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Indentation Behavior of Soda‐Lime Silica Glass, Fused Silica, and Single‐Crystal Quartz at Liquid Nitrogen Temperature
Author(s) -
Kurkjian Charles R.,
Kammlott Gunther W.,
Chaudhri M. Munawar
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08241.x
Subject(s) - materials science , quartz , cracking , composite material , indentation , liquid nitrogen , soda lime , shear (geology) , vickers hardness test , crystal (programming language) , mineralogy , metallurgy , microstructure , chemistry , organic chemistry , computer science , programming language
In an attempt to elucidate the processes involved in the formation of indentation impressions, Vickers hardness measurements have been made on soda‐lime silica glass, fused silica, and crystalline quartz indented at room temperature and 77 K. The hardness of all three materials increases by a factor of ∼2.5 on cooling to liquid nitrogen temperature. High‐magnification SEM photographs revealed that the deformation and cracking patterns of the glasses changed strikingly: no shear lines were observed within the indentations, and ring cracking occurred instead of radial/median cracking. In addition, cracking occurs at much higher loads than at room temperature. The hardness results have been explained in terms of volume flow (densification) rather than shear flow (viscous or plastic) for the glasses at low temperature. The quartz crystal, on the other hand, deformed plastically at both room temperature and 77 K. Cracking differences result from changes in both flow and water activity