A Comparison study of the microstructure information in the Japanese sword obtained from the conventional destructive methods and the neutron Bragg-edge analysis

Oikawa, Kenichi   ; Watanabe, Kenichi*; Kiyanagi, Yoshiaki*; Sato, Hirotaka*; Ito, Masakazu*; Parker, J. D.*; Shinohara, Takenao   

Japanese swords, which have a history of about 1000 years, are interesting not only for their function as weapons and their lean beauty, but also for their advanced steel processing technology. In particular, the details of the manufacturing methods of Japanese swords before the 16th century are unknown due to oral tradition, and various destructive tests have been conducted until around the 1980s. In 1985, Takahashi et al. examined four Japanese sword cuttings from the Northern and Southern Dynasties and the early Edo Periods, and reported the macro- and microstructure, chemical composition, inclusions, and Vickers hardness distribution of the cross sections. In 2017, we conducted a neutron diffraction experiment on the same four-striped piece at Takumi at J-PARC, and clarified the differences in the distribution of carbon content in iron, as well as the distribution of crystallite size and dislocation density by Rietveld analysis and line-broadening analysis. In this study, we performed a Bragg edge imaging experiment on the same sample at RADEN at J-PARC to obtain information on the crystalline structure and the real space distribution of Vickers hardness obtained from the edge width. The details of the analysis results will be presented.