What is Terfenol-D?
Terfenol-D is an alloy of terbium, dysprosium, and iron metals and has the largest room
temperature magnetostriction of any known material.
The name Terfenol-D comes from the metallic elements; terbium (TER), iron (FE), Naval
Ordnance Labs (NOL), and Dysprosium (-D). NOL developed and named the material, and
is now known as Naval Surface Warfare Center - Carderock Division (NSWC-CD). The Navy
developed Terfenol-D for higher power sonar that would also have greater bandwidth and
greater reliability. ETREMA holds patents and licenses to many Terfenol-D applications,
including the exclusive worldwide licenses to manufacture all types of Terfenol-D materials.
In technical terms, Terfenol-D is a solid-state transducer capable of converting very
high energy levels from one form to another. In the case of electrical-to-mechanical
conversion, the magnetostriction of the material generates strains 100 times greater
than traditional magnetostrictives, and 2-5 times greater than traditional piezoceramics.
The material has a high Curie temperature (380 C), which enables magnetostrictive
performance greater than 1000 ppm from room temperature to 200 C. By adjusting the
stoichiometry of the alloy, this temperature range can be extended down to cryogenic