National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System.

DE2002797636

Publication Date	2002
Personal Author	Shen, Y.
Page Count	60
Abstract	In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales.
Keywords	Microstructure Solidification Correlations Dendritic structure Shape Solutes Temperature gradients Validation Velocity Scaling laws Theses Dendrites
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Iowa State Univ., Ames.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
Title Note	Thesis.
NTIS Issue Number	200223

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System.

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System.
DE2002797636

Publication Date	2002
Personal Author	Shen, Y.
Page Count	60
Abstract	In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales.
Keywords	Microstructure Solidification Correlations Dendritic structure Shape Solutes Temperature gradients Validation Velocity Scaling laws Theses Dendrites
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Iowa State Univ., Ames.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
Title Note	Thesis.
NTIS Issue Number	200223