Actuating element with a magnetic shape memory alloy and method for producing the same

Abstract

The present invention relates to an operating element and a method for manufacturing an operating element having a magnetic shape memory alloy. In this method, at least a part of the magnetic shape memory alloy is provided as an active region (1, 2) responsive to a magnetic field, and at least one other part of the magnetic shape memory alloy is provided as an inactive region (3) unresponsive to the magnetic field.

Description

Technical Field

[0001] The present invention relates to an operating element and a method for manufacturing an operating element.

[0002] The operating element according to the present invention comprises a magnetic shape memory alloy material and is intended to be used as an operating or functional element of various devices and equipment. Certain regions in the operating element can be activated by the magnetic shape memory (MSM) effect, which is defined herein as the active region; while other regions are made inactive by a special manufacturing method so that these inactive regions do not deform in the applied magnetic field, but they have other essential functions of the device. The inactive regions can be used as the housing of the device, springs, magnetic flux paths, grippers, valves, optical or electrical switches, fluid cavities or channels or parts thereof. The present invention is a solution in which a local magnetic field is used to produce local changes in the twin variant structure on the magnetic shape memory material, so that the elements therein can be locally constrained. The operating element can be made of Ni-Mn-Ga or Ni-Mn-Ga-based alloys that currently exhibit the best magnetic shape memory properties. The present invention will simplify the complex devices of various industrial equipment, such as the optical, fluid, micro-engineering and biomedical industries. Since multiple functional components included in the entire device or the operating part of the device can be made from a single source element containing magnetic shape memory material, the present invention is particularly important in micron and nanoscale device applications. Background Art

[0003] Magnetic shape memory (MSM) alloys or ferromagnetic shape memory (FSMA) alloys are unique materials that exhibit deformations on the order of a few percent when a magnetic field is applied to them. The deformations produced in samples made of magnetic shape memory alloys are based on magnetic field induction and correspond to the proportion of twin variants in the sample. The main component of magnetic shape memory materials is the Ni-Mn-Ga alloy. Magnetic shape memory materials contain at least two twin variants, which are separated by twin boundaries. The material must have a sufficiently high magnetocrystalline anisotropy energy and a low twin stress so that when an external magnetic field of sufficient strength and direction is applied to the material, the easy magnetization direction and the crystal axis of the material can change with the change of the magnetic field. The material must contain two crystal directions with lattice parameters a and c, and the axis c is the shorter axis. For example, such a material is the 10M martensite of Ni-Mn-Ga. In this example, the c-axis is the direction in which the material is easily magnetized. The plane in which the magnetization direction switches is hereinafter referred to as the active plane. The ratio of the volume of a twin variant to the volume of the entire material is defined as the volume fraction of the said twin variant. The present invention is not limited to Ni-Mn-Ga alloys or other Heusler alloys. The types of twin variants can vary according to the material. When the crystal is, for example, monoclinic, orthorhombic or tetragonal, the types of twin variants in the material can also be different, such as type I and type II twins. These twin variants have different properties, such as the twin stress and the required magnetic field energy for switching between twin variants. Hereinafter, a magnetic shape memory alloy or an MSM alloy is defined as a material in which the magnetic shape memory effect occurs, that is, its shape can be changed by applying a magnetic field of sufficient strength and a suitable direction thereto.

[0004] Magnetic shape memory materials have great commercial potential due to their ability to generate deformations quickly and precisely from an energy source that is not connected to the material. Due to the lack of a suitable active technology that can produce large strokes in micro- and nano-scale devices, magnetic shape memory devices show great commercial potential in micro- and nano-scale device applications. Rotary and linear motors cannot be scaled down to the micro-size level, and the strokes produced by piezoelectric or magnetostrictive materials are very small, only about one percent of the maximum stroke of magnetic shape memory materials made of Ni-Mn-Ga alloys. The efficiency of the magnetic shape memory effect (mechanical work output / magnetic field energy) can exceed 95%, and the fatigue life exceeds 2 billion cycles. Recently, it has been shown that when the driving speed in Ni-Mn-Ga is 4 m / s and the acceleration exceeds one million m / s², this is considered to be the highest acceleration among all driver materials. Since the driving speed and acceleration are mainly limited by the inertia of the moving part of the magnetic shape memory element, small magnetic shape memory devices can benefit the most from high driving speeds and high accelerations. Larger magnetic shape memory devices are slower than smaller ones.

