Quantum Beam Science

Research

9 pages, 3866 KiB

Open AccessFeature PaperArticle

Internal Strain Distribution of Laser Lap Joints in Steel under Loading Studied by High-Energy Synchrotron Radiation X-rays

by Takahisa Shobu, Ayumi Shiro, Fumiaki Kono, Toshiharu Muramatsu, Tomonori Yamada, Masayuki Naganuma and Takayuki Ozawa

Quantum Beam Sci. 2021, 5(2), 17; https://doi.org/10.3390/qubs5020017 - 2 Jun 2021

Cited by 1 | Viewed by 3556

Abstract

The automotive industries employ laser beam welding because it realizes a high energy density without generating irradiation marks on the opposite side of the irradiated surface. Typical measurement techniques such as strain gauges and tube X-rays cannot assess the localized strain at a [...] Read more.

The automotive industries employ laser beam welding because it realizes a high energy density without generating irradiation marks on the opposite side of the irradiated surface. Typical measurement techniques such as strain gauges and tube X-rays cannot assess the localized strain at a joint weld. Herein high-energy synchrotron radiation X-ray diffraction was used to study the internal strain distribution of laser lap joint PNC-FMS steels (2- and 5-mm thick) under loading at a high temperature. As the tensile load increased, the local tensile and compressive strains increased near the interface. These changes agreed well with the finite element analysis results. However, it is essential to complementarily utilize internal defect observations by X-ray transmission imaging because the results depend on the defects generated by laser processing. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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15 pages, 4916 KiB

Open AccessFeature PaperArticle

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

by Matthew M. Schmitt, Daniel J. Savage, James J. Wall, John D. Yeager, Chanho Lee and Sven C. Vogel

Quantum Beam Sci. 2021, 5(2), 12; https://doi.org/10.3390/qubs5020012 - 7 May 2021

Viewed by 2886

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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14 pages, 23151 KiB

Open AccessFeature PaperArticle

Multiple Wavelengths Texture Measurement Using Angle Dispersive Neutron Diffraction at WOMBAT

by Pingguang Xu and Klaus-Dieter Liss

Quantum Beam Sci. 2021, 5(2), 11; https://doi.org/10.3390/qubs5020011 - 30 Apr 2021

Cited by 2 | Viewed by 3745

Abstract

In contrast to conventional angle dispersive neutron diffractometers with a single-tube detector or a small-size linear position-sensitive detector, the WOMBAT diffractometer of the Australian Nuclear Science and Technology Organisation (ANSTO) is equipped with a large-area curved position-sensitive detector, spanning 120° for the scattering [...] Read more.

In contrast to conventional angle dispersive neutron diffractometers with a single-tube detector or a small-size linear position-sensitive detector, the WOMBAT diffractometer of the Australian Nuclear Science and Technology Organisation (ANSTO) is equipped with a large-area curved position-sensitive detector, spanning 120° for the scattering angle 2θ and 15° for the azimuth η, respectively. Here, WOMBAT was employed in establishing a texture measurement environment for complex textured samples, through measuring neutron diffractograms at two selected wavelengths on a typical reference sample of martensite–austenite multilayered steel sheet. All neutron patterns were simultaneously Rietveld analyzed using the software, Materials Analysis Using Diffraction (MAUD). The shorter wavelength (λ₁ = 1.54 Å, k₁ = 4.08 Å⁻¹) enabled collecting the martensite reflections α-110, α-200, α-211, α-220, α-310, and α-222, as well as the austenite peaks γ-111, γ-200, γ-220, γ-311, γ-222, and γ-331 simultaneously, by pre-setting the detector range to 2Θ = 30~150°. The longer wavelength (λ₂ = 2.41 Å, k₂ = 2.61 Å⁻¹) enabled separating the overlapping strong martensite α-110 and austenite γ-111 Laue–Bragg interferences more reliably. Moreover, the detector panel division along the vertical direction has a good stereographic coverage in the azimuthal angle η,. Such a combination of multiple-wavelength neutron diffraction combined with simultaneous Rietveld texture analysis was confirmed as being very valuable for realizing high precision measurements for complex textured samples at an orientation distribution graticule of 5°, and in a much shorter beam time than the conventional angle dispersive method. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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12 pages, 6871 KiB

