ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Two kinds of α-Si3N4 powders with different properties (high purity and low purity) were pressureless sintered using MgAl2O4-ZrO2 as sintering additives. The grain growth was controlled by sintering time and temperature. The fracture toughness was determined using indentation microfracture (IM) and single-edge-precracked-beam (SEPB) methods. A discrepancy of fracture toughness was found between the values obtained by these two methods, and the SEPB method provided higher fracture toughness than the IM method. Materials with more large elongated Si3N4 grains gave higher fracture toughness, R-curve behavior and larger discrepancy. This is contributed to the effects of grain bridging, pull-out and deflection by the large elongated Si3N4 grains. Comparing the specimens from two kinds of α-Si3N4 powders with different purity level, both gave high fracture toughness of over 9 MPa · m1/2 by the SEPB method, while the E10 samples have a little higher flexural strength.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1004724814778
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