научная статья по теме ON MICROMECHANISMS OF HYDROGEN SUPERPLASTICITY AND EMBRITTLEMENT OF SOME SOLIDS AND RELEVANCE TO THE PROBLEMS OF SAFETY AND STANDARTIZATION OF MATERIALS Комплексное изучение отдельных стран и регионов

Текст научной статьи на тему «ON MICROMECHANISMS OF HYDROGEN SUPERPLASTICITY AND EMBRITTLEMENT OF SOME SOLIDS AND RELEVANCE TO THE PROBLEMS OF SAFETY AND STANDARTIZATION OF MATERIALS»

Водородная энергетика и транспорт Конструкционные материалы

Hydrogen energy and transport

Structural materials

ON MICROMECHANISMS OF HYDROGEN SUPERPLASTICITY AND EMBRITTLEMENT OF SOME SOLIDS, RELEVANCE TO THE PROBLEMS OF SAFETY AND STANDARDIZATION OF

MATERIALS

T. Nejat Veziroglu

Yuri S. Nechaev

Yu. S. Nechaev12, T. N. Veziroglu1

1 University of Miami, Coral Gables, Florida 33124, USA

2 Permanent address: Bardin Central Research Institute for Ferrous Metallurgy, Kurdyumov Institute of Metal Physics, Moscow 107005, Russia

T. N. Veziroglu

Dr. Veziroglu, a native of Turkey, graduated from the City and Guilds College, the Imperial College of Science and Technology, University of London, with degrees in Mechanical Engineering (A.C.G.I., B.Sc.), Advanced Studies in Engineering (D.I.C.) and Heat Transfer (Ph.D.).

After serving in some Turkish Government agencies as a Technical Consultant and Deputy Director of Steel Silos, and then heading a private company, he joined the University of Miami Engineering Faculty, and served as the Director of Graduate Studies, Mechanical Engineering (initiating the first Ph.D. Program in the College of Engineering), Chairman of the Department of Mechanical Engineering, and the Associate Dean for Research. Presently, he is the Director of the Clean Energy Research Institute.

Dr. Veziroglu teaches Heat Transfer, Mass Transfer, Nuclear Engineering, Solar Energy and Hydrogen Energy. His research interests are instabilities in Boiling Water Reactors, Interstitial Heat Transfer, Renewable Energy Sources and Hydrogen Energy System. He has published some 350 scientific reports and papers, edited about 200 volumes of proceedings, and is the Editor in Chief of the monthly scientific journals International Journal of Hydrogen Energy. He has been an invited lecturer and/or consultant on energy research and education to many countries, including Argentina, Australia, Bahrain, Brazil, Canada, China, Columbia, Egypt, England, France, Germany, India, Italy, Japan, Kuwait, Malaysia, Nepal, Pakistan, the Philippines, Russia, Saudi Arabia, Switzerland, Turkey, Ukraine and Venezuela, and to several universities and research organizations in the United States.

Dr. Veziroglu organized the first major conference on Hydrogen Energy: The Hydrogen Economy Miami Energy (THEME) Conference, Miami Beach, March 1974, and proposed the Hydrogen Energy System. Subsequently, he organized several conferences and symposia on Alternative Energy Sources, Environment, Hydrogen Energy, Heat and Mass Transfer, and Remote Sensing.

Dr. Veziroglu has membership in some twenty scientific organizations, has been elected to the Grade of Fellow in the British Institution of Mechanical Engineers, the American Society of Mechanical Engineers and the American Association for the Advancement of Science, and is the Founding President of the International Association for Hydrogen Energy.

Dr. Veziroglu has been the recipient of several international awards, including Turkish Presidential Science Award, 1975, Honorary Professorship, Xian Jiaotong University, Xian, China, 1981, I. V. Kurchatov Medal, Kurchatov Institute of Atomic Energy, Moscow, USSR, 1982, Energy for Mankind Award, 1986, Twenty-Five Years' Service Award, American Nuclear Society, 1987, Turkish Superior Service to Mankind Award, 1991, Honorary Doctorate, Anadolu University, Eskisehir, Turkey, 1998, Honorary Member, Argentinean Academy of Sciences, 2000, and Honorary Doctorate, Donetsk State Technical University, Donetsk, Ukraine, 2001. In 2000, he was nominated for the Nobel Prize in Economics for both envisioning the Hydrogen Economy, and striving towards its realization.

s

Nechaev Yuri S.

Nechaev Yuri S. was born 04 August 1939 in Voronezh city, Russia. He had graduated the Moscow Steel & Alloys Institute (now — Technical University) in 1962.

From 1962 till 1968 he worked (as a researcher) in the All-Union Research Institute of Aviation Materials. In 1968 he defended the Ph.D. thesis on "Elaboration of the Method and Studying of the Relaxation Properties of Vacancies in Metals".

From 1968 till 1989 he worked in the Moscow Steel & Alloys Institute (Technical University) as an associate professor of the Physical Chemistry Department. In 1975-1976 he had perfomed 10 months' researches of lattice defects in metals at Kyoto University, Japan (in Laboratory of Prof. J.-I. Takamu-ra). In 1982 he defended the Dr.Sc. thesis on the topic "Stable Segregation Phases at Dislocations and Their Influence on Diffusion Processes in Aluminum Alloys". In 1984-1987 he worked as an associate professor of the Physics Department in the Addis-Ababa University (Ethiopia).

