Title of article :
Continuum simulations of the formation of Kirkendall-effect-induced hollow cylinders in a binary substitutional alloy Original Research Article
Author/Authors :
Hui-Chia Yu، نويسنده , , Dong-Hee Yeon، نويسنده , , XIAOFAN LI ، نويسنده , , K. Thornton، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2009
Pages :
13
From page :
5348
To page :
5360
Abstract :
We examine binary substitutional diffusion in cylindrical diffusion couples in which free surfaces are considered explicit vacancy sources and sinks. The central region of the cylinder is initially occupied by an atomic species with a larger hop frequency, while the outer region is occupied by another atomic species with a smaller hop frequency. Equilibrium vacancy concentration is maintained at free surfaces that serve as vacancy sources and sinks. In the crystal, diffusion is governed by the standard diffusion equations with analytically evaluated diffusion coefficients. The void growth dynamics and hollow cylinder formation stemming from the Kirkendall effect are simulated. Our results show that the Kirkendall void growth involves two competing factors. One is the net inward vacancy flux that favors void growth. The other is the Gibbs–Thomson effect that favors void shrinkage. We compute the critical initial radius for void growth above which the Kirkendall effect dominates over the Gibbs–Thomson effect. The fully grown void radius and the elapsed time to the fully grown size are also predicted for different fast-diffuser volume fractions and fast-to-slow diffuser atomic hop frequency ratios.
Keywords :
simulation , Vacancies , Substitutional diffusion , Modelling , Hollow object formation
Journal title :
ACTA Materialia
Serial Year :
2009
Journal title :
ACTA Materialia
Record number :
1144519
Link To Document :
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