Origin of hydrogen embrittlement in vanadium-based hydrogen separation membranes

Ko, Won-Seok; Jeon, Jong Bae; Shim, Jae-Hyeok; Lee, Byeong-Joo

doi:10.1016/j.ijhydene.2012.06.075

Cited by 28 publications

(3 citation statements)

References 37 publications

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“…However, the metallic membranes without alloying elements always have the problem of H 2 embrittlement, which causes degradation of mechanical and H 2 separation properties (Ko, Jeon, Shim, & Lee, 2012;Lin, 2001;Nambu et al, 2007;Yun & Oyama, 2011). However, the metallic membranes without alloying elements always have the problem of H 2 embrittlement, which causes degradation of mechanical and H 2 separation properties (Ko, Jeon, Shim, & Lee, 2012;Lin, 2001;Nambu et al, 2007;Yun & Oyama, 2011).…”

Section: Metallic and Alloy Membrane Reactorsmentioning

confidence: 99%

Membrane reactors for hydrogen production from coal

Dong

Lin

2015

Membrane Reactors for Energy Applications and Basic Chemical Production

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Section: Metallic and Alloy Membrane Reactorsmentioning

confidence: 99%

Membrane reactors for hydrogen production from coal

Dong

Lin

2015

Membrane Reactors for Energy Applications and Basic Chemical Production

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“…Hydrogen embrittlement (HE) is a severe material degradation mechanism which deteriorates the mechanical properties of materials [1][2][3]. Once hydrogen diffuses into a host matrix, materials usually fail at low stress levels when compared to their hydrogen free counterparts [4,5].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Role of Volumetric Transformation Strain on the Relaxation Stress and the Corresponding Hydrogen Interstitial Concentration in Niobium Matrix

Bal

2017

Advances in Materials Science and Engineering

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The effects of relaxation stress on the hydrogen concentration in Niobium- (Nb-) H media were investigated by iterative numerical modeling approach. To calculate the transformation strain, relaxation stress, and corresponding relaxed hydrogen concentration around an edge dislocation, a new third-order polynomial formulation was utilized in the model. With the aid of this polynomial, hydrogen induced relaxation stress never exceeds the dislocation stress, which indicates that the total stress field never turns to compressive state and diverges the results. The current model calculates the hydrogen concentration not only in the vicinity of an edge dislocation but also far away from the dislocation. Furthermore, the effect of relaxation stress on the interaction energy was also captured in the model. Overall, the current findings shed light on the complicated hydrogen embrittlement mechanisms of metallic materials by demonstrating that hydrogen induced relaxation has a significant effect on the hydrogen atom concentration and the interaction energy between the existing internal stress field and the solute hydrogen atom.

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“…Recently, much research has been carried out using atomistic simulation to reveal aspects of the embrittlement mechanisms [59], [90], [91], [101]. Evidence that the passage of hydrogen is hindered by lattice imperfections which tend to attract and bind it (trapping) has been proven by Smith et al .…”

Section: Theories For Hydrogen Trappingmentioning

confidence: 99%

Mobility of Hydrogen-Vacancy Complexes in Nickel

Madappa¹

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Atomistic simulations of the mechanism of hydrogen pile-up around a single vacancy and its effect on the vacancy mobility are performed to investigate possible nanoscale mechanisms for hydrogen embrittlement. A detailed study of the interactions of hydrogen with the vacancy point defect in nickel is presented. In particular we discuss the trapping of multiple hydrogen atoms in a monovacancy. We show that a single vacancy is capable of trapping 12 or more hydrogen atoms. The trapping energy is found to be approximately equal to -0.14 eV. We find that the interstitial hydrogen in the bulk lattice prefers to be located at octahedral interstitial positions which is in agreement with previous theoretical works in the literature. The trapping energy is obtained for the relaxed octahedral and tetrahedral positions inside the vacancy, with a site preference for octahedral positions. The influence of the vacancy defect is not limited to its volume but also extends to the octahedral sites of its first-nearestneighbour atoms. The interstitial hydrogen atoms prefer to cluster around the single vacancy than to remain at unrelated interstitial locations in the bulk lattice. The hydrogen-vacancy cluster is extremely stable in nature.We also look at the effect of pressure on the trapping and migration energies of the hydrogen-vacancy complex. We find that the magnitude of the energy is influenced by stress. The hydrogen atom cloud around the vacancy defect also exerts some resistance towards the migration of the defect.iii Acknowledgments I take this opportunity to express my sincere gratitude to my supervisor, Professor Ronald E. Miller whose vision, guidance and encouragement aided me to successfully undertake and complete this research assignment. He introduced me to the world of computational material science and was always there to listen to the hurdles I faced.His advice and ideas to tackle problems were indispensable without which this project would not have been possible. In addition, I would like to thank the thesis review committee for their time and effort. I would like to share this moment of happiness with my parents and thank them for their constant love, encouragement and support. My parent's faith and sacrifices over the years have always kept me moving forward towards my goals. I am thankful to Dr. Jean-François Joly from my research group for his time and valuable advice during my research tenure. In addition I would like to express my appreciation to my research group mate Ms. Roxana Barceló Singh for her thoughts, ideas and valuable discussions. I also gratefully acknowledge the cooperation that I received from other faculty members and administrative staffs of my Department. Lastly I would like to recognize the Department of Mechanical and Aerospace Engineering and the Faculty of Graduate Studies and Research of Carleton University for giving me the opportunity and facility for pursuing my masters program. iv To my mother v

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Origin of hydrogen embrittlement in vanadium-based hydrogen separation membranes

Cited by 28 publications

References 37 publications

Membrane reactors for hydrogen production from coal

Membrane reactors for hydrogen production from coal

Numerical Investigation of the Role of Volumetric Transformation Strain on the Relaxation Stress and the Corresponding Hydrogen Interstitial Concentration in Niobium Matrix

Mobility of Hydrogen-Vacancy Complexes in Nickel

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