[0005] Current magnetic shape memory devices can include multiple independent functional components, such as a magnetic field path (yoke), springs, a housing, and multiple operating components such as grippers, clamps, valves, electrical switches, etc. Assembling all these components in small batches is a difficult and expensive process, and sometimes it is simply impossible to achieve. It is also very difficult to prepare a suitable twin structure in a tiny magnetic shape memory sample and precisely assemble these elements into a microdevice. The present invention solves the above problems. According to the present invention, the entire device or the operating elements of the device can be made from a single alloy source, i.e., a magnetic shape memory material. The manufactured device includes one or more active regions and may also include some other functional components, such as a housing, a magnetic flux path, springs, and some operating components such as grippers, clamps, or switches. The present invention will simplify many devices in various industrial applications by replacing the independent functional components of current complex machinery. Summary of the Invention

[0006] The present invention includes a method for constructing twin variants and relates to an operating element made of a magnetic shape memory material, wherein a magnetic field is applied to at least one region of a device configured with twin variants. In this region, also known as the active region or the region responsive to the magnetic field of the device, the shape of this region changes due to the applied magnetic field. The other regions of the device can be processed or manufactured in such a way that the magnetic shape memory effect does not occur in those regions, i.e., the shape of those regions does not change due to the applied magnetic field. These non-active regions or regions non-responsive to the magnetic field of the device can be used as springs, magnetic flux paths, machine housings, or other functional components, such as grippers, clamps, manipulators, ejectors, mixers, pumps, valves, manifolds, electrical or optical switches. The local magnetic field applied to the active region or partially active region can be generated by, for example, at least one electromagnet or at least one permanent magnet. By replacing complex mechanical devices, the present invention will simplify many devices in various industrial applications. Examples of application fields include optics, electronics, fluidics, microengineering, and biomedicine. The non-active regions can be made by using special surface treatments or coating a sufficiently hard substance on the surface and other methods. This non-active region can also be made by pressing or clamping methods.

[0007] Before manufacturing an operating element from a source piece of magnetically shape - memory material, a predetermined volume fraction of twin variants can be generated in the source piece of magnetically shape - memory material by mechanical force or a magnetic field. Then, the operating element is made from the source piece of magnetically shape - memory material. Then, those regions in the operating element that are to be made inactive are processed in such a way that when a magnetic field is applied to these regions, the twin boundaries do not move. A local magnetic field with a high enough magnetic - field energy that can change the twin - variant structure in the active regions of the operating element can be used to modify the local structure of the twin variants in the active regions while maintaining the overall volume fraction of the twin variants in the active regions. The active regions can be further restricted between two parallel plates to produce a special twin structure called contraction, as shown below. The device can be manufactured from a thin film by lithography, laser cutting or engraving, or other methods. Description of the Drawings

[0008] Figure 1 Schematically shows an example of a device made of magnetically shape - memory material. Certain regions (3) of the plate are made inactive, which are shown in black. The active regions of the plates (1 and 2) are shown in gray. Figure 1 a shows the case where the crystal axis c is in the horizontal direction. In this case, the active region is short in the axial direction and the gripper is closed. Figure 1 b shows the case where the long crystal axis a is in the axial direction and the short axis c is perpendicular to the axial direction. In this case, the active region is long in the horizontal direction and the gripper is open.

[0009] Figure 2 Schematically shows a plate made of magnetically shape - memory material, where the material serves as a magnetic - flux path induced by an external magnetic - field source (6). The twin variants are denoted by 1 and 2; the inactive regions (black) of the plate are denoted by 3 and 5; the air gap is denoted by 4; the magnetic - flux lines are denoted by 7.

[0010] Figure 3 Schematically shows a top view of a plate made of magnetically shape - memory material. The alloy source piece is stretched so as to obtain the required volume fraction of twin variant 1 and twin variant 2. The surrounding regions (black region 3) of the active region composed of twin variant 1 and 2 are made inactive. The active region of the plate is restricted to the left and right sides of the element. Figure 3 a, 3b and 3c show various configurations of twin variants in the active regions with equal volume fractions of twin variants.

[0011] Figure 4A top view of a plate made of a magnetic shape memory material is schematically shown. The plate has twin variants 1 and 2 with a predetermined volume fraction. The plate is stretched to produce the required volume fractions of twin variant 1 and twin variant 2. After stretching, the surrounding area (black area 3) of the element becomes inactive. Component 5 also becomes inactive. Figure 4 a shows the case where the right side of the active area of the plate shrinks because it consists of variant 2 and the axis c is horizontal along the plate surface. The left side of the active area of the plate is elongated because it contains a wide area (gray) of variant 1 whose crystallographic major axis a is along the plate. Figure 4 b shows how to change the variant structure by using a local magnetic field aligned in the active plane and perpendicular to the horizontal direction of the element. Accordingly, part 5 moves from right to left.

