ISSN 0386-1678 REPORT OF THE RESEARCH INSTITUTE OF INDUSTRIAL TECHNOLOGY NIHON UNIVERSITY Number 105 These publications are issued at irregular intervals. March 2021 The authors alone are responsible for the contents of these reports. All communication relating to these reports should be addressed to Research Institute of Industrial Technology, Nihon University. 2-1 Izumi-cho l-chome, Narashino-shi, Chiba, 275-8575 Japan EDITORIAL BOARD Chief Editor Masakazu FURUICHI professor Editorial Member Kazuhiko KAKUDA professor 複写をご希望の方へ 日本大学生産工学部では，本誌掲載著作物の複写複製および転載複製に係る著作権を学術著作権 Ryuichi SHIMOYAMA professor 協会に委託しています。当該利用をご希望の方は，学術著作権会（https://www.jaacc.org/）が提供 Yuji MORIMIYA professor している複製利用許諾システムもしくは転載許諾システムを通じて申請ください。 Shinya NISHIO professor 権利委託先 一般社団法人学術著作権協会 Keiichi SAKAMOTO professor 〒107─0052 東京都港区赤坂9─６─41 乃木坂ビル２F Hiroyoshi SHIOKAWA professor E-mail info＠jaacc.jp Kuninori SUZUKI professor 複写複製および転載複製以外の許諾（著作物の引用，翻訳等）に関しては，（社）学術著作権協会に Harue YAMAGATA professor 委託致しておりませんので，下記までお問い合わせください。 Hiromichi ASAMOTO associate professor 日本大学生産工学部研究事務課 Yukiyo KURIYAGAWA associate professor 〒275─8575 千葉県習志野市泉町１─２─１ TEL 047─474─2276 FAX 047─474─2292 Tomohiko SATO associate professor E-mail cit.research＠nihon-u.ac.jp Daisuke TAKAHASHI assistant professor URL http://www.cit.nihon-u.ac.jp/research Yukari YAMAUCHI assistant professor Reprographic Reproduction outside Japan Shuhei KATO assistant professor Making a copy of this publication College of Industrial Technology, Nihon University authorized Japan Academic Association for Copyright Clearance (JAC) to license our reproduction rights and reuse rights of copyrighted works. If you wish to obtain permissions of these rights in the countries or regions outside Japan, please refer to the website of JAC (http://www.jaacc.org/en/) and confirm appropriate organiza- tions to request permission. Obtaining permission to quote, translate, etc. Please contact the copyright holder directly. Japan Academic Association for Copyright Clearance (JAC) Address 9─6─41 Akasaka, Minato─ku, Tokyo 107─0052 Japan Website https://www.jaacc.org/en/ Publication March 20, 2021 E-mail info＠jaacc.jp Research Institute of Industrial Technology Nihon University Address 2-1 Izumi-cho l-chome, Narashino-shi, Chiba, 275-8575 Japan TEL +81-47-474-2276 FAX +81-47-474-2292 E-mail [email protected] URL http://www.cit.nihon-u.ac.jp/research INDEX Masakatsu MAEDA 2 Professor, Department of Mechanical Engineering Hitoshi TSUNASHIMA 4 Professor, Department of Mechanical Engineering Tomohiro SEKI 6 Professor, Department of Electrical and Electronic Engineering Akira UCHIDA 8 Professor, Department of Electrical and Electronic Engineering Tomohito ASAKA 10 Associate Professor, Department of Civil Engineering Yosuke KANO 12 Associate Professor, Department of Civil Engineering Hiroyoshi SHIOKAWA 14 Professor, Department of Architecture and Architectural Engineering Kosei MIKAMI 16 Associate Professor, Department of Architecture and Architectural Engineering Kazuaki YOSHIMUNE 18 Professor, Department of Applied Molecular Chemistry Yohei YAMANE 20 Associate Professor, Department of Applied Molecular Chemistry Kuninori SUZUKI 22 Professor, Department of Industrial Engineering and Management Jun Toyotani 24 Professor, Department of Industrial Engineering and Management Kazuhiko KAKUDA 26 Professor, Department of Mathematical Information Engineering Yoshihiro NAKAMURA 28 Professor, Department of Mathematical Information Engineering Osamu IMAMURA 30 Associate Professor, Department of Sustainable Engineering Takashi NONAKA 32 Associate Professor, Department of Sustainable Engineering Kiminori NAKAZAWA 34 Professor, Department of Conceptual Design Atsushi ENTA 36 Lecturer, Department of Conceptual Design Atsushi SHIOMI 38 Associate Professor, Department of Liberal Arts and Basic Sciences Masaki TAKAYOSE 40 Associate Professor, Department of Liberal Arts and Basic Sciences － －1 Masakatsu MAEDA Professor, Department of Mechanical Engineering Masakatsu Maeda is a professor at the Department of Mechanical Engineering, College of Industrial Technology, Nihon University. He received his bachelor and master degrees in materials science and engineering from Osaka University in 1992 and 1994, respectively, and his doctor degree in engineering from Osaka University in 2004. His research interests are on controlling the behaviors and properties of materials interfaces by solid state processing. He is conducting fundamental studies on solid state welding of refractory materials, semiconductors, and dissimilar materials, friction stir welding of aluminum alloys, synthesis of non-equilibrium materials and microstructures, ultrasonic bonding of heat-labile materials, Ohmic contact formation for wide-bandgap compound semiconductors, and precise