Positron annihilation in vacancies at grain boundaries in metals

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Authors	KURIPLACH Jan MELIKHOVA O. HOU M. VAN PETEGEM S. ZHURKIN E. ŠOB Mojmír
Year of publication	2008
Type	Article in Periodical
Magazine / Source	Applied Surface Science
MU Faculty or unit	Faculty of Science
Citation
Field	Solid matter physics and magnetism
Keywords	positron annihilation; vacancies; grain boundaries
Description	The behavior of vacancies in selected coherent grain boundaries (GBs) in Fe and Ni is studied by means of molecular dynamics simulations. Corresponding positron lifetimes are calculated using the atomic superposition method. There is a difference between the vacancy behavior in Fe and Ni in dependence on temperature. In Ni, vacancies at GBs appear to diminish substantially their free volume (and lifetime) with the increasing temperature, which can be attributed to vacancy delocalization. Contrary, GB vacancies remain stable up to apparently higher temperatures in Fe.
Related projects:	Physical and chemical properties of advanced materials and structures Theoretical studies of structure and magnetic properties of internal interfaces in metallic materials