[0012] Figure 5 A plate made of a magnetic shape memory material is schematically shown, in which two slits (4) are cut ( Figure 5 a). The plate is stretched to obtain the desired volume fraction of twin variants ( Figure 5 b). The twin boundaries between the variants are denoted by 8. When the axis c is perpendicular to the drawing plane, the short crystallographic axis c of the variant is marked with a cross surrounded by a small circle in variant 2 (2), while when the axis c points in the horizontal direction of the drawing plane, it is marked with a short horizontal line. Figure 5 c shows the case where the sides of the plate are made inactive (black area 3).

[0013] Figure 6 A plate made of a magnetic shape memory material is schematically shown, in which two slits (4) are cut. The plate is stretched to produce the desired volume fraction of twin variants. The sides of the plate are made inactive (black area 6). The twin boundaries between the variants are denoted by 8. In variants 1 and 2, the short crystallographic axis c is marked with a short line.

[0014] Figure 7 Three snapshots are shown when the center line A - A and the inactive component 5 move to the right. Figure 7 a shows the initial state, Figure 7 b shows the intermediate state, Figure 7 c shows the final state, where the active area on the left side of component 5 is in a single variant state with the axis c in the vertical direction, while the active area on the right side of component 5 is in a single variant state with the axis c in the horizontal direction.

[0015] Figure 8aA cross-sectional view schematically showing an example of a fluid controller is presented. When the magnetic fluxes (6), which are locally substantially vertically aligned, move from left to right, the constriction portion (10) moves along the active region (9), thereby transferring the fluid from the inlet to the outlet. The inactive region (3) of the device serves as the frame of the pump.

[0016] Figure 8b A pump made of a thin Ni-Mn-Ga sheet is shown. Before laser cutting the sheet into the shape of the pump as shown, a dense twin structure with equal proportions of twin variants 1 and 2 is made in the sheet. Then, the surface of the inactive region (3) is treated by laser to prevent the movement of twin boundaries. To maintain the dense twin structure, the active region (9) is slightly shot peened. The pump before constriction is shown in the figure, where the constriction is generated by rotating the radially magnetized permanent magnet (6) in the active region. In this pump design, the inactive region (3) of the device serves as the frame of the pump. The device is sealed with an elastomer, which is not shown in the figure.

[0017] Figure 9 A cross-sectional view schematically showing a fluid valve or an optical switch is presented. The active region is denoted by 9, and the inactive region is denoted by 3. The fluid or the beam of light flows through the hole (12) where the active region 9 moves. Detailed Description

[0018] The present invention includes a method for constructing twin variants and relates to an operating element made of a magnetic shape memory material, wherein a magnetic field is applied to at least one region of the device, thereby generating a deformation of the device in this region. At the same time, other regions of the device do not generate deformation in the applied magnetic field, but they have other functions in the device. The region where the magnetic field-induced deformation occurs is called the active region or the region responsive to the magnetic field of the device. The other regions (area or volume) of the device are processed or manufactured in such a way that their shape does not change due to the applied magnetic field. These regions are called the inactive regions or the regions non-responsive to the magnetic field of the device, but having other functions in the device. The inactive region can be used as the housing of the device, a spring, a gripper, a clamp, a manipulator, an injector, a mixer, a pump, a valve or a manifold or a part of their housing. The inactive region as well as the active region may also contain cavities, which can be fluid channels or chambers, or a part of the channels or chambers. The active region and the inactive region of the magnetic shape memory material source can also be used to guide the magnetic flux in the magnetic shape memory device. Special surface treatments can be used, such as deformation (shot peening, sandblasting or grinding methods), laser treatment or coating the surface with, for example, metals, ceramics, polymers, and other methods, to manufacture the inactive region. These regions can also be made inactive by mechanical clamping or squeezing. The present invention also relates to such a device, which is made by removing materials from polycrystalline or single-crystalline magnetic shape memory blocks, foils or films by using different methods such as chemical, electrochemical, electrical machining, lithography, laser engraving or cutting, ion beam milling or machining. The blocks, foils and films are also referred to as the source of the magnetic shape memory alloy hereinafter, or simply as the source of the alloy.

[0019] Any other manufacturing method of a structure that makes some regions of the device inactive and some other regions active can be used to manufacture the operating element of the magnetic shape memory device of the present invention. In the active region, the beneficial twin structure is usually dense. The dense twin structure can be stabilized by grinding, shot peening, sandblasting or deforming at least one surface of the active region by coating with an elastic coating.

