Low-temperature ultrasonic attenuation in radidly cooled niobium containing oxygen and hydrogen
Measurements of ultrasonic attenuation and velocity in dilute Nb-O-H alloys were made as a function of temperature, frequency, polarization, annealing temperature, isotope, and defect concentration. In addition to the stable 2.5 K relaxation peak found earlier by Poker, et. al., and additional peak at 6.3 K at 10 MHz was found when the specimen was rapidly cooled to He temperature. The peak correlated with the resistivity recovery found by Hanada for quenched specimens and corresponds to a complex with tetragonal symmetry. With the previous resistivity experiments mentioned above and the ultrasonic results described here, it can be concluded that peak 2 at 6.3 K arises from an OH complex. The simplest interpretation is that it represents an OH/sub 2/ complex. In a slow cooling process, one oxygen traps only one hydrogen and this OH pair is rather stable. In a rapid cooling process, some of the oxygen traps more than one hydrogen, forming OH/sub 2/. However, the second hydrogen is less strongly bound than the first. During annealing, detrapping of one of the two hydrogens occurs and an OH/sub 2/ becomes an OH with freed hydrogen going into precipitates.
- Research Organization:
- Illinois Univ., Urbana (USA)
- DOE Contract Number:
- AC02-76ER01198
- OSTI ID:
- 5266260
- Report Number(s):
- DOE/ER/01198-1377; CONF-820325-9; ON: DE82012717
- Country of Publication:
- United States
- Language:
- English
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