Publication Date:
2014-10-03
Description:
Platinum metal group alloys are promising materials for use in a new generation of gas turbine engines owing to their excellent high-temperature properties. In the present work, room temperature elastic properties of single crystals of Rh 3 Nb and Rh 3 Zr are investigated. Surface Brillouin scattering spectra for a range of wave vector directions on the (001) surface have been acquired in order to determine the angular variation of the velocities of the Rayleigh and pseudo-surface acoustic waves and that of the longitudinal lateral wave (LLW) threshold within the Lamb shoulder. The elastic stiffness constants C 11 , C 12 , and C 44 of these cubic crystal specimens have been derived using two approaches: the first involving the least-squares fit of the combined measured wave velocity data to calculated values and the second an analytical approach using the Rayleigh velocities in the [100] and [110] directions and LLW velocity in the [100] direction, and extracting the elastic stiffness constants from the secular equations for these velocities. Results from the two methods are in good agreement and are for Rh 3 Nb, C 11 = 368 ± 3, C 12 = 186 ± 5, and C 44 = 161 ± 3 in GPa; and for Rh 3 Zr, C 11 = 329 ± 4, C 12 = 185 ± 6, and C 44 = 145 ± 4 in GPa.
Print ISSN:
0021-8979
Electronic ISSN:
1089-7550
Topics:
Physics
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