Effect of Water Penetration on the Strength and Toughness of Silica Glass
-
Autor:
Wiederhorn, SM; Fett, T; Rizzi, G; Funfschilling, S; Hoffmann, MJ; Guin, JP
-
Quelle:
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 2011, Band 94, Heft S1, S. 196-203
Abstract
In this paper, we discuss the effect of water on the strength and
static fatigue of silica glass. When a crack is formed in silica glass,
the surrounding environment rushes into the crack; water then diffuses
from the environment into the newly formed fracture surfaces to generate
a zone of swelling around the crack tip. Because the swollen material
is constrained from expanding by the surrounding glass, a zone of
compressive stress is generated at the fracture surface around the crack
tip. The results are similar to those found for transformation
toughened zirconium oxide, with the exception that the transformation
zone in silica glass grows with time, so that the effect gets
progressively stronger. Using diffusion data from the literature, we
show that the diffusion of water into silica glass can explain several
significant experimental observations: the reported strengthening of
silica glass by soaking in water at 88 degrees C; an increase in the
slope of dynamic fatigue curve by prior exposure to water at 88 degrees
C; the observation of a static fatigue limit in silica glass at very low
values of the applied stress-intensity factor; and the observation of
crack face displacements caused by water penetration into the glass at
the crack tip.