日本金属学会誌

J. Japan Inst. Metals, Vol. 17, No. 8 (1953),
pp. 412-416

The Attenuation of Ultrasonic Waves in Metal (I). Aluminium

Tokutaro Hirone and Kazuo Kamigaki


Abstract:

Attenuation of the ultrasonic waves propagating in aluminium rods under various heat treatments were measured for a wide range of frequency (2-25 mcps). Pulsed longitudinal waves were emitted into the rods and the transmitted pulses were detected by a crystal on the back surface of the specimen. Measurements of the attenuation of the sound waves were carried out by the compensation method using an attenuator at the in-put side of the receiving amplifier. The purity of the specimen used was 99.4%. The specimen was firstly subjected to cold work and then annealed at 600°C for 5, 10, 5 and 25 hours successively. On the basis of these measurements it was found that the decay of transmitted waves was characterized by exponential attenuation. For the specimens of long time annealing, however, patterns of a number of irregular reflections were observed, as will be shown in Photos. 2 and 3. The emergence of such irregular echoes is supposed to be due to the multiple reflections of ultrasonic waves on the grain boundaries rigidly formed by the successive annealing.


(Received 1953/3/2)

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