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38-494: FSMA may refer to: Ferromagnetic shape-memory alloy , a type of shape memory material which responds to magnetic fields Financial Services and Markets Act 2000 , a UK law that created the Financial Services Authority Financial Services and Markets Authority , a Belgian government agency Food Safety Modernization Act , a U.S. law that expands

76-475: A H 2 S atmosphere. Thus, single-crystal-like texture (~90% {011} grain coverage) is attainable, reducing the interference with magnetic domain alignment and increasing microstrain attainable for polycrystalline alloys as measured by semiconducting strain gauges . These surface textures can be visualized using electron backscatter diffraction (EBSD) or related diffraction techniques. For actuator applications, maximum rotation of magnetic moments leads to

114-405: A change in the material's dimensions is a consequence of magnetocrystalline anisotropy ; it takes more energy to magnetize a crystalline material in one direction than in another. If a magnetic field is applied to the material at an angle to an easy axis of magnetization, the material will tend to rearrange its structure so that an easy axis is aligned with the field to minimize the free energy of

152-410: A changing magnetic field. Internally, ferromagnetic materials have a structure that is divided into domains , each of which is a region of uniform magnetization. When a magnetic field is applied, the boundaries between the domains shift and the domains rotate; both of these effects cause a change in the material's dimensions. The reason that a change in the magnetic domains of a material results in

190-428: A different orientation of the elementary cells (the regions are shown by the figure in green and blue colors). These regions are called twin-variants. The application of a magnetic field or of an external stress shifts the boundaries of the variants, called twin boundaries , and thus favors one variant or the other. When the element is completely contracted or completely elongated, it is formed by only one variant and it

228-455: A helical anisotropy of the susceptibility of a magnetostrictive material when subjected to a torque and the Wiedemann effect is the twisting of these materials when a helical magnetic field is applied to them. The Villari reversal is the change in sign of the magnetostriction of iron from positive to negative when exposed to magnetic fields of approximately 40  kA/m . On magnetization,

266-512: A low magnetic-anisotropy field strength, H A , of less than 1 kA/m (to reach magnetic saturation ). Metglas 2605SC also exhibits a very strong ΔE-effect with reductions in the effective Young's modulus up to about 80% in bulk. This helps build energy-efficient magnetic MEMS . Cobalt ferrite , CoFe 2 O 4 (CoO·Fe 2 O 3 ), is also mainly used for its magnetostrictive applications like sensors and actuators, thanks to its high saturation magnetostriction (~200 parts per million). In

304-529: A lower internal friction, a higher transformation temperature and a higher Curie temperature, which would allow the use of MSM alloys in several applications. In fact, the actual temperature range of standard alloys is up to 50 °C. Recently, an 80 °C alloy has been presented. Due to the twin boundary motion mechanism required for the magnetic shape memory effect to occur, the highest performing MSMAs in terms of maximum induced strain have been single crystals. Additive manufacturing has been demonstrated as

342-548: A magnetic material undergoes changes in volume which are small: of the order 10 . Like flux density , the magnetostriction also exhibits hysteresis versus the strength of the magnetizing field. The shape of this hysteresis loop (called "dragonfly loop") can be reproduced using the Jiles-Atherton model . Magnetostrictive materials can convert magnetic energy into kinetic energy , or the reverse, and are used to build actuators and sensors . The property can be quantified by

380-622: A pure element at 60 microstrains . Among alloys, the highest known magnetostriction is exhibited by Terfenol-D , (Ter for terbium , Fe for iron , NOL for Naval Ordnance Laboratory , and D for dysprosium ). Terfenol-D, Tb x Dy 1− x Fe 2 , exhibits about 2,000 microstrains in a field of 160 kA/m (2 kOe) at room temperature and is the most commonly used engineering magnetostrictive material. Galfenol , Fe x Ga 1− x , and Alfer , Fe x Al 1− x , are newer alloys that exhibit 200-400 microstrains at lower applied fields (~200 Oe) and have enhanced mechanical properties from

418-485: A technique to produce porous polycrystalline MSMAs. As opposed to fully dense polycrystalline MSMAs, porous structures allow more freedom of motion, which reduces the internal stress required to activate martensitic twin boundary motion. Additionally, post-process heat treatments such as sintering and annealing have been found to significantly increase the hardness and reduce the elastic moduli of Ni-Mn-Ga alloys. MSM actuator elements can be used where fast and precise motion

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456-489: Is a function of strain. The most common MSM actuator design consists of an MSM element controlled by permanent magnets producing a rotating magnetic field and a spring restoring a mechanical force during the shape memory cycling. Limitations on the magnetic shape memory effect due to crystal defects determine the efficiency of MSMAs in applications. Since the MSM effect is also temperature dependent, these alloys can be tailored to shift

