scholarly journals Scanning Kelvin Probe Investigation of High-Strength Steel Surface after Impact of Hydrogen and Tensile Strain

2020 ◽  
Vol 1 (1) ◽  
pp. 187-197 ◽  
Author(s):  
Andrei Nazarov ◽  
Flavien Vucko ◽  
Dominique Thierry
Keyword(s):  
Tensile Deformation ◽  
Electron Work Function ◽  
High Strength Steels ◽  
High Strength ◽  
Potential Drop ◽  
Hydrogen Uptake ◽  
Surface Oxide ◽  
Kelvin Probe ◽  
Scanning Kelvin Probe ◽  
Cracking Mechanisms

Hydrogen in combination with mechanical stress can lead to rapid degradation of high-strength steels through environmentally assisted cracking mechanisms. The scanning Kelvin probe (SKP) was applied to automotive martensitic steel grade MS1500 in order to detect local reactivity of the surface after hydrogen uptake and tensile deformation. Hydrogen and stress distribution in microstructures can be characterized by SKP indirectly measuring the potential drop in the surface oxide. Thus, the links between electron work function, oxide condition, and subsurface accumulation of hydrogen and stress have to be investigated. It was shown that plastic strain can mechanically break down the oxide film creating active (low potential) locations. Hydrogen effusion from the steel bulk, after cathodic charging in aqueous electrolyte, reduced the surface oxide and also decreased potential. It was shown that surface re-oxidation was delayed as a function of the current density and duration of cathodic hydrogen pre-charging. Thus, potential evolution during exposure in air can characterize the relative amount of subsurface hydrogen. SKP mapping of martensitic microstructure with locally developed residual stress and accumulated hydrogen displayed the lowest potential.

Techniques for investigation of hydrogen embrittlement of advanced high strength steels

2018 ◽  
Vol 36 (5) ◽  
pp. 413-434 ◽  
Author(s):  
Darya Rudomilova ◽  
Tomáš Prošek ◽  
Gerald Luckeneder
Keyword(s):  
Hydrogen Embrittlement ◽  
Secondary Ion Mass Spectrometry ◽  
High Strength Steels ◽  
Thermal Desorption Spectroscopy ◽  
High Strength ◽  
Atmospheric Conditions ◽  
Kelvin Probe ◽  
Advanced High Strength Steels ◽  
Scanning Kelvin Probe ◽  
Atmospheric Exposure

AbstractProduction volumes of advanced high strength steels (AHSS) are growing rapidly due to material and energy savings they provide in a number of application areas. In order to use their potential fully, it is necessary to minimize any danger of unexpected failures caused by hydrogen embrittlement. It is possible only if deeper understanding of underlying mechanisms is obtained through further research. Besides description of main grades of AHSS and mechanisms of HE, this paper reviews available tools for determination of hydrogen content and susceptibility to HE focusing on atmospheric conditions. Techniques such as slow strain rate testing, constant load testing, electrochemical permeation technique, scanning Kelvin probe and scanning Kelvin probe force microscopy have already been used to study the effect of hydrogen entered under atmospheric exposure conditions. Nanoindentation, hydrogen microprint technique, thermal desorption spectroscopy, Ag decoration or secondary ion mass spectrometry can be also conducted after atmospheric exposure.

scholarly journals The effect of Nb on the high strain rate hydrogen embrittlement of Q&P steel

2021 ◽  
Vol 250 ◽  
pp. 03007
Author(s):  
Florian Vercruysse ◽  
Lisa Claeys ◽  
Tom Depover ◽  
Kim Verbeken ◽  
Patricia Verleysen ◽  
...  
Keyword(s):  
Strain Rate ◽  
High Strength Steels ◽  
Thermal Desorption Spectroscopy ◽  
High Strength ◽  
Hydrogen Uptake ◽  
High Hydrogen ◽  
Damage Initiation ◽  
Advanced High Strength Steels ◽  
Dynamic Tensile Loading ◽  
Carbon Martensite

Quenching and Partitioning (Q&P) steels are, due to their excellent combination of strength and ductility, seen as good candidates for the third generation advanced high strength steels (AHSS). Although the TRIP effect is beneficial for the overall mechanical behaviour of these steels it potentially can have detrimental effects when strained in a hydrogenenriched environment. The solubility of hydrogen is high in austenite but low in high carbon martensite. Martensite is even in the absence of hydrogen already a possible damage initiation spot. The effect of hydrogen under static and dynamic tensile loading was evaluated in a Q&P and a Nb micro-alloyed Q&P steel. Experiments were carried out under a strain rate ranging from 0.03 s-1 till 500 s-1 and correlated with the hydrogen uptake characterised via thermal desorption spectroscopy (TDS). The presence of Nb resulted in a 25% increase in the hydrogen uptake capacity. A higher susceptibility to hydrogen was observed in the Nb steel partially due to the high hydrogen fraction, but also because of the larger fraction of low stability austenite. However, when tested under dynamic conditions the hydrogen susceptibility is minor and even improved in the micro-alloyed Q&P steel compared to the standard Q&P steel.

