Determination of Residual Stresses in Low Transformation Temperature (LTT -) Weld Metals using X-ray and High Energy Synchrotron Radiation

Bi-metallic piping welds are frequently used in light water nuclear reactors to connect ferritic steel pressure vessel nozzles to austenitic stainless steel primary cooling piping systems. An important aspect for the integrity of such welds is the presence of residual stresses. Measurement of these residual stresses presents a considerable challenge because of the component size and because of the material heterogeneity in the weld regions. The specimen investigated here was a thin slice cut from a full-scale bi-metallic piping weld mock-up. A similar mock-up had previously been investigated by neutron diffraction within a European research project called ADIMEW. However, at that time, due to the wall thickness of the pipe, stress and spatial resolution of the measurements were severely restricted. One aim of the present investigations by high energy synchrotron radiation and neutrons used on this thin slice was to determine whether such measurements would render a valid representation of the axial strains and stresses in the uncut large-scale structure. The advantage of the small specimen was, apart from the easier manipulation, the fact that measurement times facilitated a high density of measurements across large parts of the test piece in a reasonable time. Furthermore, the recording of complete diffraction patterns within the accessible diffraction angle range by synchrotron X-ray diffraction permitted mapping the texture variations. The strain and stress results obtained are presented and compared for the neutron and synchrotron X-ray diffraction measurements. A strong variation of the texture pole orientations is observed in the weld regions which could be attributed to individual weld torch passes. The effect of specimen rocking on the scatter of the diffraction data in the butt weld region is assessed during the neutron diffraction measurements.

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Formation of welding residual stresses in low transformation temperature (LTT) materials

Soldagem & Inspeção ◽

10.1590/s0104-92242009000100009 ◽

2009 ◽

Vol 14 (1) ◽

pp. 74-81 ◽

Cited By ~ 14

Author(s):

Thomas Kannengiesser ◽

Arne Kromm

Keyword(s):

Residual Stress ◽

Synchrotron Radiation ◽

Residual Stresses ◽

Transformation Temperature ◽

Steel Structures ◽

High Strength ◽

High Energy ◽

Phase Transformation Temperature ◽

Filler Materials ◽

Precise Knowledge

For the safety and cost efficiency of welded high-strength steel structures, precise knowledge of the level and distribution of welding- and cooling-specific stresses and residual stresses is essential, since they exert a decisive influence on strength, crack resistance, and finally on the bearable service load. This paper presents innovative filler materials, of which the phase transformation temperature was deliberately adjusted via the chemical composition. The transformation behaviour of these martensitic Low Transformation Temperature (LTT-) filler materials shows direct effects on the local residual stresses in the weld and the HAZ. These effects can purposefully be exploited to counteract the thermally induced shrinkage of the material and to produce significant compressive residual stresses in the weld. Comparative welding experiments were carried out on 690 MPa high-strength base materials using various LTT-filler materials. High energy synchrotron radiation was used for residual stress measurement. Particularly the use of high energy synchrotron radiation makes it possible to detect the residual stress condition fast without destruction of material. Thereby, residual stress depth gradients can be determined simultaneously without removing material. In steel, gradients of up to 150 µm can be resolved in such a way. Furthermore, the application of high energy radiation permits determination of residual stresses of any available residual austenite contents. Results show significant dependence of transformation temperatures on the resulting residual stress level and distribution.

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Microstructural Evolution of Monolithic Fuel Foils During Processing

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314092705 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C729-C729

Author(s):

Donald Brown ◽

Maria Okuniewski ◽

Bjorn Clausen ◽

Thomas Sisneros ◽

Levente Balogh

Keyword(s):

Dislocation Density ◽

Residual Stresses ◽

Weight Percent ◽

High Energy ◽

X Ray Diffraction ◽

X Ray ◽

Bonded Materials ◽

Processing Step ◽

Phase Stresses

Residual stresses are expected in monolithic, aluminum clad uranium 10 weight percent molybdenum (U-10Mo) nuclear fuel plates because of the large mismatch in thermal expansion between the two bonded materials. Previous high energy x-ray diffraction measurements successfully profiled the residual stresses in the U-10Mo, but were unable to probe either the Al cladding or the 15micron Zr diffusion prevention barrier due to poor grain statistics. Neutron diffraction, with its inherently more divergent incident be alleviates this problem and, moreover, allowed for the determination of the dislocation density and texture in all three phases. Several samples were examined as a function of processing step and the phase stresses, dislocation density and texture are monitored with respect to the processing conditions.

