Hydrogen Effect on the Deformation Behavior of Austenitic Stainless Steels Investigated by Nanoindentation

2017 ◽  
Author(s):  
Lin Zhang ◽  
Yuanjian Hong ◽  
Jinyang Zheng ◽  
Bai An ◽  
Chengshuang Zhou
Keyword(s):  
Plastic Deformation ◽  
Stainless Steels ◽  
Deformation Behavior ◽  
Austenitic Stainless Steels ◽  
Gaseous Hydrogen ◽  
Hydrogen Effect ◽  
Full Understanding ◽  
Stiffness Measurement ◽  
Initial Stage ◽  
Continuous Stiffness Measurement

A full understanding of hydrogen effect on deformation is important to reveal the mechanism of hydrogen embrittlement. The effects of thermal gaseous hydrogen charging on 304 and 310S austenitic stainless steels have been examined by using nanoindentation. It is first found by using nanoindentation continuous stiffness measurement that hydrogen decreases the elastic modulus and increases the hardness in the initial stage of plastic deformation, while the hydrogen effect becomes weaker and remains nearly constant with further plastic deformation. Hydrogen increases the creep displacement in 310S steel, which indicates that hydrogen facilitates ambient creep. α′ martensite restrains the nanoindentation creep and hydrogen has little effect on the creep induced by α′ martensite.

Reduction in Fretting Fatigue Strength of Austenitic Stainless Steels due to Internal Hydrogen

2014 ◽  
Vol 891-892 ◽  
pp. 891-896 ◽  
Author(s):  
Ryosuke Komoda ◽  
Naoto Yoshigai ◽  
Masanobu Kubota ◽  
Jader Furtado
Keyword(s):  
Plastic Deformation ◽  
Fatigue Strength ◽  
Crack Initiation ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Fretting Fatigue ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Internal Hydrogen ◽  
Major Factors

Fretting fatigue is one of the major factors in the design of hydrogen equipment. The effect of internal hydrogen on the fretting fatigue strength of austenitic stainless steels was studied. The internal hydrogen reduced the fretting fatigue strength. The reduction in the fretting fatigue strength became more significant with an increase in the hydrogen content. The reason for this reduction is that the internal hydrogen assisted the crack initiation. When the fretting fatigue test of the hydrogen-charged material was carried out in hydrogen gas, the fretting fatigue strength was the lowest. Internal hydrogen and gaseous hydrogen synergistically induced the reduction in the fretting fatigue strength of the austenitic stainless steels. In the gaseous hydrogen, fretting creates adhesion between contacting surfaces where severe plastic deformation occurs. The internal hydrogen is activated at the adhered part by the plastic deformation which results in further reduction of the crack initiation limit.

Effect of Gaseous Hydrogen Charging on Nanohardness of Austenitic Stainless Steels

2016 ◽  
Author(s):  
Lin Zhang ◽  
Bai An ◽  
Takashi Iijima ◽  
Chris San Marchi
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Gaseous Hydrogen ◽  
Hydrogen Effect ◽  
Force Microscopy ◽  
Strain Induced Martensite ◽  
Deformation Interaction ◽  
Metastable Austenitic Stainless Steel

Understanding of hydrogen effect on local mechanical properties of metals is important for understanding hydrogen embrittlement mechanisms. The effect of thermal gaseous hydrogen precharging on the nanomechanics of SUS310S and SUS304 austenitic stainless steels has been investigated using a combination of nanoindentation and atomic force microscopy (AFM). It is observed that hydrogen precharging decreases the first excursion load in load versus displacement curves and enhances the slip steps around indentations for both the materials, which experimentally support the hydrogen-enhanced localized plasticity (HELP) mechanism. The nanohardness in SUS310S stable austenitic stainless steel is increased by hydrogen precharging while that in SUS304 metastable austenitic stainless steel is decreased by hydrogen precharging. The hydrogen-induced hardening in SUS310S and softening in SUS304 are discussed in terms of the hydrogen/deformation interaction and the effect of hydrogen on strain-induced martensite transformation.

