Japanese-sword crystallographic study based on pulsed neutron imaging at J-PARC

Oikawa, Kenichi   ; Kiyanagi, Yoshiaki*; Sato, Hirotaka*; Pham, A.*; Watanabe, Kenichi*; Matsumoto, Yoshihiro*; Shinohara, Takenao   ; Kai, Tetsuya   ; Harjo, S.   ; Onuma, Masato*; Morito, Shigekazu*; Oba, Takuya*; Uritani, Akira*; Ito, Masakazu*

Japanese swords are paid great admiration in the world as the honor of classical technology and of the art. There have been many reports in the past that tried to elucidate this Japanese sword's microstructure or manufacturing process scientifically. These reports were mainly done by destructive testing methods, such as the microscopic and chemical analyses on the cross sections of swords after mechanical cutting and polishing. Neutron tomography and neutron diffraction are commonly used as a non-destructive investigating method to see inside of the object and evaluate its microstructure. In J-PARC, Bragg edge imaging, a 2D mapping method based on analysis of thousands of position-dependent transmission spectrum data, is actively used to elucidate the crystallographic structure of Japanese swords. Recent research project works by the authors using J-PARC instruments will be introduced.