In order to clarify the mechanism of fatigue crack growth in alloy 625, which is a candidate material for use in advanced ultra supercritical power plants, the crack tip damage zone formation after a crack growth test conducted in high temperature steam was investigated. It was observed that the oxide thickness at the crack tip tended to increase with decreasing cyclic loading frequency. The crack path was a mix of transgranular and intergranular fractures. According to the grain reference orientation deviation (GROD) maps, it was revealed that the density of geometrically necessary dislocations (GNDs) in the matrix along the crack path and ahead of crack tip increased with an increase in the fatigue crack growth rate (FCGR) due to environmental effects. It was observed that (1) mobile dislocations at the crack surface were blocked due to the thick oxide layer, resulting in an increase in the density of GNDs, and (2) an increase in the density of GNDs might induce stress concentration at the crack tip, deformation twinning, and the acceleration of FCGRs.
Skip Nav Destination
ASME 2017 Power Conference Joint With ICOPE-17 collocated with the ASME 2017 11th International Conference on Energy Sustainability, the ASME 2017 15th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2017 Nuclear Forum
June 26–30, 2017
Charlotte, North Carolina, USA
Conference Sponsors:
- Power Division
- Advanced Energy Systems Division
- Solar Energy Division
- Nuclear Engineering Division
ISBN:
978-0-7918-5761-8
PROCEEDINGS PAPER
Characterization of Crack Tip Damage Zone Formation on Alloy 625 During Fatigue Crack Growth at 750°C by Transmission EBSD Method
Yuji Ozawa,
Yuji Ozawa
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Search for other works by this author on:
Tatsuya Ishikawa,
Tatsuya Ishikawa
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Search for other works by this author on:
Yoichi Takeda
Yoichi Takeda
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Search for other works by this author on:
Yuji Ozawa
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Tatsuya Ishikawa
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Yoichi Takeda
Tohoku University, Fracture and Reliability Research Institute, Sendai, Japan
Paper No:
POWER-ICOPE2017-3458, V002T08A018; 7 pages
Published Online:
September 5, 2017
Citation
Ozawa, Y, Ishikawa, T, & Takeda, Y. "Characterization of Crack Tip Damage Zone Formation on Alloy 625 During Fatigue Crack Growth at 750°C by Transmission EBSD Method." Proceedings of the ASME 2017 Power Conference Joint With ICOPE-17 collocated with the ASME 2017 11th International Conference on Energy Sustainability, the ASME 2017 15th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2017 Nuclear Forum. Charlotte, North Carolina, USA. June 26–30, 2017. V002T08A018. ASME. https://doi.org/10.1115/POWER-ICOPE2017-3458
Download citation file:
19
Views
Related Proceedings Papers
Related Articles
A Nonlinear Thermomechanical Model of Spinel Ceramics Applied to Aluminum Oxynitride (AlON)
J. Appl. Mech (January,2011)
Fatigue Crack Growth Behavior of Alloy 800H at Elevated Temperature
J. Eng. Mater. Technol (July,1991)
Deformation Modes in Stainless Steel During Laser Shock Peening
J. Manuf. Sci. Eng (October,2009)
Related Chapters
The Relation between Cold-Work-Induced Microstructural Evolution and the Postannealing Grain Structures in Zircaloy-4
Zirconium in the Nuclear Industry: 20th International Symposium
Characterization and Modeling of the Influence of Initial Microstructure on Recrystallization of Zircaloy‐4 during Hot Forming
Zirconium in the Nuclear Industry: 20th International Symposium
Use of Large Standoff Magnetometry for Geohazard Pipeline Integrity Investigations
Pipeline Integrity Management Under Geohazard Conditions (PIMG)