scholarly journals Hydrogen-Assisted Fracture of Type 316L Tubing and Orbital Welds

2013 ◽  
Author(s):  
C. San Marchi ◽  
L. A. Hughes ◽  
B. P. Somerday ◽  
X. Tang
Keyword(s):  
Stainless Steels ◽  
Base Material ◽  
Austenitic Stainless Steels ◽  
Gaseous Hydrogen ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Type 316L ◽  
316L Austenitic Stainless Steel ◽  
Outside Diameter ◽  
Assisted Fracture

Austenitic stainless steels have been extensively tested in hydrogen environments. These studies have identified the relative effects of numerous materials and environmental variables on hydrogen-assisted fracture. While there is concern that welds are more sensitive to environmental effects than the non-welded base material, in general, there have been relatively few studies of the effects of gaseous hydrogen on the fracture and fatigue resistance of welded microstructures. The majority of published studies have considered welds with geometries significantly different from the welds produced in assembling pressure manifolds. In this study, conventional, uniaxial tensile testing was used to characterize tubing of type 316L austenitic stainless steel with an outside diameter of 6.35 mm. Additionally, orbital tube welds were produced and tested to compare to the non-welded tubing. The effects of internal hydrogen were studied after saturating the tubes and orbital welds with hydrogen by exposure to high-pressure gaseous hydrogen at elevated temperature. The effects of hydrogen on the ductility of the tubing and the orbital tube welds were found to be similar to the effects observed in previous studies of type 316L austenitic stainless steels.

scholarly journals Plastic Deformation Influence on Intrinsic Magnetic Field of Austenitic Biomaterials

2016 ◽  
Vol 67 (6) ◽  
pp. 407-413
Author(s):  
Milan Smetana ◽  
Klára Čápová ◽  
Vladimír Chudáčik ◽  
Peter Palček ◽  
Monika Oravcová
Keyword(s):  
Magnetic Field ◽  
Plastic Deformation ◽  
Austenitic Steel ◽  
Medical Practice ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Intrinsic Magnetic Field ◽  
Fluxgate Sensor ◽  
Non Destructive Evaluation ◽  
Non Destructive

Abstract This article deals with non-destructive evaluation of austenitic stainless steels, which are used as the biomaterials in medical practice. Intrinsic magnetic field is investigated using the fluxgate sensor, after the applied plastic deformation. The three austenitic steel types are studied under the same conditions, while several values of the deformation are applied, respectively. The obtained results are presented and discussed in the paper.

scholarly journals Effect of Hydrogen on the Deformation Behavior and Localization of Plastic Deformation of the Ultrafine-Grained Zr–1Nb Alloy

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 592
Author(s):  
Ekaterina Stepanova ◽  
Galina Grabovetskaya ◽  
Maxim Syrtanov ◽  
Ivan Mishin
Keyword(s):  
Plastic Deformation ◽  
Deformation Behavior ◽  
Macro Level ◽  
Hydrogen Effect ◽  
Ultrafine Grained Structure ◽  
Fine Grained ◽  
Element Size ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Localization Of Plastic Deformation

In this paper, comparison studies of the hydrogen effect on the structural and phase state, deformation behavior, and mechanical properties of the fine- (average grain size 4 µm) and ultrafine-grained (average element size 0.3 and 0.4 µm) Zr–1wt.%Nb (hereinafter Zr–1Nb) alloy under tension at temperatures in the range of 293–873 K were conducted. The formation of an ultrafine-grained structure is established to increase the strength characteristics of the Zr–1Nb alloy by a factor of 1.5–2 with a simultaneous reduction of its resistance to the localization of plastic deformation at the macro level and the value of deformation to failure. The presence of hydrogen in the Zr–1Nb alloy in the form of a solid solution and hydride precipitates increases its resistance to the localization of plastic deformation at the macro level if the alloy has an ultrafine-grained structure and decreases if the structure of the alloy is fine-grained. In the studied temperature range, the Zr–1Nb alloy in the ultrafine-grained state has a higher resistance to hydrogen embrittlement than the alloy in the fine-grained state.

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