretical Bragg-edge modeling and phenomenological function, which will be described in detail in the following sections) were used and the derived parameters compared with each other. Moreover, neutron diffraction measurements at SNS's VULCAN engineering materials diffractometer [34] were conducted to validate the results obtained from both approaches.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Crystallographic Structures Using Bragg-Edge Neutron Imaging at the Spallation Neutron Source

et al. 2017

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Over the past decade, wavelength-dependent neutron radiography, also known as Bragg-edge imaging, has been employed as a non-destructive bulk characterization method due to its sensitivity to coherent elastic neutron scattering that is associated with crystalline structures. Several analysis approaches have been developed to quantitatively determine crystalline orientation, lattice strain, and phase distribution. In this study, we report a systematic investigation of the crystal structures of metallic materials (such as selected textureless powder samples and additively manufactured (AM) Inconel 718 samples), using Bragg-edge imaging at the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS). Firstly, we have implemented a phenomenological Gaussian-based fitting in a Python-based computer called iBeatles. Secondly, we have developed a model-based approach to analyze Bragg-edge transmission spectra, which allows quantitative determination of the crystallographic attributes. Moreover, neutron diffraction measurements were carried out to validate the Bragg-edge analytical methods. These results demonstrate that the microstructural complexity (in this case, texture) plays a key role in determining the crystallographic parameters (lattice constant or interplanar spacing), which implies that the Bragg-edge image analysis methods must be carefully selected based on the material structures.

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VULCAN—The engineering diffractometer at the SNS

Cited by 121 publications

References 6 publications

Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Temperature-dependent elastic anisotropy and mesoscale deformation in a nanostructured ferritic alloy

Structural modulations and magnetic properties of off-stoichiometric Ni-Mn-Ga magnetic shape memory alloys

Characterization of Crystallographic Structures Using Bragg-Edge Neutron Imaging at the Spallation Neutron Source

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