Open Access
Article Number 07018
Number of page(s) 5
Section Applied Research and Applications: Applications
Published online 01 September 2009
ESOMAT 2009, 07018 (2009)
DOI: 10.1051/esomat/200907018

Study of Microstructures on Cross Section of JAPANESE SWORD

M. Yaso1, T. Takaiwa1, Y. Minagi1, K. Kubota1, 2, S. Morito1, 3, T. Ohba1, 3 and A. K. Das1, 3

1  Wakoh Museum, Yasugi-cho, Yasugi 692-0011, JAPAN
2  Metallurgical Research Laboratory, Hitachi Metals, Ltd., Yasugi-cho, Yasugi 692-8601, JAPAN
3  Department of Materials Science, Shimane University, Nishikawatsu, Matsue 690-8504, JAPAN

Published online: 1 September 2009

An old, famous Japanese sword has been studied metallurigically to observe its microstructure by optical microscopy and scanning electron microscopy. The microstructure in the sharp edge of cross-sectional part is fine martensite and the morphology is lath type martensite. The other parts of sword, side and central part, of cross section show the structure of fine pearlite or coarse pearlite dominantly. The hardness of the sharp edge is high enough to possess the sharp cutting property. SEM-EDX observations indicated that several kinds of non-metallic inclusions exist in the sword which are considered to be originated from the slag smelting reaction in Tatara process. The amount of non-metallic inclusions in the sword is 50-100 times more than that of the ordinary steel. In the sharp edge the amount of inclusions is fewer and the sizes are finer in comparison with side and central part of the sword. It is considered that repeatedly forging and folding operations in making sword process are responsible for that.

© Owned by the authors, published by EDP Sciences 2009