I. Dlouhy et al., FRACTURE CHARACTERISTICS OF BOROSILICATE GLASSES REINFORCED BY METALLIC PARTICLES, Fatigue & fracture of engineering materials & structures, 20(9), 1997, pp. 1235-1253
The fracture behaviour of borosilicate glass reinforced by molybdenum
and/or vanadium particles has been investigated. For the addition of 5
vol% molybdenum particles, two processing procedures have been tested
and the influence of volume fraction of vanadium particles (in the ra
nge 2 to 30 vol%) on fracture resistance has been assessed. The use of
chevron notched specimens in three-point bending has been shown to be
a reliable method for the evaluation of fracture toughness even at to
ughness levels of order 0.7 to 1.3 MPa root m. The existence of subtle
differences in fracture behaviour of glass-composites having comparab
le volume fractions of molybdenum particles but obtained by two differ
ent processing procedures has been established by statistical treatmen
t of the fracture toughness data. An increase in the volume fraction o
f metallic particles results in an increase of the fracture resistance
and the measured fracture toughness level. Toughening mechanisms whic
h have been identified include both the plastic deformation of particl
es and the bridging of cracks by ductile particles. Some particle clea
vage and debonding has been observed, which indicates that a decrease
in particle plasticity, probably induced by processing or due to const
raints imposed by the rigid matrix, is responsible for a smaller than
expected enhancement of the fracture toughness.