[0020] Since devices made of magnetic shape memory materials with a single source can replace complex machinery composed of separate parts, the present invention will simplify many devices in various industrial applications. Compared with magnetostrictive and piezoelectric devices, the main advantage of the devices of the present invention is a deformation approximately 100 times greater, and after the magnetic field is turned off, the displacement generated by the magnetic field still remains. The present invention also relates to a device in which a single source of magnetic shape memory material containing at least one active region and at least one inactive region forms part of the device, and the device also includes other functional components made of materials other than magnetic shape memory materials or other functional components made of magnetic shape memory materials. For example, an embodiment of the present invention may include windings made of copper, or the device may be a valve composed of three parallel plates: the middle plate is made of magnetic shape memory material (operating element), and the other two plates are made of another material (including inlet and outlet holes) to seal the fluid passage. These embodiments are described in detail below.

[0021] Some features of the present invention are described below by selected examples. Figure 1 The gripper shown in [figure] illustrates how the inactive region functions in completing the mechanical movement of the device and why it is necessary to adjust the appropriate twin variant structure in the source of magnetic shape memory material before manufacturing the operating element. Before cutting the magnetic shape memory material plate into a gripper, the plate contracts axially (horizontally) into a single variant state, and the short crystal axis c is arranged axially. Then, the gripper is made from the plate. Certain regions (3) of the plate can be made inactive by laser treatment, and this region is shown in black. The active regions of the plate (1 and 2) are shown in gray. In Figure 1 the example shown in [figure]a, since the active region contracts axially before cutting the gripper from the magnetic shape memory plate, the gripper closes. Figure 1 Figure [figure]b shows the case where the gripper opens after a magnetic field with sufficient field strength is applied to the active region, which causes the elongation of the active region, where the long crystal axis a is along the axial (horizontal) direction and the short crystal axis is along the vertical direction. Due to the elastic force of the inactive region, the gripper can close by making the active region contract axially. The movement of the magnetic shape memory device of the present invention can be controlled by different methods. In small devices such as grippers, optical methods such as machine vision are useful methods and can be used to monitor the movement and shape change of the device. This optical information can be used to control the movement of the device.

[0022] In the device of the present invention, an external force, an applied magnetic field, or an elastic force can be used to effect the restoration of the active region (the elongation shrinks back to its original shape), which elastic force is formed by way of the inactive region, or a thin layer of an elastic coating, or a deformation of the surface of the active region, or by taking advantage of the magnetic shape anisotropy of the sample, i.e., in a thin foil, the magnetic field tends to align along the plane, while in a thin fiber, the magnetic field tends to align along the long dimension of the fiber. The magnetic field caused by the magnetic shape anisotropy tends to cause the fine fiber or foil to contract.

[0023] The active or inactive regions of a magnetic shape memory device can be used as a magnetic flux path. Figure 2 The general features of the present invention are schematically shown as to how the active and inactive regions are used to conduct the magnetic flux induced by an external magnetic field source (6). The twin variants are designated 1 and 2; the inactive regions (black) of the device are designated 3 and 5; the air gap is designated 4; and the magnetic flux lines are designated 7.

[0024] The alloy source or magnetic shape memory material source for fabricating the operating element, such as a plate, foil or film, can be in a single variant state or a multi-variant state. The multi-variant state can comprise a predetermined volume fraction of selected variants. Before fabricating the operating element from the source of magnetic shape memory material, a predetermined volume fraction of twin variants can be customized in the alloy source. Then, the movement of twin boundaries in the entire source of magnetic shape memory material can be blocked by at least one of the following ways of creating deformation, at least on the surface of the magnetic shape memory material source: abrasion, shot peening or sandblasting, laser treatment, or by covering the surface with a coating of sufficient stiffness. Then, the source of magnetic shape memory material is fabricated into the operating element using at least one of the following methods: machining, laser cutting or engraving, photolithography, etching, electromechanical machining, electroplating. After fabricating the operating element, the hindrance to the movement of twin boundaries in the active region is removed by using one of the following methods: electropolishing, etching, sputtering or grinding at least one surface (side) of the active region. A suitable twin structure, such as a dense twin structure, can be stabilized by at least one of the following methods: deforming the surface of the active region by abrasion or shot peening, or by laser treatment; or by coating the surface with an elastic coating, or by maintaining a partial pre-deformation of the entire source of magnetic shape memory material. Alternatively, the operating element can be made from a source of magnetic shape memory material in which the movement of twin boundaries is not blocked. In this case, the movement of twin boundaries is restricted only in the operating element by deforming at least one surface of the active region by abrasion, shot peening or sandblasting, laser treatment, or by applying a coating of sufficient hardness, or by mechanical constraint. The above methods can be used to stabilize a suitable twin structure in the active region.