Open AccessArticle

In Situ Observation for Deformation-Induced Martensite Transformation during Tensile Deformation of SUS 304 Stainless Steel by Using Neutron Diffraction PART II: Transformation and Texture Formation Mechanisms

by Yusuke Onuki and Shigeo Sato

Quantum Beam Sci. 2021, 5(1), 6; https://doi.org/10.3390/qubs5010006 - 2 Feb 2021

Cited by 9 | Viewed by 4075

Abstract

Herein, the texture developments of γ austenite, ε martensite, and α’ martensite during the tensile deformation of SUS 304 stainless steel were observed by using the in situ neutron diffraction technique. Combined with the microstructure and local orientations measured by electron backscattered [...] Read more.

Herein, the texture developments of γ austenite, ε martensite, and α’ martensite during the tensile deformation of SUS 304 stainless steel were observed by using the in situ neutron diffraction technique. Combined with the microstructure and local orientations measured by electron backscattered diffraction (EBSD), the mechanisms involved in the deformation-induced martensite transformation (DIMT) in the SUS 304 stainless steel were examined based on the neutron diffraction results. The results revealed that the ε martensite inherited the texture of the γ austenite, that is, their main components could be connected by Shoji–Nishiyama orientation relationship. The variant selection was qualitatively evaluated based on the Schmid factors of the

{111} ⟨ \bar{2} 11 ⟩

slip systems. The results revealed that the ε→α’ transformation occurred easily in the steel sample. Consequently, the volume fraction of the α’ martensite phase observed by EBSD was higher than that observed by neutron diffraction. In addition, at a true strain of 0.42, a packet structure consisting of two α’ martensite variants was observed in the steel sample. However, the original orientation of the variants did not correspond to the main components in the γ or ε phases. This suggests that the two α’ martensite variants were transformed directly from the lost component of the γ matrix. These results indicate that the γ→ε→α’ DIMT was first activated in the steel sample, after which the γ→α’ DIMT was activated at the later stage of deformation. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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12 pages, 6644 KiB

Open AccessArticle

Characterization of Dislocation Rearrangement in FCC Metals during Work Hardening Using X-ray Diffraction Line-Profile Analysis

by Koutarou Nakagawa, Momoki Hayashi, Kozue Takano-Satoh, Hirotaka Matsunaga, Hiroyuki Mori, Kazunari Maki, Yusuke Onuki, Shigeru Suzuki and Shigeo Sato

Quantum Beam Sci. 2020, 4(4), 36; https://doi.org/10.3390/qubs4040036 - 11 Oct 2020

Cited by 15 | Viewed by 4889

Abstract

Multiplication and rearrangement of dislocations in face-centered cubic (FCC) metals during tensile deformation are affected by grain size, stacking fault energy (SFE), and solute elements. X-ray diffraction (XRD) line-profile analysis can evaluate the dislocation density (

ρ

) and dislocation arrangement (M [...] Read more.

Multiplication and rearrangement of dislocations in face-centered cubic (FCC) metals during tensile deformation are affected by grain size, stacking fault energy (SFE), and solute elements. X-ray diffraction (XRD) line-profile analysis can evaluate the dislocation density (

ρ

) and dislocation arrangement (M) from the strength of the interaction between dislocations. However, the relationship between M and

ρ

has not been thoroughly addressed. In this study, multiplication and rearrangement of dislocations in FCC metals during tensile deformation was evaluated by XRD line-profile analysis. Furthermore, the effects of grain size, SFE, and solute elements on the extent of dislocation rearrangement were evaluated with varying M values during tensile deformation. M decreased as the dislocation density increased. By contrast, grain size and SFE did not exhibit a significant influence on the obtained M values. The influence of solute species and concentration of solute elements on M changes were also determined. In addition, the relationship between dislocation substructures and M for tensile deformed metals were also explained. Dislocations were loosely distributed at M > 1, and cell walls gradually formed by gathering dislocations at M < 1. While cell walls became thicker with decreasing M in metals with low stacking fault energy, thin cell walls with high dislocation density formed for an M value of 0.3 in metals with high stacking fault energy. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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15 pages, 3164 KiB

Open AccessFeature PaperArticle

Measurement of the X-ray Elastic Constants of Amorphous Polycarbonate

by Yuki Kawamura and Yoshiaki Akiniwa

Quantum Beam Sci. 2020, 4(4), 35; https://doi.org/10.3390/qubs4040035 - 9 Oct 2020

Cited by 3 | Viewed by 3057

Abstract

In polymer materials, residual stress introduced during injection molding affects yield reduction due to deformation during molding and delayed fracture during operation, so the establishment of nondestructive stress evaluation of polymer products is desirable. The X-ray elastic constants of polycarbonate were measured for [...] Read more.

