Crack silicon nitride

Ohji T (1994) Tensile Creep Rupture And Subcritical Crack Growth of Silicon Nitride. In Hoffmann MJ, Petzow G (eds) Tailoring of Mechanical Properties of Si3N4 Ceramics. Kluwer Academic Publishers, Netherlands, p 339... 

Kovar, D., Thouless, M.D., and Halloran, J.W. (1998), Crack deflection and propagation in layered silicon nitride/boron nitride ceramics , J. Am. Ceram. Soc., 81, 1004-1012. 

Blugan, G., Orlovskaya, N., Lewis, M., Kuebler, J., Multilayer silicon nitride laminates exhibiting high fracture toughness and crack deflection, Key Eng. Mater., 280-283, 1863-1868, 2004. 

The bulk densities of all the materials were determined using Archimedes method (AS 1774.5, 1979). The Vickers indentation technique was used to measure the hardness in each case. The applied load in the Vickers hardness tests was 10 kg for silicon nitrides and sialons. However, using the same load produced severe lateral cracking in silicon carbides around indents, which prevented the accurate measurement of the diagonals of indents. Therefore the load was reduced to 0.3 kg for silicon carbide samples. 

Fig. 4.14 Cavity formation in silicon nitride, (a) Lenticular cavities form at grain boundaries for grades of silicon nitride bonded by highly refractory glasses, (b) Crack-like cavities form at boundaries for grades of silicon nitride that are less refractory, (c) In addition to these interfacial cavities, more irregular, /urn-size cavities are also observed at multigrain junctions in silicon nitride. From Hockey and Wiederhom,94 Luecke et a/.101 and Wiederhom et al.100...

Early work (e.g., Refs. 44 and 45) on silicon nitride ceramics for a limited range of high temperature cyclic loading conditions led to the hypothesis that the mechanisms of cyclic and static fracture at elevated temperature are identical, and that the cyclic crack growth rates can be predicted on the basis of static fracture data. One of the techniques commonly used to derive cyclic crack growth rates solely on the basis of static load fracture data involves integration of the relationship in Eqn. (13) over the duration of the fatigue cycle such that... 

U. Ramamurty, T. Hansson, and S. Suresh, High-Temperature Crack Growth in Monolithic and SiCVReinforced Silicon Nitride Under Static and Cyclic Loads, J. Am. Ceram. Soc., 77[11], 2985-2999 (1994). 

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