Speaker
Prof.
Yoshiaki Kiyanagi
(Nagoya University)
Description
The pulsed neutron transmission method is a unique method that can give crystallographic information non-invasively over a relatively wide area by analyzing the transmission spectrum of a sample reflecting the crystallographic characteristics(1). The transmission spectrum includes information on crystal structure, lattice spacing, strain, preferred orientation, and crystallite size. By applying this method to a Japanese sword, we successfully obtained such information. Trend of spatial changes of crystallite size and texture suggested that they were affected by hammering. Furthermore, we recently found that the Vickers hardness is proportional to widening of the lattice spacing distribution in martensite phase produced by quenching(2). This relation was applied to the cutting edge of a Japanese sword and obtained the Vickers hardness. The values were reasonable compared with the hardness obtained by a hardness meter for other swords. Sometimes we observed coarse grains in a metal and they gave single crystal-like dips in a transmission spectrum. Such coarse grain orientation will be determined by the dip analysis(3). Coarse grains may appear also in a Japanese sword and they will be analyzed by a similar method.
The pulsed neutron method is one of powerful tool for the research of metal cultural heritages to elucidate crystallographic characteristics and furthermore to guess unclear making process. Here, we present established and recent developed features of the method and some examples applied to Japanese swords.
(1) Y Kiyanagi, H Sato, T Kamiyama and T Shinohara, J. Physics, Conference Series 340, 012010 (2012).
(2) H. Sato, et al., Materials Transactions, 56, pp.1147 (2015).
(3) H. Sato, et al., submitted to J. App. Crystal.
Primary author
Prof.
Yoshiaki Kiyanagi
(Nagoya University)
