Agglomeration vs. Localization of Hydrogen in bcc Fe vacancies

S. SIMONETTI, A. JUAN, G. BRIZUELA

Lyon, France.

Congreso; World Hydrogen Energy Congress (WHEC-18); 2006

International hydrogen Association

Severe embrittlement can be produced in many metals by small amounts of hydrogen. The interactions of hydrogen with lattice imperfections are important and often dominant in determining the influence of this impurity on the properties of solids. The interaction between four-hydrogen atoms and a BCC Fe structure having a vacancy has been studied using a cluster model and a semiempirical method. For a study of sequential absorption, the hydrogen atoms were positioned in their energy minima configurations, near to the tetrahedral sites neighbouring the vacancy. VH2 and VH3 complexes are energetically the most stables in BCC Fe. The studies about the stability of the hydrogen agglomeration gave as a result that the accumulation is unfavourable in complex vacancy-hydrogen with more than three atoms of hydrogen.