boring of semiconductor materials. He worked at the Joining and Welding Research Institute, Osaka University from 1994 to 2014 and moved to Nihon University in 2014 to spread the solid-state materials processing technology and to provide solutions to various processes by demonstrating the technology. He is a member of the Japan Welding Society, the Japan Society of Mechanical Engineers, the Japan Institute of Metals and Materials, the Japan Light Metal Welding Association, the Japan Institute of Light Metals, the Japan Society for Technology of Plasticity, and two other academic and/or industrial societies. Research Achievements 1) Solid-State Diffusion Bonding of Silicon Nitride Using Titanium Foils, Metallurgical and Materials Transactions A, 34A(8), 1647-1656, 2003. 2) Temperature Field in the Vicinity of FSW-Tool during Friction Stir Welding of Aluminium Alloys, Welding in the World, 49(3/4), 69-75, 2005. 3) Interfacial Microstructure and Thermal Stability of Zr55Cu30Ni5Al10 Metallic Glass Joints Formed by Ultrasonic Bonding, Materials Transactions, 50(6), 1263-1268, 2009. 4) Anomalous microstructure formed at the interface between copper ribbon and tin-deposited copper plate by ultrasonic bonding, Microelectronics Reliability, 51(6), 130-136, 2010. 5) Interfacial microstructure between thick aluminium wires and aluminium alloy pads formed by ultrasonic bonding, Science and Technology of Welding and Joining, 18(2), 103-107, 2013. The figure on the right shows the temperature distribution during friction stir welding (FSW) of A7075-T6 aluminum alloy plates under the tool rotation speed and the welding speed of 1800 rpm and 2.5 mm/s, respectively. It is clearly observed that the isothermal contours of both top and bottom surfaces are expanded to the advancing side, i.e., the temperature at a point on the advancing side reaches higher than that at the corresponding point on the retreating side. Such an asymmetry in the temperature distribution during FSW appears even if the materials to be welded are the same. It is one of the unique properties of FSW compared to other ordinary welding techniques. As a result of the asymmetric process of FSW, the structure and mechanical properties of the joints on the advancing and retreating sides appear different. The difference become more obvious in FSW of dissimilar materials. Research themes to establish dissimilar materials welding technology are now being conducted. － －2 Published Paper Friction stir welding of thin 1050 aluminum sheet by heat assisted tool Masaru TERAI, Masakatsu MAEDA and Kazuyoshi KATOH It has been proven by many researchers that aluminum alloys, which are known to be difficult to weld by conventional welding techniques, are successfully welded by friction stir welding (FSW). In addition, FSW is a solid-state welding process. The structure in the weld nugget is free of segregation caused by solidification, which indicates that it is suitable for welding dissimilar and/or composite materials. In FSW, a tool consisting of a shoulder and a probe is used. The tool plays two important roles simultaneously during welding: one is to generate heat by friction between the tool and the materials to be welded, and the other role is to form a direct metal-to-metal contact by inducing a plastic flow of the softened material. The objective of this study is to relieve the FSW tool from one of its main role: to generate heat by friction. 1-mm-thick 1050-H24 aluminum sheets were friction stir welded using a heater-embedded FSW tool. It is demonstrated that butt welding of the sheets becomes successful even at a low rotational speed of 60 rpm under the assist-heating of the FSW tool. The fact indicates that it is possible to weld without frictional heat. Sound joints with the highest average fracture strength, which is equivalent to that of the base metal, was obtained under the welding speed of 0.5 mm/s and the tool rotational speed of 60 rpm. The temperature of the sheet does not exceed 400 K throughout the welding under this condition. This temperature is 60 K lower than the ordinary FSW in which assist- heating is not used. In this way, freeing the FSW tool from frictional heat generation allows optimization of the relation between the temperature of the materials and the plastic flow rate and achieves welding at lower temperature. One of the microstructural features in heat-assisted FSW is that the widths of heat affected zone (HAZ) and thermo-mechanically affected zone are suppressed, compared to the ordinary FSW. Particularly, HAZ becomes almost negligible. The hardness profile shows the maximum at the stir zone without revealing HAZ softening. Keywords: FSW, assist heating, industrial pure aluminum, mechanical properties, rotational speed 補助加熱したツールによる1050