Photothermal Length Measurement of Vickers Cracks in SI3N4
Ceramic materials are gaining ever increasing popularity in different high—technology applications, especially in those where high temperatures are used. However, the mechanical strength of ceramics has thus far set limitations on their utilizing. The critical size of cracks in ceramic material depends on the force applied, but in typical applications it is less than 100 µm. This small size in addition to the fact that critical cracks are often closed makes the use of conventional NDT methods in crack detection very difficult or even impossible. More nuisance comes from the porosity of the material which takes methods needing immersing in liquids out of consideration.
KeywordsCrack Length Effective Thermal Conductivity Probe Beam Critical Crack Thermal Contact Resistance
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- 1.L. J. Inglehart: Optical Beam Deflection Detection of Thermal Waves in Opaque Solids, Dissertation, Wayne State University, Detroit, Mich. (1984)Google Scholar
- 3.L. J. Inglehart, M. J. Lin, L. D. Favro, P. K. Kuo, R. L. Thomas: In Proc. IEEE Ultrason. Symp., ed. by B. R. McAvey ( Institute of Electrical and Electronic Engineers, New York 1983 ) p. 668Google Scholar
- 4.F. A. McDonald, C. G. Wetsel: In Proc. IEEE Ultrason. Symp., ed. by B. R. McAvey ( Institute of Electrical and Electronic Engineers, New York 1984 ) P. 622Google Scholar
- 5.L. D. Favro, P. K. Kuo, R. L. Thomas: In Photoacoustic and Thermal Wave Phenomena in Semiconductors, ed. by A. Mandelis ( North Holland Publishing, Amsterdam 1987 ) p. 68Google Scholar
- 6.F. A. McDonald, C. G. Wetsel, C. G. Clark: In Proc. IEEE Ultrason. Symp., ed. by B. R. McAvey ( Institute of Electrical and Electronic Engineers, New York 1983 ) p. 672Google Scholar