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Takahashi, Toshiharu*; Minehara, Eisuke; Hajima, Ryoichi; Nishimori, Nobuyuki; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Iijima, Hokuto; Nishitani, Tomohiro; Okuda, Shuichi*
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.523 - 525, 2006/00
no abstracts in English
Takahashi, Toshiharu*; Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Iijima, Hokuto; Nishitani, Tomohiro; Okuda, Shuichi*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.498 - 500, 2005/07
no abstracts in English
Hajima, Ryoichi; Minehara, Eisuke; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Iijima, Hokuto; Nishitani, Tomohiro; Takahashi, Toshiharu*; Okuda, Shuichi*
Proceedings of 27th International Free Electron Laser Conference (FEL 2005) (CD-ROM), p.301 - 304, 2005/00
no abstracts in English
Matsuda, Yasuhiro*; Ueda, Yuji*; Nojiri, Hiroyuki*; Takahashi, Toshiharu*; Inami, Toshiya; Owada, Kenji; Murakami, Yoichi; Arima, Takahisa*
Physica B; Condensed Matter, 346-347, p.519 - 523, 2004/04
Times Cited Count：51 Percentile：86.07(Physics, Condensed Matter)A very small capacitor bank and miniature pulsed magnets have been developed to perform high-field synchrotron radiation experiments. A 20T pulsed field can be generated using an energy of 1kJ with typical pulse duration about 1ms. Electron spin resonance experiments in millimeter wave range and high-field X-ray diffraction experiments have been done successfully.
Wakai, Eiichi; Noto, Hiroyuki*; Shibayama, Tamaki*; Iwamoto, Yosuke; Ishida, Taku*; Sato, Koichi*; Yabuuchi, Atsushi*; Yoshiie, Toshimasa*; Takahashi, Toshiharu*; Kobayashi, Yasuhiro*; et al.
no journal, ,
In recent years, it has been reported that high-entropy alloys (HEA) have high strength but good ductility, and they are being researched and developed by cutting-edge research institutions around the world with the aim of finding various applications in progress. In this study, we considered several Fe-based, W-based, and Ti-based HEAs, excluding Co and Ni elements, in order to aim for use in high radiation fields and considering low-activation properties. These materials mainly have a bcc crystal structure and were fabricated using a melting method and their material properties were evaluated. As a result, it was found that Fe-based HEA has properties that exceed the hardness of pure W and has excellent irradiation resistance. In addition, a Ti-based HEA that can be subjected to high-temperature forging and high-temperature rolling has been found, and evaluation of the optimal heat treatment temperature is progressing. The hardness of W-based HEA increased through Hot Isostatic Pressing (HIP) treatment, and it was found to have the world's highest hardness among HEA materials.
Hajima, Ryoichi; Takahashi, Toshiharu*; Nagai, Ryoji; Sawamura, Masaru; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Iijima, Hokuto; Nishitani, Tomohiro; Okuda, Shuichi*; Minehara, Eisuke
no journal, ,
no abstracts in English
Wakai, Eiichi; Shibayama, Tamaki*; Noto, Hiroyuki*; Furuya, Kazuyuki*; Iwamoto, Yosuke; Wakui, Takashi; Makimura, Shunsuke*; Ishida, Taku*; Ando, Masami*; Sato, Koichi*; et al.
no journal, ,
In fields such as nuclear power and high-energy accelerator target systems, radiation causes degradation of materials and equipment, so materials with high durability and excellent functionality are expected to be created. High-entropy alloys (HEA) are expected to have high irradiation resistance and often have high strength and good ductility. In recent years, research and development is underway worldwide for various applications. In this study, Fe- and Ti-based and W-based HEAs composed of low activation elements (free of Ni and Co) were fabricated. These materials were subjected to X-ray diffraction, microstructural observation, hardness, magnetism, electrical resistance, STEM (or TEM, SEM) and EDS, ultrasonic measurements, and hot isostatic pressing (HIP). Ion irradiation, pulsed laser irradiation, and pulsed electron beam irradiation were also performed on some of the samples to investigate their response characteristics. These HEAs were much harder than normal alloys, and the magnetic properties and related microstructural analysis of Fe-based HEAs revealed that they have interesting properties such as micro magnetic domain structures. In particular, for Fe- and W-based HEAs, the changes in crystal structure, orientation, and internal microstructure induced by HIP treatment and the accompanying effects of high temperature and pressure had a significant effect on magnetic properties and material strength properties. Furthermore, the irradiation response properties of Fe-based HEAs have been characterized.
-phase based titanium alloysWakai, Eiichi; Ishida, Taku*; Kano, Sho*; Shibayama, Tamaki*; Sato, Koichi*; Noto, Hiroyuki*; Makimura, Shunsuke*; Furuya, Kazuyuki*; Yabuuchi, Atsushi*; Yoshiie, Toshimasa*; et al.
no journal, ,
Titanium materials have been applied to beam window materials and beam dumps in large accelerator systems because of their low specific gravity, high corrosion resistance, strength, and other advantages. As the beam power becomes higher, further improvement of irradiation resistance is required. We have investigated further the properties of titanium alloys based on the -phase, and it was found that Ti-15-3-3-3 alloys have excellent irradiation resistance when subjected to ion irradiation. In order to investigate the cause of this, microstructures and point defects in this and related materials were evaluated by TEM, positron lifetime measurement, electrical resistivity, and stress-induced changes, among others. In addition, we have recently begun to develop a prototype of a titanium-based high-entropy alloy based on -titanium, which is attracting worldwide attention and is being developed, and have also begun to evaluate the emotional properties of this alloy. We have examined the various properties of this material and found that it has considerably higher strength than conventional iron- and titanium-based materials.