In polymer materials, residual stress introduced during injection molding affects yield reduction due to deformation during molding and delayed fracture during operation, so the establishment of nondestructive stress evaluation of polymer products is desirable. The X-ray elastic constants of polycarbonate were measured for the purpose of obtaining fundamental data for X-ray stress measurement of amorphous polymer materials. The structural function was obtained from the diffraction data, and the strain measured by X-ray was determined from the shift of the first peak by the Q-space method. The peak position was determined using the pseudo-Voigt function approximation method and the diffraction line width method. The Young’s modulus measured by X-ray obtained by the diffraction line width method was close to the mechanical value. Although these values varied widely, they changed depending on the peak ratio. A simple and practical measurement method directly using the raw profile data was also discussed. The Young’s modulus determined by the diffraction line width method decreased with increasing peak ratio. On the other hand, the values determined by the pseudo-Voigt method were almost constant, irrespective of the peak ratio. The strain calculated by the line width method was determined more accurately than that by the pseudo-Voigt method. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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10 pages, 4790 KiB

Open AccessFeature PaperArticle

In Situ Observation for Deformation-Induced Martensite Transformation (DIMT) during Tensile Deformation of 304 Stainless Steel Using Neutron Diffraction. PART I: Mechanical Response

by Yusuke Onuki and Shigeo Sato

Quantum Beam Sci. 2020, 4(3), 31; https://doi.org/10.3390/qubs4030031 - 11 Sep 2020

Cited by 5 | Viewed by 3410

Abstract

304 stainless steel is one of the most common stainless steels due to its excellent corrosion resistance and mechanical properties. Typically, a good balance between ductility and strength derives from deformation-induced martensite transformation (DIMT), but this mechanism has not been fully explained. In [...] Read more.

304 stainless steel is one of the most common stainless steels due to its excellent corrosion resistance and mechanical properties. Typically, a good balance between ductility and strength derives from deformation-induced martensite transformation (DIMT), but this mechanism has not been fully explained. In this study, we conducted in situ neutron diffraction measurements during the tensile deformation of commercial 304 stainless steel (at room temperature) by means of a Time-Of-Flight type neutron diffractometer, iMATERIA (BL20), at J-PARC MLF (Japan Proton Accelerator Research Complex, Materials and Life Science Experimental Facility), Japan. The fractions of α′-(BCC) and ε-(HCP) martensite were quantitatively determined by Rietveld-texture analysis, as well as the anisotropic microstrains. The strain hardening behavior corresponded well to the microstrain development in the austenite phase. Hence, the authors concluded that the existence of martensite was not a direct cause of hardening, because the dominant austenite phase strengthened to equivalent values as in the martensite phase. Moreover, the transformation-induced plasticity (TRIP) mechanism in austenitic steels is different from that of low-alloy bainitic TRIP steels. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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17 pages, 4930 KiB

Open AccessArticle

Ovine Bone Morphology and Deformation Analysis Using Synchrotron X-ray Imaging and Scattering

by Eugene S. Statnik, Alexey I. Salimon, Cyril Besnard, Jingwei Chen, Zifan Wang, Thomas Moxham, Igor P. Dolbnya and Alexander M. Korsunsky

Quantum Beam Sci. 2020, 4(3), 29; https://doi.org/10.3390/qubs4030029 - 9 Aug 2020

Cited by 8 | Viewed by 3496

Abstract

Bone is a natural hierarchical composite tissue incorporating hard mineral nano-crystals of hydroxyapatite (HAp) and organic binding material containing elastic collagen fibers. In the study, we investigated the structure and deformation of ovine bone by the combination of high-energy synchrotron X-ray tomographic imaging [...] Read more.

