Ultrasonic measurements of Young's modulus and extensional wave attenuation in refractory metal wires at elevated temperatures with application to ultrasonic thermometry

Autor:	L. C. Lynnworth, A. Robertson, K. A. Fowler, E. P. Papadakis, E. D. Zysk
Rok vydání:	1974
Předmět:	Absorption (acoustics) Materials science Attenuation Metallurgy Refractory metals General Physics and Astronomy Young's modulus symbols.namesake Melting point symbols Ultrasonic sensor Grain boundary Composite material Elastic modulus
Zdroj:	Journal of Applied Physics. 45:2409-2420
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.1663607
Popis:	Ultrasonic velocity and attenuation measurements have been made by traveling‐wave methods on several refractory metals and their alloys. Broad‐band pulses centered around 120 kHz were used for extensional waves (and some torsional waves) in wire specimens. Elastic moduli calculated from the velocities decrease with increasing temperature; the slope increases in magnitude at about half the absolute melting point. At the same point, the attenuation begins to increase rapidly and peaks 300–600°C above the breakpoint. These effects are ascribed to absorption in grain boundaries. The transit time versus temperature in rhenium wire has been calibrated for the use of rhenium as an ultrasonic thermometer sensor. Ultrasonic thermometry above 2000°C is an application of the present measurements.
Databáze:	OpenAIRE
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