Bridgman Crystal Growth of An Alloy With Thermosolutal Convection Under Microgravity Conditions  

Oleh:

Garimella, Suresh V. ; Abbaschian, Reza ; Simpson, James E. ; Groh III, Henry C. de

Jenis: Article from Bulletin/Magazine
Dalam koleksi: Journal of Heat Transfer vol. 123 no. 5 (Oct. 2001), page 990-998.
Topik: gravity; bridgman crystal growth; alloy; thermosolutal convection; microgravity conditions

Ketersediaan

Perpustakaan Pusat (Semanggi) Nomor Panggil: JJ90.2 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

Lihat Detail Induk

Isi artikel

The solidification of a dilute alloy (bismuth - tin) under Bridgman crystal growth conditions is investigated. Computations are performed in two dimensions with a uniform grid. The simulation includes the species concentration, temperature and flow fields, as well as conduction in the ampoule. Fully transient simulations have been performed, with no simplifying steady state approximations. Results are obtained under microgravity conditions for pure bismuth, and for Bi - 0.1 at. % Sn and Bi - 1.0 at. % Sn alloys, and compared with experimental results obtained from crystals grown in the microgravity environment of space. For the Bi - 1.0 at. % Sn case the results indicate that a secondary convective cell, driven by solutal gradients, forms near the interface. The magnitude of the velocities in this cell increases with time, causing increasing solute segregation at the solid / liquid interface. Finally, a comparison between model predictions and results obtained from a space experiment is reported. The concentration - dependence of the alloy melting temperature is incorporated in the model for this case. Satisfactory correspondence is obtained between the predicted and experimental results in terms of solute concentrations in the solidified crystal.

Opini Anda

Klik untuk menuliskan opini Anda tentang koleksi ini!

Kembali