Journal ArticleDOI
Hydrogen enhanced crack growth in 18 Ni maraging steels
S. J. Hudak,Robert P. Wei +1 more
TLDR
In this article, the kinetics of sustained load subcritical crack growth for 18 Ni maraging steels in high purity hydrogen are examined using crack-tip stress intensity,K, as a measure of crack driving force.Abstract:
The kinetics of sustained-load subcritical crack growth for 18 Ni maraging steels in high purity hydrogen are examined using crack-tip stress intensity,K, as a measure of crack driving force. Crack growth rate as a function of stress intensity exhibited a clearly definedK-independent stage (Stage II). Crack growth rates in an 18 Ni (250) maraging steel are examined for temperatures from -60°C to 100°C. A critical temperature was observed above which crack growth rates became diminishingly small. At lower temperatures the activation energy for Stage II crack growth was found to be 16.7 ± 3.3 kJ/mole. Temperature and hydrogen partial pressure are shown to interact in a complex manner to determine the apparentK
th
and the crack growth behavior. Comparison of results on ‘250’ and ‘300’ grades of 18 Ni maraging steel indicate a significant influence of alloy composition and/or strength level on the crack growth behavior. These phenomenological observations are discussed in terms of possible underlying controlling processes.read more
Citations
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Journal ArticleDOI
Intergranular fracture in 4340-type steels: Effects of impurities and hydrogen
TL;DR: In this paper, a study has been made of the conditions which lead to intergranular brittle fracture in 4340-type steels at an ultra high yield strength level (200 ksi, 380 MPa) in both an ambi-ent environment and gaseous hydrogen.
Intergranular fracture in 4340-type steels: effects of impurities and hydrogen. Final report, 8 December 1975--7 December 1976
TL;DR: In this paper, a study of the conditions which lead to intergranular brittle fracture in 4340-type steels at an ultra-high yield strength level (200 ksi, 1380 MPa) in both an ambient environment and gaseous hydrogen was made.
Journal ArticleDOI
Near-threshold fatigue-crack propagation in steels
TL;DR: In this article, the effects of various mechanical, microstructural, and environmental factors which influence fatigue-crack propagation in steels at growth rates less than 10-6 mm/cycle, where the alternating stress intensity approaches the so-called threshold stress intensity ∆K0 below which crack growth cannot be experimentally detected.
Journal ArticleDOI
Gaseous hydrogen embrittlement of high strength steels
TL;DR: In this article, the kinetics of sustained-load subcritical crack growth in hydrogen were determined for 18Ni(200) and 18Ni (250) maraging steels over a range of hydrogen pressures and temperatures.
Journal ArticleDOI
Fracture Mechanics and Surface Chemistry Studies of Subcritical Crack Growth in AISI 4340 Steel.
TL;DR: In this article, the authors investigated the role of hydrogen in the embrittling process of crack growth in high strength steels, and found that hydrogen is the hydrogen species responsible for embrittlement.
References
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Journal ArticleDOI
A new model for hydrogen-assisted cracking (hydrogen “embrittlement”)
TL;DR: A new model for hydrogen-assisted cracking is presented in this article, which explains the observations of decreasing microscopic plasticity and changes of fracture modes with decreasing stress intensities at crack tips during stress-corrosion cracking and HAC of quenched-and tempered steels.
Journal ArticleDOI
Hydrogen embrittlement of metals
TL;DR: The deleterious effects of hydrogen on the tensile properties of metals are caused by the association and movement of hydrogen with dislocations as discussed by the authors, and hydrogen-dislocation interactions modify plastic deformation processes by stabilizing microcracks, by changing the work hardening rate, and by solid solution hardening.
Journal ArticleDOI
The Thermodynamics of Stressed Solids
TL;DR: In this article, the existence of a chemical potential of a mobile component everywhere within a solid within a generalized stress system is demonstrated, as well as also the presence of an immobile component of a stressed body at appropriate interfaces.
Journal ArticleDOI
Effect of Width and Length on Stress Intensity Factors of Internally Cracked Plates Under Various Boundary Conditions
TL;DR: In this article, the analysis of stress intensity factors of a strip with a longitudinal crack subject to tension and bending along its edges, and the tension of rectangular plates with a central crack are considered.
Journal ArticleDOI
Delayed Fracture of Metals under Static Load
N. J. Petch,P. Stables +1 more
TL;DR: In the case of glass fracture, Orowan et al. as discussed by the authors explained it as gas adsorption on the Griffith crack surface and discussed a similar theory with Gurney and Pearson.