0
REVIEW ARTICLES: Solidification

Float Zone Modelling: Transport Phenomena and Morphological Stability

[+] Author and Article Information
G. W. Young

Department of Mathematical Sciences, University of Akron, Akron OH 44325-4002

Appl. Mech. Rev 43(5S), S63-S69 (May 01, 1990) doi:10.1115/1.3120853 History: Online April 30, 2009

Abstract

A model is presented for a float zone established in a vertical sheet. Heat transfer between the system (melt, feed and crystal) and the surrounding environment (including the heating source) is assumed to take place via radiation. Asymptotic solutions for the temperature, concentration, and melt flow profiles and the melting, solidifying and melt/gas interfacial shapes are developed in the limit of small aspect ratio (zone half-width/length) and weak surface tension driven flows. We find that convective heat transport leads to melt back of the solidification front near the edges. Further, lateral solute segregation is due to both convective effects and curved solidification fronts. Increasing the flow or increasing the velocity of solidification leads to increased lateral solute segregation in melts that are not well mixed. Hence, flat solidification fronts may not yield flat concentration profiles. To reduce the level of convection, hot wall, low temperature gradient float zone techniques are also investigated. Morphological stability of the solidification front is of concern for such heating configurations. We present the results of a linear stability analysis in the limits of small segregation coefficient, slow velocities of solidification, and large surface heat transfer. It is found that shorter melt zones are less susceptible to long wavelength morphological instabilities.

Copyright © 1990 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In