The ultrasonic measurement of elastic constants of cubic crystals

Author

Madhu Puri

Date of Award

3-1986

Degree Type

Thesis

Degree Name

Master of Science

Major

Physics

Major Professor

M. A. Breazeale

Committee Members

C. C. Shih, J. O. Thomson

Abstract

To evaluate the combination of third-order elastic constants K₃ of cubic crystals, one needs very accurate values of the combination of second-order elastic constants K₂. Often one can obtain numerical values of second-order elastic constants for the sample of interest from existing data. Due to the error propagation and the experimental uncertainties at the time of the original measurement, however, there may be uncertainties in the magnitude of K₂. An alternative way to arrive at K₂'s would be to measure them at the time the K₃ data are taken. This measurement is quite straightforward since K2's are directly related to the sound velocities, which can be measured. The extra time and effort spent in doing the latter would be justified by an increase in accuracy. The purpose of this thesis is to study these alternatives and compare error propagation in an effort to arrive at the most accurate values of K₂. The analysis in this thesis shows that the question originally posed does not have a unique answer for all samples under all conditions. One cannot decide a priori whether the reference values of C_ij should be used or whether one should ' J measure the C_ij each time one measures C_ijk. The analysis given, however, suggests that one should use reference data rather than measuring each sample, if the reference data are as accurate as those of McSkimin. If such accurate data are not available, one has no choice. One must measure the K₂ directly.

Recommended Citation

Puri, Madhu, "The ultrasonic measurement of elastic constants of cubic crystals. " Master's Thesis, University of Tennessee, 1986.
https://trace.tennessee.edu/utk_gradthes/13784