Hydrogen effect on fatigue performance of commercially pure BCC iron has been studied with a combination of various electron microscopy techniques. The fatigue crack growth (FCG) in gaseous hydrogen was found to consist of two regimes corresponding to a slightly accelerated regime at relatively low stress intensity factor range, ΔK, (Stage I) and the highly accelerated regime at relatively high ΔK (Stage II). These regimes were manifested by the intergranular and quasicleavage types of fractures respectively. Scanning electron microscopy (SEM) observations demonstrated an increase in plastic deformation around the crack wake in the Stage I, but considerably lower amount of plasticity around the crack path in the Stage II. Transmission electron microscopy (TEM) results identified dislocation cell structure immediately beneath the fracture surface of the Stage I sample, and dislocation tangles in the Stage II sample corresponding to fracture at high and low plastic strain amplitudes respectively.
Hydrogen-Assisted Fatigue Crack Propagation in a Commercially Pure BCC Iron
- Views Icon Views
- Share Icon Share
- Search Site
Birenis, D, Ogawa, Y, Matsunaga, H, Takakuwa, O, Yamabe, J, Prytz, Ø, & Thøgersen, A. "Hydrogen-Assisted Fatigue Crack Propagation in a Commercially Pure BCC Iron." Proceedings of the ASME 2018 Pressure Vessels and Piping Conference. Volume 6B: Materials and Fabrication. Prague, Czech Republic. July 15–20, 2018. V06BT06A039. ASME. https://doi.org/10.1115/PVP2018-84783
Download citation file: