An approach to assessing ultrasonic attenuation in molten magnesium alloys

Few experimental data are available on ultrasonic attenuation in molten light alloys due to lack of means of characterization. An approach has been proposed and demonstrated to assessing ultrasonic attenuation in molten magnesium alloys based on the finding that the grain density in ultrasonicated magnesium alloy samples depends linearly on ultrasonic amplitude along the propagation direction. Hence, the attenuation of the ultrasonic amplitude with propagation distance can be effectively assessed according to the variations in the grain density with propagation distance. Metallographic analyses revealed that the dependence of grain density on propagation distance is best described exponentially with respect to different amplitudes. Consequently, the attenuation behavior of the ultrasonic amplitude with propagation distance can be described by the same exponential law. The characteristic ultrasonic attenuation coefficients in three benchmark molten magnesium alloys investigated were determined accordingly. The validation experiments confirmed the validity of the data produced. Ultrasonic attenuation shows dependence on alloy chemistry. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3054374]