[0025] The active region can be surrounded by an inactive region. In this case, the overall elongation and contraction of the active region are restricted. A local magnetic field applied to a partial active region can cause local strain in the active region, but the overall volume fraction in the twin variants remains unchanged. Along the axis of the magnetic shape memory element and orthogonal to the constrained end, hereinafter referred to as the axial direction, as Figure 3 shown. Figure 3 Figure 1 shows a top view of a twin-constrained magnetic shape memory element containing two twin variants with a predetermined volume fraction. Figure 3 Figure 2 illustrates three different configurations in which the volume fractions of twin variants 1 and 2 are the same. The volume fraction of variant 1 is approximately 30%. Figure 3 Figure 2a shows variant 1 in two separate parts. Figure 3 Figure 2b shows variant 1 in one part, Figure 3 Figure 2c shows variant 1 in several narrow parts. Let us assume, for example, that the magnetic shape memory element is made of a 10M martensite of a Ni-Mn-Ga alloy. When a part of the active region is affected by a local magnetic field of sufficient strength in a direction that is substantially parallel or substantially perpendicular to the horizontal (axial direction) in the active plane, that part of the element shortens in the direction of the magnetic field and stretches in the direction perpendicular to the magnetic field. Let us assume an element containing variants 1 and 2 with volume fractions of 30% and 70% respectively, as Figure 4 shown in Figure 3a. In this figure, the active plane is perpendicular to the surface in the figure and is aligned axially along it. Let us further assume that the short crystallographic axis c of variant 1 is aligned in the active plane and perpendicular to the axial direction, while the c-axis of variant 2 is in the active plane and aligned in the axial direction. When a local magnetic field of sufficient high strength that is aligned in the active plane and perpendicular to the axial direction is applied to a part of the element that was originally variant 2, the magnetic field causes the c-axis to rotate in the perpendicular axial direction, and thus, a new part of variant 1 is created. If the magnetic field influence covers at least 30% of the total volume of the element, the volume fraction of the new part of variant 1 is 30%, Figure 4 and the original variant 1 shown in Figure 3a becomes variant 2 because the total volume fraction of variant 1 is 30%. The resulting structure is as Figure 4As shown in b. This example illustrates a fundamental feature of the present invention, namely that when reconstructing parts of the variant by applying a local magnetic field at different positions of the element, the volume fraction of the variant is retained. These parts can be of any width and quantity. A wide part can be cut into thin parts, and vice versa. These parts can be moved sequentially in two directions along the element or discontinuously along the element. These parts can also consist of type I or type II twins, and the element can contain both types of twins simultaneously. When restricting the active area, the volume fraction of the twin variant remains constant before, during, and after changing the structure of the twin variant. Once the new twin variant structure is generated, it will remain unchanged even if the magnetic field is no longer applied to the element. Short magnetic field pulses can be used to generate the twin variant structure. This has great practical importance as it can prevent the electromagnet from overheating and save electrical energy.

[0026] Figure 4 The intermediate part (5) shown can be used for various applications. Other functional objects can also be attached to the intermediate part to improve its applicability. For example, the intermediate part can be used as a locking valve. The intermediate part can have a hole that can move relative to another fixed hole. When the holes are coaxially aligned, the flow rate can pass through the holes to the maximum extent. When the holes move relative to each other, the flow rate is restricted, and when the holes move apart from each other, the flow will stop completely. The intermediate part can also be used to close and disconnect a circuit. One switch can be installed in the intermediate part (5) of the device, while the second switch can be installed in the frame (3) of the device. The examples shown below illustrate these functions.

