Zirconium effect on the microstructure with 14Cr-4Al ODS ferritic steels

14Cr-4Al系ODSフェライト鋼の組織に及ぼすジルコニウムの影響

Isselin, J.*; Vogt, G.*; 笠田 竜太*; 木村 晃彦*; 奥田 隆成*; 井上 賢紀 ; 鵜飼 重治*; 大貫 惣明*; 藤澤 敏治*; 阿部 冨士雄*

Isselin, J.*; Vogt, G.*; Kasada, Ryuta*; Kimura, Akihiko*; Okuda, Takanari*; Inoue, Masaki; Ukai, Shigeharu*; Onuki, Somei*; Fujisawa, Toshiharu*; Abe, Fujio*

Oxide dispersion-strengthened(ODS) ferritic steels are considered as very good candidates for the next generation fission energy production. Such materials have a good radiation resistance, high creep strength and a good swelling resistance. A High Cr and Al content gives a very good corrosion resistance even at very high temperature. In this study, the influence of the zirconium on the microstructure will be discussed. 2 ODS ferritic Zr content have been studied. Samples have been made from an extruded rod in the transversal direction and in the longitudinal direction. After mounting and polishing, the grain morphology has been studied with EBSD and the inclusions have been observed and analyzed with EPMA. Zr addition increases slightly the grain size. The transversal direction shows equiaxed grains and the longitudinal direction shows elongated grain. The grain morphology depends also on the position in the extruded rod: in the center of the rod, grains are bigger for both materials. The inclusion number is superior with the Zr-free ODS. Many inclusions are identified as aluminum oxides. However, the Zr added alloy shows important group of Zr precipitates oriented in the extrusion directions.