M 4 C 3 precipitation in Fe–C–Mo–V steels and relationship to hydrogen trapping

2006 ◽  
Vol 462 (2072) ◽  
pp. 2315-2330 ◽  
Author(s):  
S Yamasaki ◽  
H.K.D.H Bhadeshia
Keyword(s):  
Kinetic Theory ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Hydrogen Atoms ◽  
Elastic Interactions ◽  
Dissolved Hydrogen ◽  
Coherency Strains ◽  
Carbide Particles

Strong steels suffer from embrittlement due to dissolved hydrogen, a phenomenon which can be mitigated by trapping the hydrogen at carbide particles, where it is rendered benign. The precipitation and coarsening of plate-like M 4 C 3 carbides, during the tempering of quaternary Fe–C–Mo–V martensitic steels, has been characterized both experimentally and by developing appropriate kinetic theory. The trapping capacity is found to peak when the carbides are about 10 nm in length, indicating a role of coherency strains in trapping hydrogen atoms via elastic interactions. This suggests a method for developing alloys which are better able to resist the detrimental effects of hydrogen.

Role of Mo/V carbides in hydrogen embrittlement of tempered martensitic steel

2015 ◽  
Vol 33 (6) ◽  
pp. 433-441 ◽  
Author(s):  
Junmo Lee ◽  
Taekyung Lee ◽  
Young Jin Kwon ◽  
Dong-Jun Mun ◽  
Jang-Yong Yoo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Hydrogen Embrittlement ◽  
Beneficial Effect ◽  
Mechanical Performance ◽  
Martensitic Steel ◽  
Carbide Precipitation ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Cr Addition

AbstractThe vulnerability of tempered martensitic steel to hydrogen embrittlement (HE) has attracted attention from a number of researchers. Although utilizing carbide precipitation is one of effective methods to improve HE resistance, few studies have focused on the effects of carbide characteristics, such as the chemical composition and morphology of carbide. This work clarifies the role of Mo carbide and V carbide in the HE behavior of tempered martensitic steels with four steels whose chemical composition was carefully controlled. The beneficial effect of carbides is discussed in terms of hydrogen trapping and fracture mode. The low amount of trapped hydrogen and undissolved carbide led to excellent HE resistance of Mo carbides compared to V carbides. In addition, the superior mechanical performance of Cr-Mo steel was also interpreted by the effect of Cr addition as well as Mo carbides.

Study of the Role of Small Additions of Zr in the CVD- FBR Aluminization Process

2009 ◽  
Vol 289-292 ◽  
pp. 293-300
Author(s):  
L. Sánchez ◽  
F.J. Bolívar ◽  
M.P. Hierro ◽  
F.J. Pérez
Keyword(s):  
Fluidized Bed ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Fluidized Bed Reactor ◽  
Iron Aluminide ◽  
Martensitic Steels ◽  
Aluminide Coatings ◽  
Deposition Parameters ◽  
Zirconium Powder

In this work, iron aluminide coatings were developed by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic-martensitic steels. Small additions of zirconium powder were introduced in the fluidized bed; as a consequence, the obtained coatings are thicker than that without zirconium additions. When Zr powders are added in the fluidized bed, the deposition atmosphere drastically changes, leading to increase the deposition rate. Thermodynamic calculations were carried out to simulate the modifications in the CVD atmosphere in the Al/Zr deposition system in comparison to the single aluminization. In order to optimize the conditions of the deposition, parameters such as temperature and concentration of zirconium introduced into the bed were evaluated and compared with the results obtained for the single aluminum deposition.

The reaction of hydrogen atoms with 1-butanethiol and thiolane the role of chemically activated 1-butanethiol

1978 ◽  
Vol 10 (10) ◽  
pp. 1043-1054 ◽  
Author(s):  
Osamu Horie ◽  
Junya Nishino ◽  
Akira Amano
Keyword(s):  
Hydrogen Atoms

Hydrogen Transport in 34CrMo4 Martensitic Steel: Influence of Microstructural Defects on H Diffusion

2012 ◽  
Vol 323-325 ◽  
pp. 485-490 ◽  
Author(s):  
L. Moli-Sanchez ◽  
F. Martin ◽  
E. Leunis ◽  
J. Chêne ◽  
M. Wery
Keyword(s):  
Diffusion Coefficient ◽  
Room Temperature ◽  
Martensitic Steel ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Hydrogen Diffusivity ◽  
Apparent Diffusion ◽  
Quenched Steel ◽  
Set Up ◽  
Permeation Test

The electrochemical permeation technique was used to evaluate the effect of the microstructure on hydrogen diffusivity and hydrogen trapping at room temperature in martensitic steels. A detailed study of the electrochemical permeation technique was first performed in order to identify the boundary conditions of a permeation test in the selected experimental set-up. The validity of the apparent diffusion coefficient derived from this test is also discussed. A 34CrMo4 quenched steel has been selected and designed at three tempering temperatures (200°C, 540°C and 680°C) in order to obtain three different microstructures. According to permeation measurements, H diffusion strongly depends on the microstructure. The material tempered at 540°C exhibits the smallest diffusion coefficient and the largest fraction of reversible traps at room temperature.

The vacuum ultraviolet photolysis of hydrogen chloride. The role of the hot hydrogen atoms

1981 ◽  
Vol 55 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
A. Jówko ◽  
S. U. Pavlova ◽  
H. Baj ◽  
B. G. Dzantiev ◽  
M. Foryś
Keyword(s):  
Hydrogen Chloride ◽  
Vacuum Ultraviolet ◽  
Hydrogen Atoms ◽  
Ultraviolet Photolysis

scholarly journals Density functional theory study of the role of benzylic hydrogen atoms in the antioxidant properties of lignans

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Quan V. Vo ◽  
Pham Cam Nam ◽  
Mai Van Bay ◽  
Nguyen Minh Thong ◽  
Nguyen Duc Cuong ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Density Functional Theory Study ◽  
Hydrogen Atoms ◽  
Functional Theory
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