[0027] As shown by using Ni-Mn-Ga as an example material above, twin variants can be constructed by a local magnetic field having sufficient strength, which is in a direction within the active plane and substantially perpendicular to the axial direction of the magnetic shape memory element. For example, such a magnetic field can be generated by an electromagnet or a permanent magnet. At least two local magnetic field sources can be applied simultaneously to different positions of the element, thereby changing one variant into another at these positions. The local magnetic field source can be applied successively to the element, which thereafter means that the local magnetic field is applied continuously along its axial direction without increasing its width, so that a part of one twin variant travels along the element. The local magnetic field source can also be applied successively (continuously) and continuously (successively) to the element, which thereafter means that the local magnetic field is applied sequentially while maintaining its previous area, so that the width of the local magnetic field increases, and thus a part of one twin variant widens along the element. The magnetic field source can also be moved along the element, thereby changing the variant configuration at different positions of the element. The magnetic field source can be arranged on one side of the element, or can be composed of parts arranged on the opposite side of the element. At least one magnetic field source can be an electromagnet. If the electromagnets are placed side by side, they can form an array and can completely or partially cover the electromagnets. Using an array of electromagnets, the local magnetic field can be applied successively (continuously) or continuously (successively) to the element. Similar arrays can also be arranged on the opposite side of the element and can be connected to the electromagnets on the other side by a magnetic yoke. The electromagnets can also be arranged on one side and the magnetic yoke on the other side. Especially in thin and small structures, the windings can also be arranged on at least one side of the element without a magnetic yoke, or the magnetic yoke can be a ferromagnetic plate arranged on the side of the element opposite to the coil. In microelectromechanical structures (MEMS), flat coils can be manufactured using, for example, photolithography or laser cutting techniques. When the coil is magnetized with a short electrical pulse, the coil does not heat up significantly. Therefore, the current density in the coil can be very high, which allows for the use of smaller coils. On a small scale, the surface area to volume ratio is large, which also allows for a higher current density to be used in the coil. It is also possible to magnetize parts of the element axially. One such embodiment is a coil wound around the element. To achieve a sufficiently high magnetic field in the element, it is most advantageous to magnetize the coil using current pulses.

[0028] Figure 5 An example illustrating the present invention is shown. Figure 5 a shows a plate made of a magnetic shape memory material, which has two slits (4) cut, for example, using a laser or photolithography method. The plate is deformed, for example, by stretching ( Figure 5 b) or bending, such that the plate consists of two variants, the short crystallographic axes c of which are perpendicular to the plate surface (2) and parallel to the plate surface (1). Then, asFigure 5 As shown in c, the outer side of the plate is processed to make it in an inactive state (black region 3). The middle part of the plate is not processed, so it still responds to the magnetic field. The active region contains the volume fraction of twin variants, which is the same as the volume fraction presented by the plate originally.

[0029] A predetermined twin structure can also be made such that the c direction can be switched in a plane parallel to the plane of the figure. As Figure 6 shown, this operation can also be carried out after the side surface of the plate is processed to be inactive, for example, using surface treatment. Since the change in the element size caused by the magnetic field now occurs in the plane of the figure, the width of the slit will change. For example, it can be used for pumping in fluid applications. Parts can also be made to shrink or form other shapes in the slit region. These parts can move along the element and are used in many applications, such as in fluidics for transporting fluids. Figure 7 shows an example in which the center line (A - A) of the element moves to the right ( Figure 7 b), resulting in an increase in the volume fraction of the variant with the short c - axis located axially to the right of the mid - point and a decrease in the volume fraction of the variant on the left side of the mid - point. Figure 7 c shows the final situation, where the overall right side of the A - A line is one variant in which the c - axis is aligned axially, and the overall structure on the left side of the A - A line is one variant in which the c - axis is aligned in the vertical direction of the figure.

[0030] In the device according to the present invention, the twin boundaries between the twin variants in the active region can be of type I or type II. For example, the twin boundaries of type II twins move at a much lower magnetic field strength than those of type I twins in a 10M martensitic Ni-Mn-Ga alloy, and their movement has a smaller dependence on temperature. Therefore, we prefer to use type II twins in some devices manufactured according to the present invention. In 14M martensite, the type I and type II twin boundaries move at a very low magnetic field strength. 14M martensite is suitable for applications with higher operating temperatures because the austenite start temperature of 14M martensite can be higher than that of 10M martensite. It should be emphasized that the present invention is not limited to 10M or 14M martensite of Ni-Mn-Ga-based alloys, but can be all such materials that can exhibit the magnetic shape memory effect. The present invention simplifies complex devices in a variety of industrial applications by replacing complex mechanical equipment. Examples of application fields are optics, fluid technology, microengineering, robotics, manipulation, and biomedicine. By changing the local twin variant structure, the surface angle related to the element axis can be changed. This helps to change the reflection angle of an optical element and can be used in applications such as optical separation, optical switches, and interferometers. The continuous movement of at least one contraction position can be used to transport materials, such as fluids, along the magnetic shape memory element, thereby forming a pump or a linear motor. Additionally, the discontinuous movement of at least one contraction position can be used to quickly switch between multiple contraction structures, thereby allowing precise valve control and enabling the ability to create manifolds. The present invention is particularly important in micron- and nanoscale devices because the entire device containing multiple functional components can be made from a single source component made of magnetic shape memory material.

