Influence of activation energy and sensitivity to hydrogen embrittlement on fatigue strength degradation by irreversible hydrogen in high-strength steels

2010 ◽  
Vol 34 (5) ◽  
pp. 363-373 ◽  
Author(s):  
M. NAKATANI ◽  
K. MINOSHIMA
Keyword(s):  
Activation Energy ◽  
Fatigue Strength ◽  
Hydrogen Embrittlement ◽  
High Strength Steels ◽  
High Strength ◽  
Strength Degradation

Fatigue Strength Degradation by Irreversible Hydrogen in Cold Drawn Eutectoid Steels

2011 ◽  
Vol 462-463 ◽  
pp. 188-193
Author(s):  
Masanori Nakatani ◽  
Kohji Minoshima
Keyword(s):  
Activation Energy ◽  
Fatigue Strength ◽  
Hydrogen Embrittlement ◽  
High Sensitivity ◽  
Fatigue Tests ◽  
Strength Degradation ◽  
Trap Site ◽  
High Activation ◽  
High Activation Energy ◽  
Higher Sensitivity

The fatigue tests were conducted for cold-drawn eutectoid steels having different activation energies and microstructures to investigate the mechanism of fatigue strength degradation by irreversible hydrogen. The fatigue strength of a sample with low activation energy was decreased by irreversible hydrogen, whereas the fatigue strength of a sample with high activation energy was not. When the activation energy for irreversible hydrogen becomes small, the desorption of irreversible hydrogen from its trap site is easily induced by cyclic loading, which results in a decrease in fatigue strength. When a sample having high activation energy was annealed at 473 K, the fatigue strength was decreased by irreversible hydrogen although the activation energy barely changed. This is because the precipitation of fine carbides due to annealing causes higher sensitivity to hydrogen embrittlement. High sensitivity to hydrogen embrittlement was concluded to induce the fatigue strength degradation by irreversible hydrogen. Therefore, the degradation of fatigue strength by irreversible hydrogen depends on the activation energy and sensitivity to hydrogen embrittlement.

scholarly journals Quantitative tests revealing hydrogen enhanced dislocation motion in α-iron

2021 ◽  
Author(s):  
Long-Chao Huang ◽  
Dengke Chen ◽  
De-Gang Xie ◽  
Suzhi Li ◽  
Ting Zhu ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
High Strength Steels ◽  
High Strength ◽  
Dislocation Motion ◽  
Atomistic Simulations ◽  
Vacuum Degassing ◽  
Nucleation Barrier ◽  
Free Behavior ◽  
Individual Dislocation ◽  
Energy Transportation

Abstract Hydrogen embrittlement jeopardizes the use of high-strength steels as critical load-bearing components in energy, transportation, and infrastructure applications. However, our understanding of hydrogen embrittlement mechanism is still obstructed by the uncertain knowledge of how hydrogen affects dislocation motion, due to the lack of quantitative experimental evidence. Here, by studying the well-controlled, cyclic, bow-out movements of individual screw dislocations, the key to plastic deformation in α-iron, we find that the critical stress for initiating dislocation motion in a 2 Pa electron-beam-excited H2 atmosphere is 27~43% lower than that under vacuum conditions, proving that hydrogen lubricates screw dislocation motion. Moreover, we find that aside from vacuum degassing, dislocation motion facilitates the de-trapping of hydrogen, allowing the dislocation to regain its hydrogen-free behavior. Atomistic simulations reveal that the observed hydrogen-enhanced dislocation motion arises from the hydrogen-reduced kink nucleation barrier. These findings at individual dislocation level can help hydrogen embrittlement modelling in steels.

Role of elongated MnS inclusions in hydrogen embrittlement of high-strength steels

Metal Science ◽  
1982 ◽  
Vol 16 (12) ◽  
pp. 543-554 ◽  
Author(s):  
T. V. Venkatasubramanian ◽  
T. J. Baker
Keyword(s):  
Hydrogen Embrittlement ◽  
High Strength Steels ◽  
High Strength
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