494-469: Is different from Wikidata All article disambiguation pages All disambiguation pages Ferromagnetic shape-memory alloy MSM alloys are ferromagnetic materials that can produce motion and forces under moderate magnetic fields. Typically, MSMAs are alloys of Nickel, Manganese and Gallium (Ni-Mn-Ga). A magnetically induced deformation of about 0.2% was presented in 1996 by Dr. Kari Ullakko and co-workers at MIT. Since then, improvements on

532-430: Is hypothesized to be due to a "jump" in initial alignment of domains perpendicular to applied stress and improved final alignment parallel to applied stress. These materials generally show non-linear behavior with a change in applied magnetic field or stress. For small magnetic fields, linear piezomagnetic constitutive behavior is enough. Non-linear magnetic behavior is captured using a classical macroscopic model such as

570-437: Is obtained by the geometric rotation of the elementary cells composing the alloy, and not by rotation of the magnetization vectors within the cells (like in magnetostriction ). A similar phenomenon occurs when the alloy is subjected to an external force. Macroscopically, the force acts like the magnetic field, favoring the rotation of the elementary cells and achieving elongation or contraction depending on its application within

608-550: Is required. They are of interest due to the faster actuation using magnetic field as compared to the heating/cooling cycles required for conventional shape memory alloys, which also promises higher fatigue lifetime. Possible application fields are robotics, manufacturing, medical surgery, valves, dampers, sorting. MSMAs have been of particular interest in the application of actuators (i.e. microfluidic pumps for lab-on-a-chip devices) since they are capable of large force and stroke outputs in relatively small spatial regions. Also, due to

646-404: Is said to be in a single variant state . The magnetization of the MSM element along a fixed direction differs if the element is in the contraction or in the elongation single variant state. The magnetic anisotropy is the difference between the energy required to magnetize the element in contraction single variant state and in elongation single variant state. The value of the anisotropy is related to

684-433: The ingot . For a polycrystalline alloy, an established formula for the magnetostriction, λ, from known directional microstrain measurements is: λ s = 1/5(2λ 100 +3λ 111 ) During subsequent hot rolling and recrystallization steps, particle strengthening occurs in which the particles introduce a “pinning” force at grain boundaries that hinders normal ( stochastic ) grain growth in an annealing step assisted by

722-469: The absence of rare-earth elements, it is a good substitute for Terfenol-D . Moreover, its magnetostrictive properties can be tuned by inducing a magnetic uniaxial anisotropy. This can be done by magnetic annealing, magnetic field assisted compaction, or reaction under uniaxial pressure. This last solution has the advantage of being ultrafast (20 min), thanks to the use of spark plasma sintering . In early sonar transducers during World War II, nickel

760-403: The alloy goes to the austenite phase where the elementary cells have cubic geometry. With such geometry the magnetic shape memory effect is lost. The transition from martensite to austenite produces force and deformation. Therefore, MSM alloys can be also activated thermally, like thermal shape memory alloys (see, for instance, Nickel-Titanium ( Ni-Ti ) alloys). The mechanism responsible for

798-645: The authority of the Food and Drug Administration Marie Louise Island Airport 's ICAO code Optical fiber connector of type F-SMA (fiber sub-miniature assembly) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title FSMA . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=FSMA&oldid=1218606975 " Category : Disambiguation pages Hidden categories: Short description

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836-466: The brittle Terfenol-D. Both of these alloys have <100> easy axes for magnetostriction and demonstrate sufficient ductility for sensor and actuator applications. Another very common magnetostrictive composite is the amorphous alloy Fe 81 Si 3.5 B 13.5 C 2 with its trade name Metglas 2605SC. Favourable properties of this material are its high saturation-magnetostriction constant, λ, of about 20 microstrains and more, coupled with

874-486: The crystal structure and twin boundaries. Additionally, inducing a fully strained (elongated or contracted) MSMA has been found to reduce fatigue life, so this must be taken into consideration when designing functional MSMA systems. In general, reducing defects such as surface roughness that cause stress concentration can increase the fatigue life and fracture resistance of MSMAs. Standard alloys are Nickel - Manganese - Gallium (Ni-Mn-Ga) alloys, which are investigated since

912-447: The deformation. This companion effect, which co-exist with the actuation, can be useful for the design of displacement, speed or force sensors and mechanical energy harvesters . The magnetic shape memory effect occurs in the low temperature martensite phase of the alloy, where the elementary cells composing the alloy have tetragonal geometry. If the temperature is increased beyond the martensite– austenite transformation temperature,

