Internal stress measurements by high-energy synchrotron X-ray diffraction at increased specimen-detector distance
01 Jan 2003-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms (North-Holland)-Vol. 200, pp 315-322
TL;DR: In this article, the authors present results obtained using a setup in which two area detectors are positioned at a large distance (7 m) from the specimen. But only segments of the rings can be recorded this way, this approach offers a number of advantages.
Abstract: High-energy X-ray diffraction has recently been shown to be a viable technique to measure volume-averaged lattice strains in the bulk of metallic polycrystals at increased speed compared to neutron diffraction. The established procedure is to irradiate the sample under investigation with monochromatic X-rays (∼100 keV) and to record complete diffraction rings with an area detector. The lattice strains are obtained by analyzing the minute distortions of these rings. In the present paper we present first results obtained using a setup in which two area detectors are positioned at a large distance (7 m) from the specimen. Although only segments of the rings can be recorded this way, this approach offers a number of advantages. In situ tensile tests were performed on a γ-TiAl-based alloy as an example to demonstrate the potential of the method. Both materials science aspects as well as consequences for further method development will be discussed.
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TL;DR: The combination of these techniques is a strong issue for the construction and development of future IoT-based infrastructures as discussed by the authors, and the combination of the techniques is an important issue for future IoT devices.
Abstract: The combination of these techniques is a strong issue for the construction and development of future
instruments.
186 citations
Cites methods from "Internal stress measurements by hig..."
...A full evaluation of this work has been published in an individual paper (Böhm et al., 2003)....
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...A full evaluation of this work has been published in an individual paper (Böhm et al., 2003)....
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...It has been shown that better accuracy can be achieved for strain analysis with the Debye–Scherrer method if a larger distance between the sample and the detectors is used (Böhm et al., 2003)....
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...Instead it has been demonstrated to register only part of the rings and to determine their curvature by a fitting method (Böhm et al., 2003)....
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...Instead it has been demonstrated to register only part of the rings and to determine their curvature by a fitting method (Böhm et al., 2003)....
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TL;DR: The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction, based on digital flat-panel technology combining an amorphous Si panel with a CsI scintillator, which allows for the acquisition of high-quality diffraction data at highX-ray energies.
Abstract: The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 × 2480 pixels with a pixel size of 154 µm × 154 µm, and thus it covers an effective area of 294 mm × 379 mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes.
87 citations
Cites background from "Internal stress measurements by hig..."
...…and low scattering angles allow for complex sample environments to be constructed for in situ analysis while also providing true bulk structural information of the sample (Bohm et al., 2003; Daymond & Withers, 1996; Korsunsky et al., 1998; Wanner & Dunand, 2000; Daniels, 2008; Jones et al., 2008)....
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25 Nov 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the spottiness of the Debye-Scherrer rings, showing reflections from individual crystallites, is analyzed to obtain grain statistics, mosaic spread and grain orientation.
Abstract: Well collimated, high energy X-rays of 90 keV from synchrotron sources have been used to study metals undergoing plastic deformation in situ, in real time and in the bulk of the materials. The spottiness of the Debye–Scherrer rings, showing reflections from individual crystallites, is analyzed to obtain grain statistics, mosaic spread and grain orientation. Upon cold deformation, coarse grained materials show fingerprints of subgrain formation, grain rotation, grain refinement and the evolution from a single grain into the asymptotic texture. Lattice strain, its partition and anisotropy can be simultaneously revealed. Heating of metals under continuous load drives the observation through the regimes of phase transformation and grain relationships therein, grain coarsening, dynamic recovery and dynamic recrystallization. Examples on copper, magnesium, twinning induced plasticity steel, zirconium alloy and titanium aluminium intermetallics are shown.
78 citations
TL;DR: In this article, hot compressive tests were conducted in a high-energy synchrotron x-ray beam to study in situ and in real time microstructural changes in the bulk of a β-solidifying titanium aluminide alloy.
