Microstructural analysis of mechanically tested reduced activation ferritc/martensitic steels

Tanigawa, Hiroyasu; Hirose, Takanori; Ando, Masami; Jitsukawa, Shiro; Kato, Yudai*; Koyama, Akira*

It has been a key issue to get the mechanical understanding of fracture process on microstructure basis, especially on neutron-irradiated materials, but not yet to be understood well enough as for the difficulty of making transmission electron microscope (TEM) thin film sample from mechanical-tested specimen. To solve this technical problem, the focused ion beam (FIB) micro-sampling system was installed to the Research Hot Laboratory of Japan Atomic Research Institute (JAERI), Japan. This system makes it possible to fabricate the TEM specimens from the critical points of mechanical-tested radioactive specimens, such as the crack initiation points of fatigue fracture on neutron irradiated specimen. In this paper, the microstructure of mechanical-tested specimen of Reduced Activation Ferritic/martensitic steels, RAFs are investigated focusing on the helium effects to fatigue fracture.