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Crystal shape evolution in detached bridgman growth (Document No: 20140002981)
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Volz, M. P. Mazuruk, K. |
| Copyright Year | 2013 |
| Description | Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described. |
| File Size | 397267 |
| Page Count | 14 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20140002981 |
| Archival Resource Key | ark:/13960/t41s1sw15 |
| Language | English |
| Publisher Date | 2013-08-11 |
| Access Restriction | Open |
| Subject Keyword | Space Processing Crystal Growth Nucleation Crystallization Spaceborne Experiments Crystals Crucibles Silicon Alloys Germanium Alloys Melts Crystal Growth Dynamic Stability Germanium Shapes Microgravity Bridgman Method Menisci Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Presentation |
