Use of ultrasonic signal analysis in the detection of deformation-induced cavitation

A correlation between the change in ultrasonic wave forms and increasing strain in an aluminum alloy, 6061-T6, has been obtained at high strain levels. Sophisticated signal-processing techniques have revealed a complex interaction of the frequency components of a high-frequency ultrasonic pulse as it passes through a deformed tensile specimen. It is believed that strain-induced microstructural changes in the aluminum attenuate the acoustic energy. One of the possible attenuation mechanisms is the formation of deformation induced cavities at precipitates and inclusions which scatter the ultrasonic energy. Thus, measuring the signal attention at the appropriate frequencies determines the degree of deformation-induced cavitation