Hokkaido University · 재료과학
Shigeharu Ukai 교수의 연구실은 고온에서 뛰어난 기계적 강도와 방사선 저항성을 갖춘 산화물 분산 강화(ODS) 페라이트 스틸을 핵심으로, 고속 빠르기로운 원자로(Fast Reactor)용 연료 피복재 개발을 주요 연구 방향으로 삼고 있습니다. 특히, 나노미터 크기의 복합 산화물 입자와 고밀도의 불순물 복합체를 통해 기계적 강도를 극대화하고, 균일한 균열 저항성과 내구성을 확보하기 위한 열처리 및 가공 공정 최적화에 중점을 두고 있습니다. 연구는 고온에서의 피로 수명 연장과 형성성 향상을 위한 미세구조 제어, 특히 균열형상과 결정립 경계 특성 제어를 핵심 전략으로 삼고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
For use as fuel cladding of liquid metal fast reactors, Fe-0.12C-9Cr-2W ODS martensitic steel claddings were developed by cold-rolling under the softened ferrite phase induced by slow cooling from austenite phase, subsequently by ferrite to austenite phase transformation to break up substantially elongated grains produced by cold-rolling at the final heat-treatment. The produced claddings showed noticeable improvement in tensile and creep rupture strength that are considerably superior to PNC-FM
The high temperature strengthening mechanism of previously manufactured 12Cr-ODS ferritic steel claddings was clarified. In the recrystallized 12Cr-2W-0.3Ti-0.24Y2O3-ODS ferritic steel cladding, αY2TiO5 type complex oxide formation was responsible for the drastic reduction of oxide particle size and the resulting shortened distance between particles, which led to superior internal creep rupture strength at 973 K because of the high resistance to gliding dislocation. Internal creep deformation wa
As to an oxide dispersion strengthened (ODs) ferritic steel cladding as the promising candidate for long-life core materials of the fast reactors, previously fabricated claddings had inferior internal creep rupture strength in hoop direction and inferior formability due to less ductility. Those unexpected features of ODs claddings are substantially ascribed to the needle-like grain structure excessively elongated along the forming direction. Controlling the grain morphology by applying the recry
As to an oxide dispersion strengthened (ODs) ferritic steel cladding as the promising candidate for long-life core materials of the fast reactors, previously fabricated claddings had inferior internal creep rupture strength in hoop direction and inferior formability due to less ductility. Those unexpected features of ODs claddings are substantially ascribed to the needle-like grain structure excessively elongated along the forming direction. Controlling the grain morphology by applying the recry
The 9Cr-ODS martensitic steel claddings were developed by cold-rolling and subsequent heat-treatment. The standard chemical composition is Fe-0.13C-9Cr-2W-0.2Ti-0.35Y2O3. The substantially elongated grains formed by cold-rolling turned out to be into equi-axied grains by ferrite to austenite phase transformation at the final heat-treatment. The produced claddings have the tempered martensitic structure and excess oxygen of 0.060 mass%. The superior tensile and creep rupture strength were shown i
AbstractThe development status of 9Cr–oxide dispersion strengthened (ODS) ferritic steels was reviewed, focusing on the authors' activities. This material is the most prospective cladding of the advanced high burn-up fuel elements for Japanese prototype fast breeder reactor MONJU and international Generation IV advanced fast reactors, because of their inherent radiation resistance as well as superior high temperature strength. The Y2Ti2O7 complex oxide particles in nano-scale are precipitated th
