Terfenol-D
Encyclopedia
Terfenol-D, an alloy
of the formula x1-x (x ~ 0.3) is a magnetostrictive material. It was initially developed in the 1970s by the Naval Ordnance Laboratory
in North America. The technology for manufacturing the material efficiently was developed in the 1980s at Ames Laboratory
under a U.S. Navy funded program. It is named after terbium
, iron
(Fe), Naval Ordnance Laboratory
(NOL), and the D comes from dysprosium
.
The alloy has the highest magnetostriction
of any alloy
, up to 0.002 m/m at saturation; it expands and contracts in a magnetic field. Its initial application was in naval sonar
systems. It sees application in magnetomechanical sensors, actuator
s, and acoustic and ultrasonic
transducer
s, e.g. in the SoundBug
device (its first commercial application by FeONIC
). It has also been considered for use in fuel injectors for diesel engine
s because of the high stresses that can be produced.
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
of the formula x1-x (x ~ 0.3) is a magnetostrictive material. It was initially developed in the 1970s by the Naval Ordnance Laboratory
Naval Ordnance Laboratory
The Naval Ordnance Laboratory , now disestablished, formerly located in White Oak, Maryland was the site of considerable work that had practical impact upon world technology. The White Oak site of NOL has now been taken over by the Food and Drug Administration.-History:The U.S...
in North America. The technology for manufacturing the material efficiently was developed in the 1980s at Ames Laboratory
Ames Laboratory
Ames Laboratory is a United States Department of Energy national laboratory located in Ames, Iowa. The Laboratory conducts research into various areas of national concern, including the synthesis and study of new materials, energy resources, high-speed computer design, and environmental cleanup...
under a U.S. Navy funded program. It is named after terbium
Terbium
Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife...
, iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
(Fe), Naval Ordnance Laboratory
Naval Ordnance Laboratory
The Naval Ordnance Laboratory , now disestablished, formerly located in White Oak, Maryland was the site of considerable work that had practical impact upon world technology. The White Oak site of NOL has now been taken over by the Food and Drug Administration.-History:The U.S...
(NOL), and the D comes from dysprosium
Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime...
.
The alloy has the highest magnetostriction
Magnetostriction
Magnetostriction is a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of material's magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ...
of any alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
, up to 0.002 m/m at saturation; it expands and contracts in a magnetic field. Its initial application was in naval sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
systems. It sees application in magnetomechanical sensors, actuator
Actuator
An actuator is a type of motor for moving or controlling a mechanism or system. It is operated by a source of energy, usually in the form of an electric current, hydraulic fluid pressure or pneumatic pressure, and converts that energy into some kind of motion. An actuator is the mechanism by which...
s, and acoustic and ultrasonic
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
transducer
Transducer
A transducer is a device that converts one type of energy to another. Energy types include electrical, mechanical, electromagnetic , chemical, acoustic or thermal energy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a...
s, e.g. in the SoundBug
SoundBug
Soundbug is a small speaker that can turn a resonant flat surface into a flat panel speaker. The Soundbug is attached to a smooth resonant surface, this surface then acts as speaker. The tone differs depending on the surface...
device (its first commercial application by FeONIC
FeONIC
FeONIC is a commercial company specialising in the design and development of Magnetostrictive Audio products as a spin off from Hull University.- Technology :...
). It has also been considered for use in fuel injectors for diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s because of the high stresses that can be produced.