Loading...
Please wait, while we are loading the content...
Similar Documents
Effects of thermal-solutal convection on temperature and solutal fields under various gravitational orientations
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Wang, Jai-Ching |
| Copyright Year | 1993 |
| Description | Semiconductor crystals such as Hg(1-x)CD(x)Te grown by unidirectional solidification Bridgmann method have shown compositional segregations in both the axial and radial directions. Due to the wide separation between the liquidus and the solidus of its pseudobinary phase diagram, there is a diffusion layer of higher HgTe content built up in the melt near the melt-solid interface which gives a solute concentration gradient in the axial direction. The value of effective diffusion coefficient calculated from fitting of the data to 1D model varies with Hg(1-x)Cd(x)Te growth conditions. This indicates that the growth condition of the Hg(1-x)Cd(x)Te is not purely diffusion controlled. Because of the higher thermal conductivity in the melt than that in the crystal in the growth system, there is a thermal leakage through the fused silica crucible wall near the melt-solid interface. This gives a thermal gradient in the radial direction. Hart, and Thorpe, Hutt and Soulsby have shown that under such conditon a fluid will become convectively unstable as a result of different diffusitivities of temperature and solute. It is quite important to understand the effects of this thermosolute convection on the compositonal segregation in both axial and radial directions in the unidirectionally solidified crystals under various gravitational directions. To reach this goal, we start with a simplified problem to study the effects of thermal-solutal convection on the temperature and solutal fields under various gravitional orientations. We begin by reviewing model governing equations. |
| File Size | 216322 |
| Page Count | 6 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19940019978 |
| Archival Resource Key | ark:/13960/t5fc0064m |
| Language | English |
| Publisher Date | 1993-11-01 |
| Access Restriction | Open |
| Subject Keyword | Materials Processing Mercury Cadmium Tellurides Phase Diagrams Directional Solidification Crystals Liquid-solid Interfaces Semiconductors Materials Thermal Conductivity Solutes Diffusion Diffusion Coefficient Microgravity Convection Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
