Terfenol-D

Two laminated pieces of Terfenol-D, one containing a drilled hole.

Terfenol-D is an alloy comprised of Terbium, Dysprosium and Iron. Terfenol-D has the largest room temperature magnetostriction of any known material. Terfenol-D is a solid-state material capable of converting energy from one form to another. In the case of electrical-to-mechanical conversion, the magnetostriction of the Terfenol-D 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. Adjustments in alloy composition can extend this range down to cryogenic temperatures.

The name Terfenol originated from the metallic elements, Terbium (TER) and Iron (FE); and the discovering organization, Naval Ordnance Laboratory (NOL). Dysprosium (-D) was added as an alloying addition later to reduce the magnetic fields required to induce the magnetostrictive response. NOL, now known as the Naval Surface Warfare Center – Carderock Division (NSWCCD) developed Terfenol-D for high power sonar offering greater bandwidth and reliability over legacy technologies. TdVib holds key patents and licenses for many Terfenol-D applications, including exclusive worldwide licenses to manufacture several types of Terfenol-D materials. TdVib is the world’s leading supplier of Terfenol-D materials and products. Additionally, TdVib provides assistance with the design and manufacturing of Terfenol-D driven products.

Physical Properties

Terfenol-D’s physical properties are provided in the table. Terfenol-D exhibits a large magnetostrictive and magnetic flux density response versus applied magnetic field over a large range of compressive stresses. The following graphs are representative of Terfenol-D produced by TdVib.

Magnetostriction

Magnetic Flux Density

In addition, TdVib can tailor the Terfenol-D composition to allow for a wider operating temperature range. By adjusting the Tb:Dy ratio large magnetostriction values can be achieved at temperatures as low as -200°C and as high as 200°C.

Terfenol-D Thermal Response

TdVib provides Terfenol-D ready-to-use, lowering the effective cost to our customers. TdVib’s patented crystal growing machines produce solid metallic rods. Customer specific geometries are produced by our unique machining processes. Typical Terfenol-D shapes and sizes are provided below.

Available Terfenol-D Shapes and Sizes

Solid Rods

Diameters up to 68mm with maximum length of 280mm or less.
We typically stock rods of diameters 10, 13, 16, 20, 26, 30, 40, 50, 65 and 68mm.

Laminated Rods

Laminated rods are used for eddy current control in higher frequency applications. TdVib will recommend a lamination thickness based on the operating frequency of your application.
Minimum lamination thickness available for Terfenol-D is 0.030 inch.

Square Cross-Section

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For smaller sizes and in large quantities, square cross sections are often more cost effective than round cross-sections.
2mm square, 3mm square and 4mm square rods are common sizes produced by TdVib.

Holes and Custom Shapes

Solid and laminated rods are frequently produced with axial holes to facilitate active cooling or prestress application.
Holes can also be produced in plates and other shapes.
Non-routine shapes are frequently produced with the axis of maximum magnetostriction in preferred orientations.

Terfenol-D Powder

Terfenol-D powder is increasingly used for applications such as sensors and composite materials.
Powder is available in the following various mesh sizes:

Powder Size (microns)
0-300
250-300
106-300
106-250
38-106
0-38

Have questions or want a quotation?

Contact TdVib for a quotation on the quantity and configuration needed. Or work with us to optimize performance and cost for your application

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