950-476: The first relevant MSM effect has been published in 1996. Other alloys under investigation are Iron - Palladium (Fe-Pd) alloys, Nickel-Iron-Gallium (Ni-Fe-Ga) alloys, and several derivates of the basic Ni-Mn-Ga alloy which further contain Iron (Fe), Cobalt (Co) or Copper (Cu). The main motivation behind the continuous development and testing of new alloys is to achieve improved thermo-magneto-mechanical properties, such as

988-420: The high fatigue life and their ability to produce electromotive forces from a magnetic flux, MSMAs are of interest in energy harvesting applications. The twinning stress, or internal frictional stress, of an MSMA determines the efficiency of actuation, so the operation design of MSM actuators is based on the mechanical and magnetic properties of a given alloy; for example, the magnetic permeability of an MSMA

1026-454: The highest possible magnetostriction output. This can be achieved by processing techniques such as stress annealing and field annealing. However, mechanical pre-stresses can also be applied to thin sheets to induce alignment perpendicular to actuation as long as the stress is below the buckling limit. For example, it has been demonstrated that applied compressive pre-stress of up to ~50 MPa can result in an increase of magnetostriction by ~90%. This

1064-412: The large strain of MSM alloys is the so-called magnetically induced reorientation (MIR), and is sketched in the figure. Like other ferromagnetic materials, MSM alloys exhibit a macroscopic magnetization when subjected to an external magnetic field, emerging from the alignment of elementary magnetizations along the field direction. However, differently from standard ferromagnetic materials, the alignment

1102-424: The magnetostrictive coefficient, λ, which may be positive or negative and is defined as the fractional change in length as the magnetization of the material increases from zero to the saturation value. The effect is responsible for the familiar " electric hum " ( Listen ) which can be heard near transformers and high power electrical devices. Cobalt exhibits the largest room-temperature magnetostriction of

1140-432: The maximum work-output of the MSM alloy, and thus to the available strain and force that can be used for applications. The main properties of the MSM effect for commercially available elements are summarized in (where other aspects of the technology and of the related applications are described): The fatigue life of MSMAs is of particular interest for actuation applications due to the high frequency cycling, so improving

1178-447: The mechanical properties ( ductility ) of magnetostrictive alloys can be significantly improved. Targeted metallurgical processing steps promote abnormal grain growth of {011} grains in galfenol and alfenol thin sheets, which contain two easy axes for magnetic domain alignment during magnetostriction. This can be accomplished by adding particles such as boride species and niobium carbide ( NbC ) during initial chill casting of

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1216-402: The microstructure of these alloys has been of particular interest. Researchers have improved the fatigue life up to 2x10 cycles with a maximum stress of 2MPa, providing promising data to support real application of MSMAs in devices. Although high fatigue life has been demonstrated, this property has been found to be controlled by the internal twinning stress in the material, which is dependent on

1254-584: The production process and on the subsequent treatment of the alloys have led to deformations of up to 6% for commercially available single crystalline Ni-Mn-Ga MSM elements, as well as up to 10-12 % and 20% for new alloys in R&;D stage. The large magnetically induced strain, as well as the short response times make the MSM technology very attractive for the design of innovative actuators to be used in pneumatics, robotics, medical devices and mechatronics. MSM alloys change their magnetic properties depending on

1292-410: The reference coordinate system. The elongation and contraction processes are shown in the figure where, for example, the elongation is achieved magnetically and the contraction mechanically. The rotation of the cells is a consequence of the large magnetic anisotropy of MSM alloys, and the high mobility of the internal regions. Simply speaking, an MSM element is composed by internal regions, each having

1330-511: The system. Since different crystal directions are associated with different lengths, this effect induces a strain in the material. The reciprocal effect, the change of the magnetic susceptibility (response to an applied field) of a material when subjected to a mechanical stress, is called the Villari effect . Two other effects are related to magnetostriction: the Matteucci effect is the creation of

1368-415: The transition temperature by controlling microstructure and composition. Magnetostriction Magnetostriction is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization . The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. The effect

1406-418: Was first identified in 1842 by James Joule when observing a sample of iron . Magnetostriction applies to magnetic fields, while electrostriction applies to electric fields. Magnetostriction causes energy loss due to frictional heating in susceptible ferromagnetic cores, and is also responsible for the low-pitched humming sound that can be heard coming from transformers, where alternating currents produce

1444-522: Was used as a magnetostrictive material. To alleviate the shortage of nickel, the Japanese navy used an iron - aluminium alloy from the Alperm family. Single-crystal alloys exhibit superior microstrain, but are vulnerable to yielding due to the anisotropic mechanical properties of most metals. It has been observed that for polycrystalline alloys with a high area coverage of preferential grains for microstrain,

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