ASA 126th Meeting Denver 1993 October 4-8

4aPA8. Elastic constants and damping using ultrasonic resonance spectroscopy: Application to monocrystal and polycrystal copper.

H. Ledbetter C. M. Fortunko

Natl. Inst. of Standards and Technology, 325 Broadway, Boulder, CO 80303

P. Heyliger

Colorado State Univ., Fort Collins, CO 80523

Several authors used ultrasonic resonance spectroscopy to determine a material's elastic-stiffness constants, the Voigt C[sub ij]. Complementary to these are the out-of-phase C[sub ij][sup *], which give the complete elastic stiffness C[sub ij]=C[sub ij]+iC[sub ij][sup *]. Here, C[sub ij][sup *] measurements for both monocrystal and polycrystal copper are reported. For the monocrystal case, the C[sub ij][sup *] vary strongly with the vibrational mode. And, when interpreted against a vibrating-string dislocation model, the C[sub ij][sup *] present several surprises. For the polycrystal, the C[sub ij][sup *] are much lower and nearly independent of vibration mode.