Misorientation Measurement of Individual Grains in Fatigue of Polycrystalline Alloys by Diffraction Contrast Tomography Using Ultrabright Synchrotron Radiation

2016 ◽  
Vol 879 ◽  
pp. 1355-1360 ◽  
Author(s):  
Yoshikazu Nakai ◽  
Daiki Shiozawa ◽  
Ryota Nakao ◽  
Naoya Asakawa ◽  
Shoichi Kikuchi
Keyword(s):  
Stainless Steel ◽  
Synchrotron Radiation ◽  
Austenitic Stainless Steel ◽  
Pure Iron ◽  
Polycrystalline Materials ◽  
Mapping Technique ◽  
Diffraction Contrast ◽  
Commercially Pure ◽  
Schmid Factor ◽  
Individual Grains

A three dimensional grain mapping technique for polycrystalline materials, called X-ray diffraction contrast tomography (DCT), was developed at SPring-8, which is the brightest synchrotron radiation facility in Japan. The developed technique was applied to a commercially pure iron and austenitic stainless steel. The shape and location of grains could be determined by DCT using the apparatus in a beam line of SPring-8. To evaluate the dislocation structure in fatigue, the total misorientation of individual grains was measured by DCT. The average value of the total misorientation over one sample was increased with the number of cycles. In a grain, the change of the total misorientation was largest for primary slip plane. For austenitic stainless steel (fcc), the change of the total misorientation in fatigue was larger for planes with larger Schmid factor, while it was not depended on the Schmid factor for commercially pure iron (bcc). This different behavior must come from planer slip in fcc structure and wavy slip in bcc structure.

Evaluation of Fatigue Damage by Diffraction Contrast Tomography Using Synchrotron Radiation

2014 ◽  
Vol 783-786 ◽  
pp. 2359-2364 ◽  
Author(s):  
Daiki Shiozawa ◽  
Yoshikazu Nakai ◽  
Ryotaro Miura ◽  
Shota Matsuda
Keyword(s):  
Synchrotron Radiation ◽  
Fatigue Damage ◽  
Grain Orientation ◽  
Three Dimensional ◽  
Mapping Technique ◽  
X Ray Diffraction ◽  
Diffraction Contrast ◽  
Three Dimensional Mapping ◽  
Grain Orientation Spread ◽  
Individual Grains

The three dimensional grain mapping technique for polycrystalline material, which is called X-ray diffraction contrast tomography (DCT) has proposed. In the present study, the measurement of DCT was conducted in SPring-8, which is the brightest synchrotron radiation facility in Japan, and the condition of measurement and data procedure are discussed. Developed technique was applied to aluminium alloy and stainless steel. The shape and location of grain could be determined by the developed three-dimensional mapping technique using the apparatus in a bending beam line of SPring-8. To evaluate plastic deformation, the grain orientation spreads of individual grains were measured. The grain orientation spread is caused by the mosaicity, which relates to the dislocation structure in a grain. The grain orientation spread was found to increase with increasing plastic strain. Fatigue damage also could be evaluated by the grain orientation spread in the DCT measurement.

Evaluation of Fatigue Damage by Diffraction Contrast Tomography Using Synchrotron Radiation

2014 ◽  
Vol 891-892 ◽  
pp. 600-605 ◽  
Author(s):  
Daiki Shiozawa ◽  
Yoshikazu Nakai ◽  
Ryotaro Miura ◽  
Shota Matsuda
Keyword(s):  
Synchrotron Radiation ◽  
Fatigue Damage ◽  
Grain Orientation ◽  
Three Dimensional ◽  
Mapping Technique ◽  
X Ray Diffraction ◽  
Diffraction Contrast ◽  
Three Dimensional Mapping ◽  
Grain Orientation Spread ◽  
Individual Grains

The three dimensional grain mapping technique for polycrystalline material, which is called X-ray diffraction contrast tomography (DCT) has proposed. In the present study, the measurement of DCT was conducted in SPring-8, which is the brightest synchrotron radiation facility in Japan, and the condition of measurement and data procedure are discussed. Developed technique was applied to aluminium alloy and stainless steel. The shape and location of grain could be determined by the developed three-dimensional mapping technique using the apparatus in a bending beam line of SPring-8. To evaluate plastic deformation, the grain orientation spreads of individual grains were measured. The grain orientation spread is caused by the mosaicity, which relates to the dislocation structure in a grain. The grain orientation spread was found to increase with increasing plastic strain. Fatigue damage also could be evaluated by the grain orientation spread in the DCT measurement.

