Rietveld Texture Analysis for Metals Having Hexagonal Close‐Packed Phase by Using Time‐of‐Flight Neutron Diffraction at iMATERIA

Onuki, Yusuke; Hoshikawa, Akinori; Nishino, Seiji; Sato, Sadao; Ishigaki, Tōru

doi:10.1002/adem.201700227

Cited by 10 publications

(4 citation statements)

References 18 publications

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“…In a previous study [54], the phase fraction and crystallographic textures were precisely determined using Rietveld texture analysis [53] of TOF-ND data. Thus, the TOF-ND measurements at the iMATERIA, which can simultaneously evaluate the dislocation density, phase fraction, and texture, can potentially facilitate the comprehensive understanding of the strengthening mechanisms of EB-PBF Ti-6Al-4V alloys.…”

Section: Discussionmentioning

confidence: 99%

“…The ND-based texture analysis was used to calibrate and validate the developed elasto-plastic crystal plasticity model. Recently, by combining time-of-flight ND (TOF-ND) measurements and Rietveld texture analysis (RTA) [53], the β-phase fraction in an EB-PBF Ti-6Al-4V alloy was precisely determined [54]. Furthermore, a hierarchal texture evolution between the prior β-phase, acicular α-matrix, and β-phase at the α-interfaces was observed.…”

Section: Introductionmentioning

confidence: 99%

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Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Yamanaka

Mori

Onuki

et al. 2022

Metals

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Ti–6Al–4V alloys undergo a multiple phase transformation sequence during electron beam powder bed fusion (EB-PBF) additive manufacturing, forming unique dislocation substructures. Thus, determining the dislocation density is crucial for comprehensively understanding the strengthening mechanisms and deformation behavior. This study performed time-of-flight neutron diffraction (TOF-ND) measurements of Ti–6Al–4V alloys prepared via EB-PBF and examined the dislocation density in the as-built and post-processed states using convolutional multiple whole profile (CMWP) fitting. The present TOF-ND/CMWP approach successfully determined the bulk-averaged dislocation density (6.8 × 1013 m−2) in the as-built state for the α-matrix, suggesting a non-negligible contribution of dislocation hardening. The obtained dislocation density values were comparable to those obtained by conventional and synchrotron X-ray diffraction (XRD) measurements, confirming the reliability of the analysis, and indicating that the dislocations in the α-matrix were homogeneously distributed throughout the as-built specimen. However, the negative and positive neutron scattering lengths of Ti and Al, respectively, lowered the diffraction intensity for the Ti−6Al−4V alloys, thereby decreasing the lower limit of the measurable dislocation density and making the analysis difficult.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Yamanaka

Mori

Onuki

et al. 2022

Metals

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“…Several studies comparing ND results with other techniques, such as EBSD and XRD, show that this coverage is sufficient to determine the ODF [21,22]. More recently, several studies have determined ODFs from single-angle experiments making data collection at three angles a conservative approach [23,24]. The count time for each sample orientation was equivalent to 10 min of count time at a proton current of 100 µA, thus compensating for proton current fluctuations in the linear accelerator.…”

Section: Methodsmentioning

confidence: 99%

Through-Thickness Microstructure Characterization in a Centrifugally Cast Austenitic Stainless Steel Nuclear Reactor Primary Loop Pipe Using Time-of-Flight Neutron Diffraction

Schmitt

Savage

Wall

et al. 2021

QuBS

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The US code of Federal Regulations mandates regular inspection of centrifugally cast austenitic stainless steel pipe, commonly used in primary cooling loops in light-water nuclear power plants. These pipes typically have a wall thickness of ~8 cm. Unfortunately, inspection using conventional ultrasonic techniques is not reliable as the microstructure strongly attenuates ultrasonic waves. Work is ongoing to simulate the behavior of acoustic waves in this microstructure and ultimately develop an acoustic inspection method for reactor inspections. In order to account for elastic anisotropy in the material, the texture in the steel was measured as a function of radial distance though the pipe wall. Experiments were conducted on two 10 × 12.7 × 80 mm radial sections of a cast pipe using neutron diffraction scans of 2 mm slices using the HIPPO time-of-flight neutron diffractometer at the Los Alamos Neutron Science Center (LANSCE, Los Alamos, NM, USA). Strong textures dominated by a small number of austenite grains with their (100) direction aligned in the radial direction of the pipe were observed. ODF analysis indicated that up to 70% of the probed volume was occupied by just three single-grain orientations, consistent with grain sizes of almost 1 cm. Texture and phase fraction of both ferrite and austenite phases were measured along the length of the samples. These results will inform the development of a more robust diagnostic tool for regular inspection of this material.

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“…For the texture analysis, the Rietveld texture analysis using MAUD software was applied [12]. The authors have developed and optimized this analysis technique for iMATERIA diffractometer for texture studies for metallic materials as previously reported [13][14][15]. The Interpretations of the calculated pole figures and orientation distributions (OD) in Euler spaces were conducted by using MTEX software [16].…”

Section: Methodsmentioning

confidence: 99%

Anomalous Twinning as the Macroscopic Deformation Mechanism for AZ31 Magnesium Alloy

Onuki

Sato

2019

KEM

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In order to study the plastic deformation mechanism of AZ31 magnesium alloy, in situ texture measurement during uniaxial tensile deformation is conducted by using neutron diffraction. The specimen is prepared from a rolled sheet so that the deformation axis is parallel to the rolling direction. By increasing strain, the alignment of <10-10> along the tensile axis is strengthened, which is due to the activation of the prism slip system. The basal pole concentration at the prior sheet normal direction is slightly decreased by the deformation and the new texture component is formed at the transvers direction. This can be understood by activation of the {10-12} tension twinning. These results indicate that the tension twinning plays an important role even when the tensile deformation is applied parallel to the basal plane.

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Rietveld Texture Analysis for Metals Having Hexagonal Close‐Packed Phase by Using Time‐of‐Flight Neutron Diffraction at iMATERIA

Cited by 10 publications

References 18 publications

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Through-Thickness Microstructure Characterization in a Centrifugally Cast Austenitic Stainless Steel Nuclear Reactor Primary Loop Pipe Using Time-of-Flight Neutron Diffraction

Anomalous Twinning as the Macroscopic Deformation Mechanism for AZ31 Magnesium Alloy

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