著者
松田 翔太 政田 尚也 塩澤 大輝 中井 善一 三浦 亮太郎
出版者
一般社団法人日本機械学会
雑誌
M&M材料力学カンファレンス
巻号頁・発行日
vol.2013, pp."OS1503-1"-"OS1503-3", 2013-10-12

X-ray diffraction contrast tomography (DCT) is a technique for three-dimensional grain mapping of polycrystalline material. Measurement of DCT has been conducted m SPring-8 and shape and location of grain can be determined by DCT technique using the apparatus in BL19B2. For evaluation of plastic deformation by DCT, tensile and cyclic loading was applied to the sample during the measurement of DCT. The diffraction spots belonging to certain grain appear over some continuous projection images. The rotation angle range where diffraction spot appear is defined as grain orientation spread, and the grain orientation spread was counted in tensile tests and fatigue test. In the tensile test, the grain orientation spread increases in the plastic deformation. In the fatigue test, grain orientation spread increases with increasing m the number of cycles. It is possible to evaluate fatigue damage by DCT technique and using the grain orientation spread.
著者
中井 善一 塩澤 大輝 松田 翔太 中尾 亮太 浅川 直也 菊池 将一
出版者
一般社団法人日本機械学会
雑誌
関西支部講演会講演論文集
巻号頁・発行日
vol.2015, pp.86-89, 2015

The three dimensional grain mapping technique for polycrystalline material, called X-ray diffraction contrast tomography (DCT), was conducted in SPring-8 (Super Photon ring-8 GeV), which is the brightest synchrotron radiation facility in Japan, and the conditions of measurement and data processing procedure have been obtained. Developed technique was applied to a commercially pure iron, and an austenitic stainless steel. The shape and location of grain could be determined by DCT using the apparatus in a beam line of SPring-8. Total misorientation of an individual crystalographic plane of a specific grain during fatigue test of the steels were measured. In fatigue test of the stainless steel, thetotal misorientastion of {111} planes increased with number of cyccles. Among {111} planes, the amount of change depended on Schmid factor, i.e., the change was higher for planes with larger Schmid factor. For the commercially pure iron, the total misorientastion of {110} planes increased with number of cyccles. The amount of change, however, did not depend on Schmid factor because of pencile-glide. The effect of cross-slip should be considered
著者
中尾 亮太 淺川 直也 松田 翔太 塩澤 大輝 菊池 将一 中井 善一
出版者
一般社団法人日本機械学会
雑誌
M&M材料力学カンファレンス
巻号頁・発行日
vol.2015, pp._GS0205-42-_GS0205-42, 2015

A three dimensional grain mapping technique for polycrystalline materials, called X-ray diffraction contrast tomography (DCT), was developed at SPring-8 (Super Photon ring-8 GeV), which is the brightest synchrotron radiation facility in Japan. To evaluate the fatigue damage of grains, total misorientation, β for each grain was calculated from DCT measurement. It is found that value of β increases with number of cycles, and change of β for primary slip plane is the largest in diffraction planes. In addition, the largest change of β, was observed in the diffraction plane with the largest Schmid factor, F_s in equivalent primary slip planes. From this results, it is found that change of β reflects slip behavior in a grain, because change of β correspond to Schmid factor in fcc materials which can be determined the primary slip direction.
著者
吉中 奎貴 中村 孝 髙久 和明 塩澤 大輝 中井 善一 上杉 健太朗
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 (ISSN:21879761)
巻号頁・発行日
vol.83, no.856, pp.17-00104-17-00104, 2017 (Released:2017-12-25)
参考文献数
23

The initiation and growth of internal small fatigue cracks with around ten or several dozen μm in Ti-6Al-4V were nondestructively examined by using synchrotron radiation μCT at the large synchrotron radiation facility SPring-8. Lots of grain-sized internal cracks were observed roughly evenly in the observation volume in the specimen; in contrast, only one surface crack was detected. The initiation lives of the internal cracks were widely different for each crack and had no significant correlation with the crack initiation site nor the initial crack size. The internal cracks propagated microstructure-sensitively with several crack deflections, and the growth rates were very small, less than 10-10 m/cycle. The crack growth rates just after facet formations showed large variability and had no apparent relationship with the crack initiation life nor the initial crack size. This variability can likely be attributed to microstructural inhomogeneities around the crack initiation facets. The estimated facet formation rate indicated that most facets formed rapidly compared with the following internal crack growth rate.
著者
中井 善一 塩澤 大輝 田中 拓
出版者
神戸大学
雑誌
基盤研究(B)
巻号頁・発行日
2011-04-01

本課題では,高輝度放射光のX線回折を用いたコンピュータトモグラフィ(DCT)法を開発し,アルミニウム合金およびステンレス鋼多結晶体の結晶粒の形状を三次元的に同定した.その結果,SPring-8の偏向電磁石を利用した汎用のビームラインでも,結晶粒の形状および位置を三次元的に同定することができた.各結晶粒の塑性ひずみを同定するため,結晶方位の拡がりを測定した.この結晶粒方位の拡がりは,転位構造と関連した結晶粒のモザイク性と関連しており,塑性ひずみの増加とともに結晶方位の拡がりが増加した.また,疲労過程中の損傷の蓄積もDCTによって測定することができた.