SYMPOSIA PAPER Published: 01 January 1997
STP16242S

Effect of Absorbed Hydrogen on the Microstructure in the Vicinity of Near-Threshold Fatigue Cracks in Low-Alloy Steel

Source

The influence of a dry hydrogen environment on near-threshold crack growth propagation rates of fatigue cracks in a low-alloy spheroidized steel was investigated. for separation of environmental and mechanically induced effects, fatigue tests in an ultra-high vacuum (UHV) environment were taken as reference. On a macroscopic scale, we found a significant acceleration of the propagation rates of cracks exposed to a dry hydrogen atmosphere compared to tests in an inert environment. The electron-microscopic characterization of the microstructure in the vicinity of cracks revealed that the acceleration of fatigue propagation by hydrogen can be rationalized by a hydrogen-involved fatigue damage mechanism. Furthermore, it was concluded that hydrogen enhances the dislocation mobility. This effect aids in the formation of dislocation cellular structure in the cyclic plastic zone. The mode of fracture itself is ductile transgranular and appears to be unchanged by absorption of hydrogen at the crack tip.

Author Information

Heldt, J
Institute for Materials Sciences, Chair for Corrosion and Surface Protection, University of Erlangen-Nuremberg, Germany
Kaesche, H
Institute for Materials Sciences, Chair for Corrosion and Surface Protection, University of Erlangen-Nuremberg, Germany
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E08
Pages: 338–351
DOI: 10.1520/STP16242S
ISBN-EB: 978-0-8031-5355-4
ISBN-13: 978-0-8031-2412-7