Investigating Cases of 'Abnormal' Attenuation of Ultrasonic Oscillations in Blanks of Nickel Heat-Resistant Alloys
| Autor: | I. S. Krasnov, M. A. Dalin, V. Yu. Chertishchev, A. N. Raevskikh |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Structural material business.industry Mechanical Engineering Attenuation Drop (liquid) chemistry.chemical_element Condensed Matter Physics 01 natural sciences Signal Nickel Amplitude chemistry Mechanics of Materials Nondestructive testing 0103 physical sciences General Materials Science Ultrasonic sensor Composite material business 010301 acoustics |
| Zdroj: | Russian Journal of Nondestructive Testing. 56:984-994 |
| ISSN: | 1608-3385 1061-8309 |
| DOI: | 10.1134/s1061830920120037 |
| Popis: | During ultrasonic nondestructive testing of several stamped forgings made of nickel heat-resistant alloys of two grades, we discovered a new phenomenon of a local decrease in the amplitude of the bottom echo signal. The decrease was accompanied by the presence of large (more than 20 mm) zones with considerable (up to 1.5%) fluctuations in the propagation velocity of a longitudinal ultrasonic wave that were chaotically scattered over the surface of the semi-finished product. In this case, the material revealed no uneven grain-size distribution or coarse-grained structure, usually causing an increase in the coefficient of attenuation of ultrasonic waves in such alloys and causing a decrease in the amplitude of the bottom echo signal. The present paper describes the studies carried out to establish the physical reasons for the discovered macroscopic inhomogeneity of velocity and its relationship with the drop in the amplitude of the bottom signal. |
| Databáze: | OpenAIRE |
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