Measurement of High‐Temperature Elastic Properties of Ceramics Using a Laser Ultrasonic Method

Abstract

Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP).At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner.

Mechanically induced stiffening, thermally driven softening, and brittle nature of SiC

“…Figure 26 illustrates the Poisson's ratio  as a function of temperature. The Poisson's ratio  is independent of temperature and is consistent with the earlier measured  by laser ultrasonics method [69]. We note that the deduced value of  ≈ 0.174 which is smaller than 0.33, again indicates that SiC is brittle in nature.…”

“…Table 2 at room temperature. Deduced values of wave velocities are in good agreement with the measured values by laser ultrasonics method [69]. The high temperature behavior of aggregate elastic constants and others for SiC can be considered as a predictive study as they cannot be compared due to unavailability of high temperature data.…”

“…It is shown that at T = 273 K, E is about 438 GPa and shows a decreasing behavior with increasing temperature. The calculation presented here leads to a value of about 549 GPa which is comparable to the measured value of 437 GPa at room temperature [69]. Figure 26 illustrates the Poisson's ratio  as a function of temperature.…”

“…A decreasing trend is inferred with increase in temperature. Matsumoto and researchers [69] have reported the Young's modulus and Poisson's ratio of SiC at temperatures > 1400 ℃ using laser ultrasonics coupled with Fabry-Pérot interferometery as well as ultrasonic pulse method. It is shown that at T = 273 K, E is about 438 GPa and shows a decreasing behavior with increasing temperature.…”

Monitoring of Refractory Wall recession using high temperature impact echo instrumentation

“…If conventional transducers are to be used, buffer rod and couplant issues add tremendous complexity to the application. The use of laser-based ultrasound [5] , while expensive, might be justified for critical areas. Aluminum nitride transducers in direct contact with the hot test article will likely be a future alternative.…”