scholarly journals Hydrogen and deuterium charging of site-specific specimen for atom probe tomography

2021 ◽  
Vol 1 ◽  
pp. 122
Author(s):  
Heena Khanchandani ◽  
Se-Ho Kim ◽  
Rama Srinivas Varanasi ◽  
TS Prithiv ◽  
Leigh T. Stephenson ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Atom Probe Tomography ◽  
High Strength Steels ◽  
High Strength ◽  
Atom Probe ◽  
Structural Defects ◽  
Future Research ◽  
Site Specific ◽  
Modelling Studies ◽  
Underlying Mechanisms

Hydrogen embrittlement can cause a dramatic deterioration of the mechanical properties of high-strength metallic materials. Despite decades of experimental and modelling studies, the exact underlying mechanisms behind hydrogen embrittlement remain elusive. To unlock understanding of the mechanism and thereby help mitigate the influence of hydrogen and the associated embrittlement, it is essential to examine the interactions of hydrogen with structural defects such as grain boundaries, dislocations and stacking faults. Atom probe tomography (APT) can, in principle, analyse hydrogen located specifically at such microstructural features but faces strong challenges when it comes to charging specimens with hydrogen or deuterium. Here, we describe three different workflows enabling hydrogen/deuterium charging of site-specific APT specimens: namely cathodic, plasma and gas charging. We discuss in detail the caveats of the different approaches in order to help future research efforts and facilitate further studies of hydrogen in metals. Our study demonstrates successful cathodic and gas charging, with the latter being more promising for the analysis of the high-strength steels at the core of our work.

scholarly journals Understanding the Behavior of Advanced High-Strength Steels Using Atom Probe Tomography

2011 ◽  
Vol 43 (11) ◽  
pp. 3958-3971 ◽  
Author(s):  
Elena Pereloma ◽  
Hossein Beladi ◽  
Laichang Zhang ◽  
Ilana Timokhina
Keyword(s):  
Atom Probe Tomography ◽  
High Strength Steels ◽  
High Strength ◽  
Atom Probe ◽  
Advanced High Strength Steels

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

Automated Sample Depth Targeting with Low kV Cleaning by Focused Ion Beam Microscopy for Atom Probe Tomography

2020 ◽  
Author(s):  
Woo Jun Kwon ◽  
Jisu Ryu ◽  
Christopher H. Kang ◽  
Michael B. Schmidt ◽  
Nicholas Croy
Keyword(s):  
Sample Preparation ◽  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Region Of Interest ◽  
Atom Probe ◽  
Sample Volume ◽  
Cleaning Process ◽  
Site Specific ◽  
Sample Depth

Abstract Focused ion beam (FIB) microscopy is an essential technique for the site-specific sample preparation of atom probe tomography (APT). The site specific APT and automated APT sample preparation by FIB have allowed increased APT sample volume. In the workflow of APT sampling, it is very critical to control depth of the sample where exact region of interest (ROI) for accurate APT analysis. Very precise depth control is required at low kV cleaning process in order to remove the damaged layer by previous high kV FIB process steps. We found low kV cleaning process with 5 kV and followed by 2kV beam conditions delivers better control to reached exact ROI on Z direction. This understanding is key to make APT sample with fully automated fashion.

scholarly journals A method for site-specific and cryogenic specimen fabrication of liquid/solid interfaces for atom probe tomography

2018 ◽  
Vol 194 ◽  
pp. 89-99 ◽  
Author(s):  
D.K. Schreiber ◽  
D.E. Perea ◽  
J.V. Ryan ◽  
J.E. Evans ◽  
J.D. Vienna
Keyword(s):  
Atom Probe Tomography ◽  
Atom Probe ◽  
Site Specific
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