[0031] The present invention includes several uses of the method and device. In the following sections, some examples of the use and applicability of the present invention are provided. It should be emphasized that the present invention is not limited to those examples. The illustrated embodiments mainly illustrate some features of the present invention.

[0032] Example 1

[0033] The gripper is made of Ni-Mn-Ga foil with a thickness of 0.1 mm. The foil is compressed in a single deformation state, and then the surface of the foil is deformed by shot peening to prevent the movement of twin boundaries. It is cut from the sheet with a laser beam into a shape similar to the Figure 1 illustrated gripper. The length of the gripper is 5 mm and the width is 2.6 mm. After cutting, the non-active area is covered with a layer of paint, and the gripper is electropolished. The paint layer prevents the electropolishing of the non-active area. The active area is electropolished to retain the deformed part after shot peening and to stabilize the dense twin structure formed by the applied magnetic field. The operation of the gripper is demonstrated by applying a magnetic field to the active area.

[0034] Example 2

[0035] Figure 8a Shows the principle of a pump made of a Ni-Mn-Ga sheet. The active region (9) serves as a pumping element. The ratio of twin variants 1 and 2 is 70% and 30%. The external local magnetic field (6) produces a contraction in the active region. When the locally magnetic flux (6) aligned basically vertically moves from left to right, the contraction part (10) travels along the active region (9), thereby transferring the fluid from the inlet to the outlet. The inactive region (3) of the device serves as the frame of the pump.

[0036] Figure 8b Shows another embodiment of a pump made of a Ni-Mn-Ga sheet. Before laser cutting the sheet into the shape of the pump as shown, a dense twin structure with equal proportions of twin variants 1 and 2 is made in the sheet. Then, the surface of the inactive region (3) is blocked from twin boundary movement by laser treatment. To maintain the dense twin structure, the active region (9) is slightly peened. Figure 8b Shows the pump before the contraction is generated by rotating the radially magnetized permanent magnet (6) in the active region. In this pump design, the inactive region (3) of the device serves as the frame of the pump. The device is sealed with an elastomer, which is not shown Figure 8b in the figure.

[0037] Example 3

[0038] If an element is constrained between objects (such as plates or bars) that have a basically flat surface and another basically flat surface that is constrained at both ends, then when at least one local magnetic field source is applied to the element, the object can move axially with respect to the element. This is based on the fact that the dimensions of the element change locally. For example, in a 10M Ni-Mn-Ga alloy martensite, at the positions where it contracts in those perpendicular directions, the element elongates axially. When the contraction moves along the element, the plane located on the element moves along the element. This is the principle of a linear motor, the operation of which has been demonstrated.

[0039] Example 4

[0040] The device can be a microfluidic device, for example, a lab-on-a-chip. Cavities for microfluidic channels and chambers can be fabricated in the device, for example, in its inactive part. Pumps, valves, manifolds, mixers, and other devices can be made in the active parts of the same source piece of magnetic shape memory material. One embodiment of a lab-on-a-chip according to the present invention consists of a magnetic shape memory plate placed between two polymer plates, which can also contain fluid channels and chambers.

[0041] Example 5

[0042] Figure 9An embodiment of a device is shown, which can be used as, for example, a fluid valve or an optical switch. Depending on the applied magnetic field strength, the holes (12) move all or part of the way from one end (position 1) towards the other end (position 2). Thus, the opening for the path of fluid flow or light beam can be complete or partial. The active region is denoted by 9 and the inactive region by 3. The device is made from a Ni-Mn-Ga sheet by laser machining. Before cutting the device out of the Ni-Mn-Ga thin sheet, a narrow twin structure with a 50-50 twin variant ratio is formed by bending the thin sheet. The device is cut out of the thin sheet using a laser beam. In the inactive region, i.e., the frame (3) and the component (5) of the device, the movement of twin boundaries can be blocked by laser treatment of the surface. Figure 9 a) Shows the magnetic flux distribution in the active region of the device and in the inactive region (the frame of the device) when the right active region is magnetized with a magnetic field pulse guided to the coil. Figure 9 b) Shows a similar situation when the left active region is magnetized. This example shows that the inactive region of the device also conducts the magnetic flux in the device of the present invention. The computer modeling of the device corresponds well to the experimental measurement data of the device. The switching between positions 1 and 2 occurs within a few microseconds.

