Creep strengthening and weakening mechanisms by martensite lath in high Cr ferritic heat-resistant steel

• Project/Area Number: 24760576
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Kyushu University
• Principal Investigator: MITSUHARA Masatoshi 九州大学, 総合理工学研究科(研究院), 助教 (10514218)
• Project Period (FY): 2012-04-01 – 2014-03-31
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2013: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2012: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
• Keywords: フェライト系耐熱鋼 / クリープ変形 / 強化機構 / ラスマルテンサイト / 転位 / 粒界上析出物 / 電子顕微鏡 / 結晶方位解析 / 高Crフェライト系耐熱鋼

Research Abstract

In this study, we clarified creep strengthening and weakening mechanisms by martensite lath structure in high Cr ferritic heat resistant steel. Firstly, the interaction of dislocations and lath boundaries were observed with in-situ tensile test in high-voltage transmission electron microscope. Then, lath structure coarsening behavior during creep deformation was evaluated by the crystal orientation analysis. From these results, we concluded that lath structure is a dominant factor of creep strength in high Cr ferritic heat resistant steel. In addition, in order to understand the mechanism of improvement of lath structure stability by precipitates formed on grain boundary, the size and the density of precipitates on each grain boundary were estimated using the microstructural observation. Those parameters of precipitates obviously depended on the grain boundary character.

Research Products

• [Journal Article] 高Crフェライト系耐熱鋼のクリープ強度に対するラス境界の役割 (2013)
  • Author(s): 光原昌寿
  • Journal Title: 耐熱金属材料第123委員会研究報告 Volume: 54 Pages: 1-6
• [Journal Article] 高Crフェライト系耐熱鋼のクリープ強度に対するラス境界の役割 (2013)
  • Author(s): 光原昌寿
  • Journal Title: 耐熱金属材料123委員会研究報告 Volume: 54 Pages: 1-6
• [Presentation] An overview of micro/nano-structure and the creep property relationship of high-Cr heat resistant steels (2014)
  • Author(s): M. Mitsuhara
  • Organizer: Virginia Tech MSE Seminar
  • Place of Presentation: Virginia, USA
  • Year and Date: 2014-02-28
• [Presentation] Interaction between Dislocation and Lath Boundaries during High Temperature Deformation in 9Cr Heat-Resistant Steel (2014)
  • Author(s): M. Mitsuhara, M. Miake, S. Yamasaki, H. Nakashima, N. Nishida, J. Kusumoto, A. Kanaya
  • Organizer: TMS 2014, 143^<rd> Annual Meeting & Exhibition
  • Place of Presentation: California, USA
  • Year and Date: 2014-02-18
• [Presentation] Interaction between Dislocations and Lath Boundaries during High Temperature Deformation in 9Cr Heat-Resistant Steel (2014)
  • Author(s): Masatoshi Mitsuhara, Masaki Miake, Shigeto Yamasaki, Satoshi Hata, Hideharu Nakashima, Ninoru Nishida, Jun-ichi Kusumoto, Akihiro Kanaya
  • Organizer: TMS 2014, 143rd Annual Meeting & Exhibition
  • Place of Presentation: San Diego Convention Center, California, USA
  • Invited
• [Presentation] Effecto of Lath Boundary on Creep Strengthening in 9Cr Heat-Resistant Steel (2013)
  • Author(s): M. Mitsuhara, M. Miake, S. Yamasaki, H. Nakashima, N. Nishida, J. Kusumoto, A. Kanaya
  • Organizer: The 8^<th> International Conference on Processing & Manufacturing of Advanced Materials (THERMEC'2013)
  • Place of Presentation: Las Vegas, USA
  • Year and Date: 2013-12-03
• [Presentation] Effect of Lath Boundary on Creep Strengthening in 9Cr Hear-Resistant Steel (2013)
  • Author(s): Masatoshi Mitsuhara, Masaki Miake, Shigeto Yamasaki, Hideharu Nakashima, Ninoru Nishida, Jun-ichi Kusumoto, Akihiro Kanaya
  • Organizer: The 8th International Conference on Processing & Manufacturing of Advanced Materials (THERMEC’2013)
  • Place of Presentation: RIO Hotel, Las Vegas, USA
  • Invited
• [Presentation] An overview of micro/nano-structure and the creep property relationship of high-Cr heat resistant steels
  • Author(s): Masatoshi Mitsuhara
  • Organizer: Virginia Tech MSE Seminar
  • Place of Presentation: McBryde Hall, Virginia Tech, Virginia, USA
  • Invited