ISSN:
1573-2673
Keywords:
Paticulate composites
;
cxynitride glasses
;
fracture toughness
;
Chevron-notch method.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The fracture toughness K1c and the effective fracture surface energy γeff, of oxynitride glass (m)/SiC(p) brittle particulate composites were measured by means of stable fracture tests, using chevron-notch three-point bend specimens. In comparison to oxide glasses, the oxynitride glass matrix is noticeably tougher: K1cm = 1.2 MPa. $$\sqrt m$$ and γeff = 5 J/m2. The addition of SiC particles, 6 μm in diameter, results in a significant toughening: K1c = 2.5 MPa. $$\sqrt m$$ and γeff = 9.1 J/m2 for the composite with 40 vol\% SiC. In such systems, with strong particle-matrix interfacial bonding, and where (Ep, K1cp, σrp) 〉 (Em, K1cm, σrm), the main toughening contribution is due to a discrete pinning of the crack by particles near the crack tip in conjunction to bowing of the crack front between particles, and to a small scale bridging mechanism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007474415485