3-Dimensional Characterization of Polycrystalline Bulk Materials Using High-Energy Synchrotron Radiation

2007 ◽  
Vol 539-543 ◽  
pp. 2353-2358 ◽  
Author(s):  
Ulrich Lienert ◽  
Jonathan Almer ◽  
Bo Jakobsen ◽  
Wolfgang Pantleon ◽  
Henning Friis Poulsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
High Energy ◽  
Mapping Technique ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
Reciprocal Space Mapping ◽  
3 Dimensional ◽  
Individual Grains

The implementation of 3-Dimensional X-Ray Diffraction (3DXRD) Microscopy at the Advanced Photon Source is described. The technique enables the non-destructive structural characterization of polycrystalline bulk materials and is therefore suitable for in situ studies during thermo-mechanical processing. High energy synchrotron radiation and area detectors are employed. First, a forward modeling approach for the reconstruction of grain boundaries from high resolution diffraction images is described. Second, a high resolution reciprocal space mapping technique of individual grains is presented.

scholarly journals Measured resolved shear stresses and Bishop-Hill stress states in individual grains of austenitic stainless steel

2017 ◽  
Vol 141 ◽  
pp. 388-404 ◽  
Author(s):  
Nicolai Ytterdal Juul ◽  
Jette Oddershede ◽  
Armand Beaudoin ◽  
Kamalika Chatterjee ◽  
Margaret K.A. Koker ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Shear Stresses ◽  
Stress States ◽  
Individual Grains

Measurement of Strain Distribution around Weld Zone for Railway Carbody Structure Using High-Energy Synchrotron Radiation

2008 ◽  
Vol 571-572 ◽  
pp. 321-326 ◽  
Author(s):  
Keisuke Matsumoto ◽  
Takahisa Shobu ◽  
Yoshiaki Akiniwa ◽  
Tsuyoshi Yagi ◽  
Masataka Yamamoto
Keyword(s):  
Stainless Steel ◽  
Synchrotron Radiation ◽  
Austenitic Stainless Steel ◽  
Laser Welding ◽  
Residual Strain ◽  
Strain Distribution ◽  
Weld Zone ◽  
High Energy ◽  
The Body ◽  
Scanning Method

The railway carbody structure for commuter and suburban train services in Japan is often made of austenitic stainless steel, which is used in the form of thin metal sheets manufactured by cold rolling. Spot welding and laser welding at lapped joints are used in the construction of such carbodies, but it is difficult to observe the strain distribution around these weld zones, which represent the critical area of the body structure’s strength. The objective of this study is to ascertain the strain distribution in the stainless steel around the weld zone of the carbody structure. To enable observation of this distribution, a strain scanning method using high-energy synchrotron radiation was applied to the strain measurement of austenitic stainless steel. The transmission method was applied in order to observe the internal weld zone. Using this method, we can measure the strain distribution from the surface to the inside of the weld zone. A lapped joint specimen, prepared by welding 2-mm-thick plates using the laser welding method, was used for measurement. Austenitic stainless steel generally poses problems in the measurement of strain due to its coarse grain and crystal texture. The gage volume in this measurement had a width of 3 mm and a height of 0.15 mm. The measurement provides the strain distribution of both residual strain and strain under loading, and the results obtained successfully show the distribution of strain in the weld zone. In addition, the differing tendency between the distribution of residual strain and that of strain under loading is clarified. The full width at half maximum (FWHM) value shows a difference between the tendency of the measured value of the weld zone and that of the base material.

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