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Zero stress aging in notched multi‐component glass fibers
Author(s) -
Van Sant Joseph,
Diercks David,
Fett Theo,
Reimanis Ivar E.
Publication year - 2019
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/jace.16507
Subject(s) - materials science , composite material , glass fiber , ultimate tensile strength , fracture (geology) , fiber , soda lime , fracture mechanics , stress (linguistics) , soda lime glass , philosophy , linguistics
Degradation of glass under zero applied load in the presence of humidity at ambient temperature is of great interest to the container and fiber glass industries. The phenomenon is well documented for fused silica used in optical fibers, but has not been studied in detail for multi‐component glasses. In this work notches of varying length (500‐1500 nm) were placed with a focused ion beam into two types of multi‐component glass fibers, E‐glass (48 μm diameter) and soda‐lime‐silicate (35 μm diameter). Notched specimens were exposed to dry and humid conditions for up to 32 days. Transmission electron microscopy revealed the presence of extensive reaction products within the root of the notch, even after only 1 day of aging in the nominally dry environment for the soda‐lime‐silicate glass. Surprisingly, the extensive reactions have no measurable effect on the fiber strength. The uniaxial tensile strength of the notched glass fibers, measured with the fracture surface mirror radius method, does not follow a classic fracture mechanics prediction, implying that the notches are not classic Griffith flaws. Fracture mechanics is applied to show that sharpness at the notch base may be important, especially when subcritical crack growth is present during the strength measurement.