Abstract: Hot-compression tests were conducted in a high-energy synchrotron x-ray beam to study in situ and in real time microstructural changes in the bulk of a β-solidifying titanium aluminide alloy. The occupancy and spottiness of the diffraction rings have been evaluated in order to access grain growth and refinement, orientation relationships, subgrain formation, dynamic recovery, and dynamic recrystallization, as well as phase transformations. This method has been applied to an alloy consisting of two coexisting phases at high temperature and it was found that the bcc β-phase recrystallizes dynamically, much faster than the hcp α-phase, which deforms predominantly through crystallographic slip underpinned by a dynamic recovery process with only a small component of dynamic recrystallization. The two phases deform to a very large extent independently from each other. The rapid recrystallization dynamics of the β-phase combined with the easy and isotropic slip characteristics of the bcc structure explain the ex...
55 citations
TL;DR: In this article, in situ high-energy X-ray diffraction measurements were conducted on a recent β-stabilised TNM sheet to study the loadbearing mechanisms and their sequential order upon tensile loading for the first time on the level of individual lattice planes and phases.
35 citations
References
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TL;DR: In this paper, the second-order elastic stiffness coefficients of a Ti{sub 44}Al{sub 56} single crystal (ital L}1{sub 0} structure were measured at room temperature using a resonant ultrasonic spectroscopy (RUS) technique.
Abstract: The six independent second-order elastic stiffness coefficients of a Ti{sub 44}Al{sub 56} single crystal ({ital L}1{sub 0} structure) have been measured at room temperature for the first time using a resonant ultrasonic spectroscopy (RUS) technique. These data were used to calculate the orientation dependence of Young`s modulus and the shear modulus. The Young`s modulus is found to reach a maximum near a [111] direction, close to the normal to the most densely packed planes. The elastic moduli and the Poisson`s ratio for polycrystalline materials, calculated by the averaging scheme proposed by Hill, are in good agreement with experimental data and theoretical calculations.
136 citations
TL;DR: In this paper, a synchrotron X-ray transmission technique was applied to study the internal load transfer and micromechanical damage in molybdenum particle-reinforced copper matrix composites during plastic deformation.
Abstract: A synchrotron X-ray transmission technique was applied to study the internal load transfer and micromechanical damage in molybdenum particle-reinforced copper matrix composites during plastic deformation. Mechanically loaded, 1.5-mm-thick specimens were irradiated with a monochromatic beam of 65 keV X-rays. Low-index diffraction rings of both phases were recorded with a high-resolution two-dimensional detector. By means of newly developed data processing routines, we could quantify as a function of applied stress both the ring distortion (from which the volume-averaged elastic strains in the two phases were calculated), and the ring graininess (which is related to the Bragg peak broadening). Based on this information, the deformation and damage processes in these alloys were studied in detail. As compared to conventional neutron diffraction methods, the photon transmission technique yielded similar precision but at much reduced measurement times. The main sources of experimental errors were identified and strategies to minimize these errors were developed.
105 citations
TL;DR: In this article, the authors used a high-resolution CCD camera to collect diffracted patterns in digital form using the ID11, BL2 material science beamline at theEuropean Synchrotron Radiation Facility at Grenoble.
94 citations
TL;DR: In this article, the first sets of engineering measurements made at the European Synchrotron Radiation facility (ESRF) achieving extremely fast measurement times and high strain resolution in transmission were reported.
59 citations
01 Dec 2001-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the lattice mismatch between the γ matrix and the precipitates in the AM1 superalloy was measured in situ during a creep experiment up to fracture (150 MPa, 1050 and 1080 °C) by high energy XRD at the ID 15 beamline of the ESRF.
Abstract: The lattice mismatch between the γ matrix and the γ′ precipitates in the AM1 superalloy was measured in situ during a creep experiment up to fracture (150 MPa, 1050 and 1080 °C) by high energy XRD at the ID 15 beamline of the ESRF. The results are coherent with experiments done post mortem on specimens just annealed, and a specimen strained at 1050 °C, 150 MPa up to 1.03%. From the evolution of the mismatch, it is proposed that the elastic interfacial energy varies strongly during a creep test, and might put a limit on the high temperature ductility of superalloys.
22 citations