Modelling of Excess Vacancy Annihilation at Different Types of Sinks

0363694 - ÚFM 2012 RIV GB eng J - Journal Article
Fischer, F. D. - Svoboda, Jiří - Appel, F. - Kozeschnik, E.
Modelling of Excess Vacancy Annihilation at Different Types of Sinks.
Acta Materialia. Roč. 59, č. 9 (2011), s. 3463-3472. ISSN 1359-6454. E-ISSN 1873-2453
R&D Projects: GA ČR GAP108/10/1781
Institutional research plan: CEZ:AV0Z20410507
Keywords : Vacancies * Annihilation * Substitutional diffusion
Subject RIV: BJ - Thermodynamics
Impact factor: 3.755, year: 2011

The equilibrium site fraction of vacancies increases with temperature and, thus, annealing and rapid quenching may lead to states with a significant vacancy supersaturation. Excess vacancies can then gradually annihilate at available sinks represented by jogs at dislocations, by grain boundaries or free surfaces. Significant supersaturation by vacancies may also lead to the nucleation and growth of Frank loops acting as additional sinks. Three models corresponding to three different annihilation mechanisms are developed in this paper. They refer to annihilation of excess vacancies at jogs at dislocation with a constant density, at homogeneously distributed Frank loops with a constant density and at grain boundaries. The simulations based on the models are performed for individual annihilation mechanisms under isothermal and non-isothermal conditions as well as for simultaneous annihilation of vacancies at Frank loops and dislocation jogs and grain boundaries using different cooling conditions.
Permanent Link: http://hdl.handle.net/11104/0199401