A double-crystal monochromator for neutron stress diffractometry

Em, V. T.; Балагуров, А. М.; Глазков, В. П.; Karpov, I. D.; Mikula, P.; Miron, N.F.; Соменков, В. А.; Sumin, V. V.; Šaroun, Jan; Shushunov, M. N.

doi:10.1134/s0020441217040042

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…The stress distribution was studied on a STRESS neutron diffractometer on an IR-8 reactor in the National Research Center "Kurchatov Institute" [19][20][21]. To decrease the time of measurements of a neutron beam and obtain the information on the distribution of stresses over the volume of a prism, the measurements were performed by the following scheme.…”

Section: Measurement Of Stresses By the Neutron Diffraction Methodsmentioning

confidence: 99%

A Neutron Diffraction Study of the Effect Produced by the Direction of Crystal Growth on the Distribution of Residual Stresses in Austenite Steel Prisms Manufactured by Selective Laser Melting

Karpov

Rylov

et al. 2022

Phys. Metals Metallogr.

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The effect affected by the choice of the direction of the crystal growth by selective laser melting on the distribution of residual stresses was studied on the example of initiated growing of a 20 × 20 × 70-mm prism of steel 316L. Prisms with different growth directions (along their long and short edges) have been investigated. Neutron stress diffractometry providing the measurement of all three stress tensor components in massive materials and products by a nondestructive method was used. Compressive stresses are formed in the central part of a prism in both cases. They are close to zero or transit to tensile stresses when approaching the surface. In the prism grown vertically along the long edge, tensile stresses are higher and occupy a larger volume as compared to the prism grown along the short edge. Maximum tensile stresses (~500 MPa) near the vertical prism edges are close to the ultimate yield strength of the material (~540 MPa). The maximum compressive stresses (~–400 MPa) are formed in the central part of the vertical prism.

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Section: Measurement Of Stresses By the Neutron Diffraction Methodsmentioning

confidence: 99%

A Neutron Diffraction Study of the Effect Produced by the Direction of Crystal Growth on the Distribution of Residual Stresses in Austenite Steel Prisms Manufactured by Selective Laser Melting

Karpov

Rylov

et al. 2022

Phys. Metals Metallogr.

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“…Neutron diffraction measurements were carried out on the STRESS diffractometer at the IR-8 research reactor of the Kurchatov Institute in Moscow (Russia). A double monochromator made of pyrolytic graphite (PG002) and a focusing silicon crystal (Si220) [ 50 , 51 ], which outputs a monochromatic neutron beam with a wavelength λ = 1.548 Å, is used. The diffraction peak α-Ti(103) of titanium at a scattering angle of 2θ ≈ 71.40° was used in the present study, as in lamellar Ti-6Al-4V, the α phase accounts for around 90% of the crystallographic planes at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Spatiotemporal Evolution of Stress Field during Direct Laser Deposition of Multilayer Thin Wall of Ti-6Al-4V

et al. 2021

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The present work seeks to extend the level of understanding of the stress field evolution during direct laser deposition (DLD) of a 3.2 mm thick multilayer wall of Ti-6Al-4V alloy by theoretical and experimental studies. The process conditions were close to the conditions used to produce large-sized structures by the DLD method, resulting in specimens having the same thermal history. A simulation procedure based on the implicit finite element method was developed for the theoretical study of the stress field evolution. The accuracy of the simulation was significantly improved by using experimentally obtained temperature-dependent mechanical properties of the DLD-processed Ti-6Al-4V alloy. The residual stress field in the buildup was experimentally measured by neutron diffraction. The stress-free lattice parameter, which is decisive for the measured stresses, was determined using both a plane stress approach and a force-momentum balance. The influence of the inhomogeneity of the residual stress field on the accuracy of the experimental measurement and the validation of the simulation procedure are analyzed and discussed. Based on the numerical results it was found that the non-uniformity of the through-thickness stress distribution reaches a maximum in the central cross-section, while at the buildup ends the stresses are distributed almost uniformly. The components of the principal stresses are tensile at the buildup ends near the substrate. Furthermore, the calculated equivalent plastic strain reaches 5.9% near the buildup end, where the deposited layers are completed, while the plastic strain is practically equal to the experimentally measured ductility of the DLD-processed alloy, which is 6.2%. The experimentally measured residual stresses obtained by the force-momentum balance and the plane stress approach differ slightly from each other.

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“…2) is that, for the first time in stress diffractometry, it uses a PG002/Si220 double monochromator, consisting of a plate made of flat pyrolytic graphite with reflecting plane and a curved perfect silicon single crystal focusing in the horizontal plane with reflecting plane . The use of a double monochromator made it possible to reduce the level of background and place the monochromator and instrument closer to the exit from the reactor channel, thus increasing the lightgathering power of the instrument [7][8]. The monochromator outputs a monochromatic neutron beam with a wavelength of 1.55 Å, which increases the neutron penetration depth in ferritic steel [9] and is convenient for measuring stresses for most industrially used metals [7].…”

Section: Stress Neutron Diffractometermentioning

confidence: 99%

“…The use of a double monochromator made it possible to reduce the level of background and place the monochromator and instrument closer to the exit from the reactor channel, thus increasing the lightgathering power of the instrument [7][8]. The monochromator outputs a monochromatic neutron beam with a wavelength of 1.55 Å, which increases the neutron penetration depth in ferritic steel [9] and is convenient for measuring stresses for most industrially used metals [7]. A helium-filled PSD with a work-…”

Section: Stress Neutron Diffractometermentioning

confidence: 99%

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Measuring Residual Stresses in Vamas International Calibration Block with the Stress Diffractometer of Ir-8 Reactor

Karpov

Sumin

2019

Russ J Nondestruct Test

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The results of measuring residual strains/stresses in the VAMAS international calibration block with the STRESS neutron diffractometer installed in the horizontal channel of the IR-8 reactor at Kurchatov Institute are presented. The measurement results are in good agreement with calculated stress values. The measurements have shown that the STRESS diffractometer is comparable in terms of its capabilities for measuring stresses with state-of-the-art diffractometers installed on higher power reactors.

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A double-crystal monochromator for neutron stress diffractometry

Cited by 12 publications

References 13 publications

A Neutron Diffraction Study of the Effect Produced by the Direction of Crystal Growth on the Distribution of Residual Stresses in Austenite Steel Prisms Manufactured by Selective Laser Melting

A Neutron Diffraction Study of the Effect Produced by the Direction of Crystal Growth on the Distribution of Residual Stresses in Austenite Steel Prisms Manufactured by Selective Laser Melting

Spatiotemporal Evolution of Stress Field during Direct Laser Deposition of Multilayer Thin Wall of Ti-6Al-4V

Measuring Residual Stresses in Vamas International Calibration Block with the Stress Diffractometer of Ir-8 Reactor

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