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In-Situ Crystallization of a Lithium Disilicate Glass--Effect of Pressure on Crystal Growth RateCrystallization of a Li2O.2SiO2 (LS2) glass subjected to a uniform hydrostatic pressure of 4.5 GPa and 6 GPa was investigated up to a temperature of 750 C. The density of the compressed glass is about 2% greater at 4.5 GPa than at 1 atm and, depending upon the processing temperature, up to 10% greater at 6 GPa. Crystal growth rates investigated as a function of temperature and pressure show that lithium disilicate crystal growth is an order of magnitude slower at 4.5 GPa than 1 atm resulting in a shift of +45 C (plus or minus 10 C) in the growth rate curve at high pressure compared to 1 atm condition. At 6 GPa lithium disilicate crystallization is suppressed entirely, while a new high pressure lithium metasilicate crystallizes at temperatures 95 C (plus or minus 10 C) higher than those reported for lithium disilicate crystallization at 1 atm. The decrease in crystal growth rate with increasing pressure for lithium disilicate glass up to 750 C is related to an increase in viscosity with pressure associated with fundamental changes in glass structure accommodating densification.
Document ID
20080009664
Document Type
Reprint (Version printed in journal)
Authors
Fuss, T.
(Missouri Univ. Rolla, MO, United States)
Ray, C. S.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Lesher, C. E.
(California Univ. Davis, CA, United States)
Day, D. E.
(Missouri Univ. Rolla, MO, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2006
Subject Category
Composite Materials
Distribution Limits
Public
Copyright
Other

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