Takateru Yamamuro
Kumamoto University
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Featured researches published by Takateru Yamamuro.
Materials Science Forum | 2011
Akira Chiba; Yoshihito Kawamura; Minoru Nishida; Takateru Yamamuro
Metallic glass or amorphous alloys have been gaining popularity due to their low density, high strength, high fracture toughness, good corrosion and good wear resistance. Especially, bulk metallic glasses (BMGs), which are made in bulk form with a thickness of ~10mm at slow cooling rates of the order of 1~100K/s, have been noted as an industrial application. The welding to other materials becomes very important. Explosive welding of most popular Zr41.2Ti13.8Cu10Ni12.5Be22.5 bulk metallic glass to crystalline pure Cu plate is investigated in this paper and the BMG was found to retain the amorphous structure. The sound bonding with other materials is expected to push forward the application of BMGs for industrial usage.
Materials Science Forum | 2004
Yasuhiro Morizono; Minoru Nishida; Akira Chiba; Takateru Yamamuro
Explosive welding of titanium to hypoeutectoid steel (0.09 mass%C) was carried out, and interfacial aspects of as-welded and heat treated states have been investigated with a focus on microstructures of the steel. In as-welded joint, plastic flow occurred by high velocity collision was observed in the vicinity of the interface. The steel in the joints showed equiaxed structure consisting of ferrite and pearlite even after prolonged heat treatment up to 1173 K. Columnar grains were generated in the steel near the interface by the heat treatment at 1223 K and above. Although the region of the columnar ferrite structure increased with increasing heating temperature and holding time, texture with specific crystal orientation was not confirmed. It was found that such a microstructural change in the steel was closely related to constituent phases formed at the bonding interface. The formation mechanism of the columnar structure was also discussed.
Materials Science Forum | 2007
Yasuhiro Morizono; Minoru Nishida; Yoshikazu Kodama; Takateru Yamamuro; Yasuhide Ohno
Diffusion bonding of Ti and Ti-Al (Ti-10, 20 and 40 mol%Al) alloys to high carbon steel was carried out at 1073 and 1273 K for 3.6 ks in a vacuum. It has been found that the joint with Ti-20 mol%Al alloy is separated in the vicinity of the interface promptly after the bonding treatment at 1273 K. Such a phenomenon could not be observed in other Ti-Al alloy/steel joints, and the Ti-20 mol%Al alloy/steel joint bonded at 1073 K showed a high strength of about 170 MPa. Therefore, this phenomenon depends on the bonding temperature and the composition of the Ti-Al alloys. From the observation results of the interface, it is thought that the diffusion of constituent elements across the interface is part of the reason for the separation phenomenon. The separated surface of the Ti-20 mol%Al alloy side showed diffraction peaks of TiC phase by XRD. Its Vickers hardness was about 1200 and approximately 4 times higher than that before the bonding treatment. It is expected that the separation phenomenon at the Ti-20 mol%Al alloy/steel interface serves surface modification of titanium materials, which show poor wear resistance.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2004
Minoru Nishida; Yoshihito Kawamura; Takateru Yamamuro
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2006
Kousuke Fujishima; Minoru Nishida; Yasuhiro Morizono; Koichi Yamaguchi; Kentarou Ishiuchi; Takateru Yamamuro
Materials Transactions | 2004
Yasuhiro Morizono; Minoru Nishida; Akira Chiba; Takateru Yamamuro; Yusuke Kanamori; Takanobu Terai
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2006
Takateru Yamamuro; Yasuhiro Morizono; J. Honjyo; Minoru Nishida
Materials Transactions | 2007
Yasuhiro Morizono; Takateru Yamamuro; Minoru Nishida
Tetsu To Hagane-journal of The Iron and Steel Institute of Japan | 2012
Yasuhiro Morizono; Sadahiro Tsurekawa; Takateru Yamamuro
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2006
T. Nishiura; Takateru Yamamuro; D. Hashimoto; Yasuhiro Morizono; Minoru Nishida