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Determination of the alloying content in the matrix of Zr alloys using synchrotron radiation microprobe X-ray fluorescence

Journal of Nuclear Materials ◽

10.1016/s0022-3115(03)00267-8 ◽

2003 ◽

Vol 321 (2-3) ◽

pp. 221-232 ◽

Cited By ~ 22

Author(s):

A Yilmazbayhan ◽

O Delaire ◽

A.T Motta ◽

R.C Birtcher ◽

J.M Maser ◽

...

Keyword(s):

Synchrotron Radiation ◽

X Ray ◽

The Matrix ◽

Zr Alloys

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Residual Stress Measurement around the Interface of Copper Bicrystal Deformed by Uniaxial Extension

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.64.125 ◽

2010 ◽

Vol 64 ◽

pp. 125-134

Author(s):

Hanabusa Takao ◽

Ayumi Shiro ◽

Tatsuya Okada

Keyword(s):

Residual Stress ◽

Synchrotron Radiation ◽

Grain Boundary ◽

Residual Stresses ◽

Uniaxial Extension ◽

Kink Band ◽

X Rays ◽

X Ray ◽

Kink Bands ◽

Crystal Orientations

Residual stresses of a copper bicrystal were measured by X-ray diffraction and synchrotron radiation. A copper bicrystal specimen with a 90-degree tilt boundary was fabricated by the Brigdman technique. After the plastic extension of 30%, kink bands developed in a deformed matrix along the grain boundary. In this study, we focused on the residual stress distribution along the transverse direction of the specimen surface and the residual stresses in deformed matrix and kink band near the grain boundary. Residual stresses were evaluated by the X-ray single crystal measurement method. Stereographic projections were used to determine crystal orientations of deformed regions. It was found that crystal orientations were different between the deformed matrix and the kink band. Residual stresses in the direction along the grain boundary were compressive in the vicinity of the boundary and tensile in the region apart from the boundary. Residual stresses in the kink band were large in compression in compared with those in the deformation matrix. The difference in the results between X-rays and synchrotron radiation suggests that there is a depth variation in the deformation and therefore the residual stress development.

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Protein–ligand complex structure from serial femtosecond crystallography using soaked thermolysin microcrystals and comparison with structures from synchrotron radiation

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798317008919 ◽

2017 ◽

Vol 73 (8) ◽

pp. 702-709 ◽

Cited By ~ 5

Author(s):

Hisashi Naitow ◽

Yoshinori Matsuura ◽

Kensuke Tono ◽

Yasumasa Joti ◽

Takashi Kameshima ◽

...

Keyword(s):

Synchrotron Radiation ◽

Room Temperature ◽

Complex Structure ◽

Binding Mode ◽

Ligand Complex ◽

X Ray ◽

Cell Parameters ◽

Serial Femtosecond Crystallography ◽

Small Molecule Ligand

Serial femtosecond crystallography (SFX) with an X-ray free-electron laser is used for the structural determination of proteins from a large number of microcrystals at room temperature. To examine the feasibility of pharmaceutical applications of SFX, a ligand-soaking experiment using thermolysin microcrystals has been performed using SFX. The results were compared with those from a conventional experiment with synchrotron radiation (SR) at 100 K. A protein–ligand complex structure was successfully obtained from an SFX experiment using microcrystals soaked with a small-molecule ligand; both oil-based and water-based crystal carriers gave essentially the same results. In a comparison of the SFX and SR structures, clear differences were observed in the unit-cell parameters, in the alternate conformation of side chains, in the degree of water coordination and in the ligand-binding mode.

