Measurement of Indentation Fracture Toughness of Silicon Nitride Ceramics: II, Effect of the Experimental Conditions

Article Preview

Abstract:

The influence of two measuring conditions, the elapsed time after indentation and the condition of edge of an indenter, on the indentation fracture toughness of silicon nitrides was assessed. No slow crack-growth after unloading was confirmed by optical microscopic observation of a crack tip induced by the indentation, which led to the negligible difference in fracture toughness measured at 1 and 30 min after the indentation. Measurements with relatively new and used indenters gave almost the same fracture toughness data, indicating that the crack lengths were hardly affected by the slight damage of the corner of the indenter. It was suggested that the large scattering of the indentation fracture toughness reported by the round-robin tests such as VAMAS was not originated from these factors.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

45-48

Citation:

Online since:

August 2007

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2007 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] B.R. Lawn, A.G. Evans and D.B. Marshall: J. Am. Ceram. Soc. Vol. 64 (1981), p.539.

Google Scholar

[2] H. Awaji, T. Yamada and H. Okuda: J. Ceram. Soc. Jpn. Vol. 99 (1991), p.417.

Google Scholar

[3] Report of preliminary investigation for standardization of fine ceramics, Japanese Fine Ceramics Association (1998).

Google Scholar

[4] C.B. Ponton and R.D. Rawlings: Mater. Sci. Tech. Vol. 5 (1989), p.961.

Google Scholar

[5] T. Miyoshi, N. Sagawa and T. Sasa: J. Jpn. Soc. Mech. Eng. A Vo. 51 (1985), p.2489.

Google Scholar

[6] K. Niihara, R. Morena and D.P.H. Hasselman: J. Mater. Sci. Lett. Vol. 1 (1982), p.13.

Google Scholar

[7] K.D. McHenry, T. Yonushonis and R.E. Tressler: J. Am. Ceram. Soc. Vol. 59 (1976), p.262.

Google Scholar

[8] A. Bhatnagar, M.J. Hoffman and R.H. Dauskardt: J. Am. Ceram. Soc. Vol. 83 (2000), p.585 Fig. 3 SEM micrographs of the corner of the indenter. (a): relatively new indenter and (b): used one. (a) (b) 2µm 2µm.

Google Scholar