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Global stabilities and selection of lamellar eutectic growth in directional solidifation

Jian-Jun Xu 1Xiang-Ming Li 2

1. McGill Unversity, 805 shebrooke street, west, Montreal H3A0B9, Canada
2. School of Materials Science and Engineering, Kunming University of Science and technology, Kunming 650093, China

Abstract

The present paper is concerned with the global stability mechanisms of the steady state of lamellar eutectic  growth in directional solidification, which depends on two free parameters the Peclect number ε and the tilted angle φ.

   We perform the asymptotic analysis in the limit of Peclet number ε→0 and the  segregation coefficient parameter κ→1 and find that the system involves two types of global instabilities: the low frequency (LF) instability and the oscillatory wave (OS) instabilities.  Each of these stability mechanisms may have two types of modes,  symmetric (S)-modes and anti-symmetric (A)-modes. The neutral LF modes yield the steady interface-patterns, while the neutral oscillatory wave modes yield the oscillatory interface-patterns. It appears that similar to the case of deep cellular growth, there is no selection in eutectic growth, neither for the steady state,  nor for the oscillatory state.  The neutral curves of these two types of global instability mechanisms on(φ,ε) -plane have the intersection, which determines the transition of the steady periodic pattern to the oscillatory pattern.

 

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Related papers

Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, General Session 1, by Jian-Jun Xu
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-03-05 18:20
Revised:   2013-03-23 15:18