A unified evaluation of fatigue crack growth rate in different gas environments and its application limits

• Project/Area Number: 22560085
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Kyushu University
• Principal Investigator: ODA Yasuji 九州大学, 工学研究院, 助教 (20091340)
• Research Collaborator: NISHIMOTO Atsushi 九州大学, 大学院・工学府
• Project Period (FY): 2010 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2012: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2011: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2010: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: 金属疲労 / き裂伝ぱ速度 / 水素 / すべり / その場観察 / 環境疲労 / き裂伝ぱ

Research Abstract

High acceleration of the fatigue crack growth rate of carbon steel in hydrogen environment is due to transition from ductile fracture to quasi-cleavage(QC) fracture and to increase in area ratio of QC fracture surface. Loading frequency influences the transition behavior and QC area ratio. There exist conditions where ductile fracture has high proportion of the fracture surface and low acceleration of fatigue crack growth rate in nitrogen environment as well as in hydrogen. Usual fatigue crack growth test reveals not only ductile fracture surface but intergranular fracture surface even at the beginning of QC fracture. It was not successful to attempt to define the slip behaviordirectly related to the crack growth rate

Research Products

• [Journal Article] Loading Frequency Effects on the Fatigue Crack Growth Rate and Fracture Surface Morphology of Low carbon Steel in Case of Long-Term Use in Hydrogen Gas (2012)
  • Author(s): Atsushi NISHIMOTO, Yasuji ODA, Hiroshi NOGUCHI
  • Journal Title: Key Engineering Materials Volume: Vol.483-489 Pages: 323-326
  • DOI: 10.4028/www.scientific.net/kem.488-489.323
  • Peer Reviewed
• [Presentation] Loading Frequency Effects on the Fatigue Crack Growth Rate and Fracture Surface Morphology of Low carbon Steel in Case of Long-Term Use in Hydrogen Gas (2011)
  • Author(s): Atsushi NISHIMOTO, Yasuji ODA, Hiroshi NOGUCHI
  • Organizer: The 10th International Conference on Fracture Damage Mechanics(FDM 2011)
  • Place of Presentation: Dubrovnik, Croatia