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Diffuse x-ray scattering from InGaAs/GaAs quantum dots

MRS Proceedings ◽

10.1557/proc-799-z6.6/n8.6/t6.6 ◽

2003 ◽

Vol 799 ◽

Author(s):

Rolf Köhler ◽

Daniil Grigoriev ◽

Michael Hanke ◽

Martin Schmidbauer ◽

Peter Schäfer ◽

...

Keyword(s):

Quantum Dots ◽

Synchrotron Radiation ◽

Diffuse Scattering ◽

Data Evaluation ◽

X Ray ◽

X Ray Scattering ◽

Gaas Matrix ◽

Wetting Layers ◽

Ray Scattering

ABSTRACTMulti-fold stacks of In0.6Ga0.4As quantum dots embedded into a GaAs matrix were investigated by means of x-ray diffuse scattering. The measurements were done with synchrotron radiation using different diffraction geometries. Data evaluation was based on comparison with simulated distributions of x-ray diffuse scattering. For the samples under consideration ((001) surface) there is no difference in dot extension along [110] and [-110] and no directional ordering. The measurements easily allow the determination of the average indium amount in the wetting layers. Data evaluation by simulation of x-ray diffuse scattering gives an increase of Incontent from the dot bottom to the dot top.

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Thickness determination of thin solid films by angle-resolved X-ray fluorescence spectrometry using monochromatized synchrotron radiation

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms ◽

10.1016/0168-583x(94)00388-2 ◽

1995 ◽

Vol 97 (1-4) ◽

pp. 407-411 ◽

Cited By ~ 6

Author(s):

W. Schmitt ◽

P. Drotbohm ◽

J. Rothe ◽

J. Hormes ◽

C.R. Ottermann ◽

...

Keyword(s):

Synchrotron Radiation ◽

Fluorescence Spectrometry ◽

Thin Solid Films ◽

X Ray ◽

Solid Films ◽

Thickness Determination

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In Situ Observation of Phase Transformations during Welding of Low Transformation Temperature Filler Material

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.3769 ◽

2010 ◽

Vol 638-642 ◽

pp. 3769-3774 ◽

Cited By ~ 20

Author(s):

Arne Kromm ◽

Thomas Kannengiesser ◽

Jens Gibmeier

Keyword(s):

Residual Stresses ◽

Phase Transformations ◽

Volume Change ◽

Transformation Temperature ◽

High Energy ◽

Filler Materials ◽

Transformation Temperatures ◽

Welding Processes ◽

Compressive Residual Stresses

Tensile residual stresses introduced by conventional welding processes diminish the crack resistance and the fatigue lifetime of welded components. In order to generate beneficial compressive residual stresses at the surface of a welded component, various post-weld treatment procedures are available, like shot peening, hammering, etc. These post-weld treatments are, however time and cost extensive. An attractive alternative is to generate compressive stresses over the complete weld joint in the course of the welding procedure by means of so-called Low Transformation Temperature (LTT) filler materials. The volume change induced by the transformation affects the residual stresses in the weld and its vicinity. LTT fillers exhibit a relatively low transformation temperature and a positive volume change, resulting in compressive residual stresses in the weld area. In-situ measurements of diffraction profiles during real welding experiments using Gas Tungsten Arc (GTA)-welding process were realized successfully for the first time. Transformation temperatures during heating and subsequent cooling of LTT welding material could be assessed by means of energy dispersive diffraction using high energy synchrotron radiation. The results show that the temperature of martensite start (Ms) is strongly dependent on the content of alloying elements. In addition the results indicate that different phase transformation temperatures are present depending on the welding depth. Additional determination of residual stresses allowed it to pull together time and temperature resolved phase transformations and the resulting phase specific residual stresses. It was shown, that for the evaluation of the residual stress state of LTT welds the coexisting martensitic and austenitic phases have to be taken into account when describing the global stress condition of the respective material in detail.

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