Comparative study of ancient and modern japanese swords using neutron tomography

Yoshihiro Matsumoto, Kenichi Watanabe, Kazuma Ohmae, Akira Uritani, Yoshiaki Kiyanagi, Hirotaka Sato, Masato Ohnuma, Anh Hoang Pham, Shigekazu Morito, Takuya Ohba, Kenichi Oikawa, Takenao Shinohara, Tetsuya Kai, Stefanus Harjo, Masakazu Ito

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have performed neutron tomography using two ancient Japanese swords (designated Morikage and Sukemasa) and one modern Japanese sword (Masamitsu) at RADEN in the J-PARC Materials and Life Science Experimental Facility. For the ancient Japanese sword Morikage, it is found that the martensite iron is distributed in the region of about 3 mm from the cutting-edge and the ferrite iron is distributed in the inner region of the blade. The martensite iron area surrounds the inner ferrite iron area. For the ancient Japanese sword Sukemasa, the martensite iron is distributed only in a very narrow region at the cutting-edge and the homogeneous ferrite iron area is dominantly distributed in the inner region of the blade. In contrast to the ancient Japanese swords, the distribution of the martensite iron is about 8 mm from the cutting-edge and is similar to the wave pattern visible on the blade surface for the modern Japanese sword Masamitsu. Additionally for Masamitsu, a region where the neutron transmittance slightly increases was found at the interface between the martensite area and inner ferrite iron area. Line-like structures due to inclusions produced in the manufacturing process were also found in the blade. These results indicate that the manufacturing processes and raw materials of the Japanese swords are significantly different depending on the era and place of manufacture. Going forward, it is necessary to compare systematically the internal structure of more samples in order to clarify historical changes in Japanese sword making, and the nondestructive approach using neutron tomography is one of the powerful tools to elucidate them.

Original languageEnglish
Title of host publicationNeutron Radiography - 11th World Conference on Neutron Radiography, WCNR 2018
EditorsFilomena Salvemini, Joseph J. Bevitt
PublisherAssociation of American Publishers
Pages221-226
Number of pages6
ISBN (Print)9781644900567
DOIs
Publication statusPublished - 2020
Externally publishedYes
Event11th World Conference on Neutron Radiography, WCNR 2018 - Sydney, Australia
Duration: Sep 2 2018Sep 7 2018

Publication series

NameMaterials Research Proceedings
Volume15
ISSN (Print)2474-3941
ISSN (Electronic)2474-395X

Conference

Conference11th World Conference on Neutron Radiography, WCNR 2018
Country/TerritoryAustralia
CitySydney
Period9/2/189/7/18

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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