Bone is a natural hierarchical composite tissue incorporating hard mineral nano-crystals of hydroxyapatite (HAp) and organic binding material containing elastic collagen fibers. In the study, we investigated the structure and deformation of ovine bone by the combination of high-energy synchrotron X-ray tomographic imaging and scattering. X-ray experiments were performed prior to and under three-point bending loading by using a specially developed in situ load cell constructed from aluminium alloy frame, fast-drying epoxy resin for sample fixation, and a titanium bolt for contact loading. Firstly, multiple radiographic projection images were acquired and tomographic reconstruction was performed using SAVU software, following segmentation using Avizo. Secondly, Wide Angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) 2D scattering patterns were collected from HAp and collagen. Both sample shape and deformation affect the observed scattering. Novel combined tomographic and diffraction analysis presented below paves the way for advanced characterization of complex shape samples using the Dual Imaging and Diffraction (DIAD) paradigm. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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14 pages, 7004 KiB

Open AccessFeature PaperArticle

Phase Stress Measurement of Centrifugally Cast Duplex Stainless Steel by Neutron Diffraction

by Yun Wang

Quantum Beam Sci. 2020, 4(3), 28; https://doi.org/10.3390/qubs4030028 - 29 Jul 2020

Cited by 164 | Viewed by 3093

Abstract

Residual stress can be easily generated during material processing and affect the performance of structural components. Phase stress distribution in austenitic-ferritic duplex stainless steels (DSSs) is complicated due to the different material properties between the two phases. In this study, residual phase stress [...] Read more.

Residual stress can be easily generated during material processing and affect the performance of structural components. Phase stress distribution in austenitic-ferritic duplex stainless steels (DSSs) is complicated due to the different material properties between the two phases. In this study, residual phase stress distribution along the thickness direction of centrifugally cast DSS hollow cylinder was measured by pulsed neutron diffraction with the time-of-flight (TOF) method. The triaxial phase stress distribution along the thickness direction shows that the phase stress of austenitic phase is generally in tension and higher than that of ferrite phase. From the outer surface to the inner surface, the macro-stress distributes from −400 MPa to 200 MPa. The mechanism of macro-stress formation was deduced by taking into consideration the thermal shrinkage behavior during the cooling process of water quench after the solution heat treatment. Furthermore, the lattice strain and phase stress evolution under the uniaxial tensile loading was evaluated by in-situ neutron diffraction measurement. The results indicated that the magnitude of phase stress could be affected by plastic working as well. All these measurements were conducted at Japan Proton Accelerator Research Complex (J-PARC). Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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14 pages, 2070 KiB

Open AccessArticle

Double-Exposure Method with Synchrotron White X-ray for Stress Evaluation of Coarse-Grain Materials

by Kenji Suzuki, Ayumi Shiro, Hidenori Toyokawa, Choji Saji and Takahisa Shobu

Quantum Beam Sci. 2020, 4(3), 25; https://doi.org/10.3390/qubs4030025 - 9 Jul 2020

Cited by 6 | Viewed by 3205

Abstract

Stress measurements of coarse-grained material are difficult using synchrotron X-ray diffraction because the diffraction patterns of coarse-grained materials are spotty. In addition, the center of the diffraction pattern is unknown for the transmitted X-ray beam. Here, a double-exposure method is proposed as the [...] Read more.

Stress measurements of coarse-grained material are difficult using synchrotron X-ray diffraction because the diffraction patterns of coarse-grained materials are spotty. In addition, the center of the diffraction pattern is unknown for the transmitted X-ray beam. Here, a double-exposure method is proposed as the countermeasure against this issue. In the experiment, we introduce a CdTe pixel detector. The detector is a newly developed area detector and can resolve high-energy X-rays. The strains of the coarse-grained material can be measured using a combination of the double-exposure method, white synchrotron X-ray, and the CdTe pixel detector. The bending stress in an austenitic stainless steel plate was measured using the proposed technique. As a result, the measured stress corresponded to the applied bending stress. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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13 pages, 5079 KiB

Open AccessFeature PaperArticle

Residual Stresses Induced by Surface Working and Their Improvement by Emery Paper Polishing

by Makoto Hayashi

Quantum Beam Sci. 2020, 4(2), 21; https://doi.org/10.3390/qubs4020021 - 14 May 2020

Cited by 8 | Viewed by 3419

Abstract

In many of machine parts and structural components, materials surface would be worked. In this study, residual stresses on the surfaces were measured by X-ray diffraction method, and effects of surface working on the residual stresses were examined. In case of lathe machining [...] Read more.

