Magnetostrictive materials and ultrasonics
In the early 1970s a group of Navy scientists led by A.E. Clark began experimenting with highly magnetostrictive rare earth metals, substances that would lengthen in response to a magnetic field. By 1976 the group had discovered an alloy of iron and terbium that exhibited tremendous levels of magnetostriction. They also discovered that, by adding dysprosium, they could lessen the degree of anisotropy in the magnetization of the alloy. Clark named the new material Terfenol-D after terbium, iron, the Naval Ordinance Lab, and dysprosium. Because Terfenol-D was originally developed for sonar applications, it was regarded as usable at low frequencies only from direct current (dc) to 2 kHz. Furthermore, eddy current activity was believed to be so great that high-frequency operation was deemed impractical. However, Terfenol-D can be used into the ultrasonic frequency range. It exhibits the greatest magnetostrictive effects of any commercially available material and is now positioned for a wide range of high-frequency uses--in which piezoceramic materials were formerly used exclusively. The authors have harnessed the energy efficiency of this alloy and discuss the use of this material in actuators.
- OSTI ID:
- 367902
- Journal Information:
- CHEMTECH, Journal Name: CHEMTECH Journal Issue: 8 Vol. 26; ISSN CHTEDD; ISSN 0009-2703
- Country of Publication:
- United States
- Language:
- English
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