Hydrogen Entry Into Steel Under Corrosion Products

CORROSION ◽  
10.5006/3675 ◽  
2021 ◽  
Author(s):  
Darya Rudomilova ◽  
Tomáš Prošek ◽  
Mats Strom
Keyword(s):  
Atomic Hydrogen ◽  
High Strength Steels ◽  
High Strength ◽  
Corrosion Products ◽  
Homogeneous Layer ◽  
Hydrogen Ions ◽  
Atmospheric Conditions ◽  
Kelvin Probe ◽  
Rust Layer ◽  
Corrosion Pits

Hydrogen entry into high strength steel after local sodium chloride pre-deposition and during exposure to humid air was studied using scanning Kelvin probe. Two regions with different pH, potential and red rust composition were formed on the corroding side of the specimen. Hydrogen permeating through the specimen was detected over the region with the net cathodic character, which was linked to oxygen reduction taking place on top and within the red rust layer whereas anodic dissolution progressed inside the rust covered pits creating conditions favourable for formation of hydrogen ions. No measurable hydrogen entry was detected in the area covered with an apparently homogeneous layer of corrosion products and corroding uniformly. The finding that corrosion pits were the main source of atomic hydrogen implies that the susceptibility of high strength steels to pitting corrosion is an important parameter for evaluation of the risk of hydrogen embrittlement under atmospheric conditions.

Hydrogen detection in high strength dual phase steel using scanning Kelvin probe technique and XPS analyses

2021 ◽  
pp. 110072
Author(s):  
Flavien Vucko ◽  
Shinji Ootsuka ◽  
Stéphane Rioual ◽  
Erwan Diler ◽  
Andrej Nazarov ◽  
...  
Keyword(s):  
Dual Phase Steel ◽  
High Strength ◽  
Dual Phase ◽  
Kelvin Probe ◽  
Hydrogen Detection ◽  
Probe Technique ◽  
Scanning Kelvin Probe

Optimization of Metallographic Sample Preparation for AFM/SKPFM Based Phase Distinction of Complex and Dual Phase High Strength Steels

2021 ◽  
Vol 58 (6) ◽  
pp. 308-331
Author(s):  
I. Traxler ◽  
G. Schimo-Aichhorn ◽  
A. Muhr ◽  
C. Commenda ◽  
A. Jerrar ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Hydrogen Permeability ◽  
High Strength Steels ◽  
High Strength ◽  
Dual Phase ◽  
Kelvin Probe ◽  
Preparation Methods ◽  
Force Microscopy ◽  
Steel Grades ◽  
The Individual

Abstract For the comprehensive investigation of advanced high strength steel grades, like complex and dual phase steels, Atomic Force Microscopy (AFM) and Scanning Kelvin Probe Force Microscopy (SKPFM) have proven to be useful tools, especially for analysis of hydrogen permeability of the individual steel phases. However, for these studies a preparation route, exposing the microstructure of the steel, is necessary. Various sample preparation methods were examined, focusing on electropolishing and sputtering, and the selected route was optimized to guarantee reproducibility and stability of the prepared surface. Electropolishing was shown to be highly efficient to selectively reveal the individual steel phases without introducing strong topographical features disturbing the AFM measurements. A subsequent sputtering step was introduced to improve the stability and preservability of the surface up to several months. Finally, distinction of the steel phases via AFM/SKPFM, was complemented and compared with results from EBSD and XRD.

Evaluation on Adhesion Strength of Laser Induction Hybrid Rapid Cladding Cu-Fe-Based Coatings Using Scanning Kelvin Probe

2015 ◽  
Vol 1096 ◽  
pp. 103-106
Author(s):  
Xiao Qin Dai ◽  
Sheng Feng Zhou ◽  
Zheng Xiong
Keyword(s):  
Solid Solution ◽  
Tensile Strength ◽  
Work Function ◽  
Adhesion Strength ◽  
Electron Work Function ◽  
Nondestructive Method ◽  
Kelvin Probe ◽  
Scanning Kelvin Probe ◽  
Logarithmic Relationship ◽  
Laser Induction

It is very important to effectively evaluate the adhesion strength of coating. A nondestructive method to evaluate the adhesion strength of laser induction hybrid rapid cladding Cu-Fe-based coatings was investigated. The electron work function of coatings was measured by scanning Kelvin probe. It was demonstrated that the Fe-rich particles and solid solution of Fe can increase the EWF and the tensile strength. A logarithmic relationship between the ratio of EWF to dilution and the adhesion strength was established.

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