In many of machine parts and structural components, materials surface would be worked. In this study, residual stresses on the surfaces were measured by X-ray diffraction method, and effects of surface working on the residual stresses were examined. In case of lathe machining of type 304 stainless steel bar, the residual stresses in circumferential directions are tensile, and those in axial directions are almost compressive. Highly tensile residual stresses in the circumferential directions were improved by emery paper polishing. 10 to 20 times of polishing changes high tensile residual stresses to compressive residual stresses. In the case of shot peening on a type 304 stainless steel plate, the compressive residual stress inside is several hundred MPa lower than that on the surface. By applying the emery paper polishing to the shot peened surface 10 or 20 times, the residual stress on the surface is improved to −700 MPa. While fatigue strength at 288 °C in the air of the shot peened material is 30 MPa higher than solution heat treated and electro-polished material, the fatigue strength of the shot peened and followed by emery paper polished material is 60 MPa higher. Thus, the emery paper polishing is simple and a very effective process for improvement of the residual stresses. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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12 pages, 3886 KiB

Open AccessFeature PaperArticle

Residual Stress Distribution in Water Jet Peened Type 304 Stainless Steel

by Makoto Hayashi, Shinobu Okido and Hiroshi Suzuki

Quantum Beam Sci. 2020, 4(2), 18; https://doi.org/10.3390/qubs4020018 - 26 Mar 2020

Cited by 8 | Viewed by 3504

Abstract

In materials with a surface treatment such as shot peening, the residual stress gradient in the surface layer is severe. When measuring the residual stress distribution near the surface with a severe stress gradient by the neutron diffraction method, the gauge volume must [...] Read more.

In materials with a surface treatment such as shot peening, the residual stress gradient in the surface layer is severe. When measuring the residual stress distribution near the surface with a severe stress gradient by the neutron diffraction method, the gauge volume must be removed from the measurement sample. However, when the gauge volume deviates from the sample, a pseudo peak shift occurs and accurate stress distribution cannot be evaluated. Therefore, it is necessary to evaluate the pseudo peak shift in advance under the same conditions, as in the case of actual residual stress measurement, using a sample in an unstressed state. In this study, the stress distributions in the surface layer of a type 304 stainless steel plate and bar with simulated stress-corrosion cracks which were subjected to water jet peening—giving a surface layer residual stress equivalent better than that of normal shot peening—were evaluated considering the pseudo peak shift. As a result, the residual stress distributions in the surface layer were measured in good agreement with the measurement result obtained by the sequential polishing X-ray diffraction method. It was clarified that the residual stress distribution in the near surface with steep stress gradient can be evaluated by the neutron diffraction method. Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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14 pages, 7656 KiB

Open AccessFeature PaperArticle

Microstructural Features and Ductile-Brittle Transition Behavior in Hot-Rolled Lean Duplex Stainless Steels

by O. Takahashi, Y. Shibui, P.G. Xu, S. Harjo, T. Suzuki and Y. Tomota

Quantum Beam Sci. 2020, 4(1), 16; https://doi.org/10.3390/qubs4010016 - 5 Mar 2020

Cited by 6 | Viewed by 4942

Abstract

The characteristics of texture and microstructure of lean duplex stainless steels with low Ni content produced through hot rolling followed by annealing were investigated locally with electron backscatter diffraction and globally with neutron diffraction. Then, the ductile–brittle transition (DBT) behavior was studied by [...] Read more.

The characteristics of texture and microstructure of lean duplex stainless steels with low Ni content produced through hot rolling followed by annealing were investigated locally with electron backscatter diffraction and globally with neutron diffraction. Then, the ductile–brittle transition (DBT) behavior was studied by Charpy impact test. It is found that the DBT temperature (DBTT) is strongly affected by the direction of crack propagation, depending on crystallographic texture and microstructural morphology; the DBTT becomes extremely low in the case of fracture accompanying delamination. A high Ni duplex stainless steel examined for comparison, shows a lower DBTT compared with the lean steel in the same crack propagating direction. The obtained results were also discussed through comparing with those of cast duplex stainless steels reported previously (Takahashi et al., Tetsu-to-Hagané, 100(2014), 1150). Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams)

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