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Non-contact Ultrasonic Treatment of Metals In a Magnetic Field

by John B Wilgen, Roger A Kisner, Roger A Jaramillo, Gerard M Ludtka, Gail M Ludtka
Publication Type
Conference Paper
Publication Date
Page Numbers
145 to 150
Conference Name
TMS 2007 Annual Meeting (The Minerals, Metals & Materials Society)
Conference Location
Orlando, Florida, United States of America
Conference Date

A high-field EMAT (Electromagnetic Acoustical Transducer) has been used for non-contact ultrasonic processing of aluminum samples during solidification. The magnetic field for the EMAT is supplied by a high-field (20 Tesla) resistive magnet, and the current is provided by an induction coil. This resulted in a highly efficient EMAT that delivered 0.5 MPa of acoustic drive to the surface of the sample while coupling less than 100 watts of incidental induction heating. The exceptionally high energy efficiency of the electromagnetic transducer is due to the use of high magnetic field, which reduces the current needed to achieve the same acoustic pressure. In the initial experiments, aluminum samples of A356 alloy were heated to the liquid state and allowed to solidify at a controlled cooling rate while subjected to the non-contact ultrasonic stimulation (0.5 MPa @ 165 kHz) provided by an induction coil located within the bore of a 20-T resistive magnet