From 1989 till 1992 he worked as a Head of the Materials Science & Metal Physics Department in the Karaganda Metallurgical Institute (Technical University), Kazakhstan, and from 1992 till 1995 — as a full professor of the Department.

From 1993 till 1996 he worked (in parallel) in the Moscow Institute of Electronics & Mathematics (Technical University) as a chief researcher, professor of the Materials Science Department.

I.S. Netchaev has had more than 100 scientific publications; he has participated in many International Research Conferences, particularly, as an invited lecturer. In 1995 he was elected to Membership in the New-York Academy of Sciences (USA), ID member # 409313-2.

From 1996 till 1998 he had worked as a chief researcher, professor in the A.A.Baikov Institute of Metallurgy & Materials Science of the Russian Academy of Sciences; from 1998 till nowadays he has worked as a chief researcher, professor in the G.V. Kurdyumov Institute of Metal Physics & Functional Materials, within the I. P. Bardin Central Research Institute for Ferrous Metallurgy (Moscow, Russia).

Introduction

As has been formulated in Report [1] of the Basic Energy Sciences Workshop of the U.S. Department of Energy (DoE), May 13-15, 2003, on Hydrogen Production, Storage and Use, in chapter Safety in Hydrogen Economy (p. 126-127), corrosion and hydrogen embrittlement of materials are closely connected to details of their microstructure, and, in particular, to the segregation and diffusion processes that occur at internal interfaces and associated defects, such as dislocations; micromechanisms of such processes are not well understood. As has been also noted [1] in Potential Impacts (p. 127), fundamental knowledge of hydrogen embrittlement of metals and welded joints would enable the setting of standards for the materials used in building a hydrogen infrastructure. As has been noted [1] in chapter Basic Research Challenges for Hydrogen Storage (in item Safety, p. 49), fundamental research will be needed to understand materials' hydrogen degradation and failure processes to allow design of improved materials for hydrogen storage. Hence, Research Directions have been formulated by the U.S. DoE as: Understanding of the Basic Physics of Hydrogen Transport in Metals and Hydrogen-assisted Damage Mechanisms.

Some fundamental problems of these research directions and their solution ways are considered in the present contribution.

Fundamental Problems (A, B)

(IA) One of the problems in question is revealing physics (micromechanisms) of the so-called

"mechanical instability", i. e., a sharp plastification (up to superplasticity-like behavior and amor-phization) of Fe, Pd, V, Ta, Nb, Zr, TiNi, Laves phases, Zr3Rh in hydrogen atmosphere or under electrolytic hydrogen charging (the known experimental data (1982-2002), [2]).

(IIA, B) The second problem (related with IA) is revealing micromechanisms of the high pressure hydrogen influence on plasticity, strength, cyclic fatigue, friction and wear of steels and other industrial alloys used in hydrogen power (the known experimental and technological data (1985-2003), [3]).

(IIIA) The third problem (also related with IA) is revealing physics (micromechanisms) of the hydrogen plastification and hydrogen superplas-ticity of titanium and titanium-based industrial alloys (the known experimental and technological data (1985-2003), [4]).

(IVB) On the other hand, the urgent problems are of physics (micromechanisms) of different hydrogen degradation, embrittlement, cracking and blistering of metals and industrial alloys (the experimental and technological data (1970-2003), [3-5]).

Solution Ways of Problems (A)

The most data of Problems IA, IIA, IIIA can be interpreted on the basis of the use of challenging results [6-10], including a model of a periodic melting-like transition at grain boundary nan-oregions (GBNR) under their "bombarding" by moving dislocations with hydrogen segregation "nanoatmospheres" and by deformation vacancies and complexes of vacancies with hydrogen atoms [11-21]. It is related to a periodic vacancy-hydro-

gen clustering (Y. Fukai et al. (1995-2001), [6]) at GBNR (a Frenkel type vacancy melting).

Solution Ways of Problems (B)

The most data of Problems IIB, IVB can be interpreted on the basis of the use of challenging results [11-27]; some of them are the following.

Firstly [15, 20], on the basis of analysis of the experimental data on apparent solubility and diffusivity of hydrogen in electrolyticallly charged maraging steel and iron-Armco, the hydrogen fugacity (pressure) of molecular hydrogen in metallic materials (under hydrogen charging) has been evaluated as ~102-103 bar, for typical current densities of 10-100 A/m2. The hydrogen fugacity of the same order of magnitude has been also estimated by using the deformation-mechanism maps with respect to the experimental data on blistering and cracking of low alloyed steel (under electrolytic hydrogen charging). It is consistent with the recent results on high pressure hydrogen generation by PEM electrolysis [28] and electrolytic production of ultra-high pressure hydrogen fuel without a compressor [29]. It can be used for experimental studies (modeling) of hydrogen permeability and hydrogen-assisted damage processes, w

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