[0043] Example 6

[0044] The device can be an electrical switch or a circuit breaker. An embodiment of such a switch is made from a Ni-Mn-Ga alloy thin sheet by laser machining. The construction and working principle of the device are similar to Figure 4 the device shown. The difference from Figure 4 the device shown is that the back-and-forth movement of the component (5) is used to open and close the electrical contacts. The electrical contacts are electrically insulated from the device. The measured switching time is a few microseconds. The electrical switch and circuit breaker according to the present invention have great commercial potential, especially in microelectronics for switching high-frequency currents.

[0045] Example 7

[0046] The device according to the present invention can include at least one active region, the shape of which is changed by bending or kinking in the applied magnetic field. The bending can be achieved by applying a non-uniform magnetic field with a sufficient field strength to the active region. If one surface of the active region is made inactive while the other side remains active, bending will also occur in a substantially uniform magnetic field. The active side generates strain through the magnetic field while the inactive side does not generate strain, which results in the bending deformation of the active region. The device can also contain several active regions that bend in the applied magnetic field. This type of device can be used for, for example, mixing fluids.

[0047] It should be emphasized that all the examples shown above are only used to illustrate certain features of the present invention. The present invention is not limited to these embodiments.

Claims

1. A method of manufacturing an operating element, which is used alone or as part of a device, the operating element comprising a magnetic shape memory alloy having a twin variant structure as a source member, the twin variant structure having twin boundaries between the variants, characterized in that, a) Before manufacturing the operating element from the source member and before creating active and inactive regions in the source member, a predetermined twin variant structure is created to form the source member having magnetic shape memory, so as to create the active region, or a part of the active region generates a magnetic field-induced deformation required to perform its function in the operating element. b) At least a part of the source member for manufacturing the operating element is set as an active region, and the active region responds to a magnetic field, which is used to perform a function that requires deformation in the operating element, and c) At least one other part of the same source member is set as the inactive region, wherein when a magnetic field is applied to the inactive region in the operating element, the twin boundaries between the twin variants do not move.

2. The method for manufacturing an operating element according to claim 1, characterized in that, The active and / or inactive regions are formed to perform at least one of the following functions: serving as a frame of the operating element; conducting magnetic flux; Generating elastic force to facilitate the restoration of the deformation of the active region; switching current; serving as a clamp; serving as an optical shutter; serving as a valve; serving as a manifold; serving as a part of a microfluidic chip including fluid channels or chambers.

3. The method for manufacturing an operating element according to claim 1, characterized in that, The source member of the magnetic shape memory material including at least one active region and at least one inactive region is part of a device, and the device further includes other functional components made of materials other than the magnetic shape memory material, or other functional components made of the magnetic shape memory material.

4. The method for manufacturing an operating element according to claim 1, characterized in that, Compress or stretch the source member into a single variant state using a magnetic field or mechanical force.

5. The method for manufacturing an operating element according to claim 1, characterized in that, Create two twin variants with a predetermined volume fraction in the source member.

6. The method for manufacturing an operating element according to claim 5, characterized in that, In the source member, create two twin variants one and two, and the volume fraction of variant one is at least 10%.

7. The method for manufacturing an operating element according to claim 6, characterized in that, In the source member, adapt the volume fractions of the two twin variants to 50 - 50%.

8. The method for manufacturing an operating element according to claim 5, characterized in that, In the source member, the twin variants are evenly distributed.

9. The method for manufacturing an operating element according to claim 5, characterized in that, In the source member, the twin variant structure is made dense and contains thin twins.

10. The method for manufacturing an operating element according to claim 5, characterized in that, In the source member, the twin variant structure is stabilized by surface treatment.

11. The method for manufacturing an operating element according to claim 10, characterized in that, In the source member, the twin variant structure is stabilized by one of the following methods: deforming the surface of the active region by abrasion or shot peening; by laser treatment; by coating an elastic coating on the surface.

12. The method for manufacturing an operating element according to any one of claims 1-11, characterized in that, Prevent the movement of twin boundaries throughout the source member by surface treatment.

13. The method for manufacturing an operating element according to claim 12, characterized in that, Prevent the movement of twin boundaries throughout the source member by deforming one surface of the source member by abrasion, shot peening or sandblasting, laser treatment, or coating with a sufficiently hard coating.

14. The method for manufacturing an operating element according to claim 12, characterized in that, The operating element is manufactured from the source member using one of the following methods: machining, electro-mechanical machining, electrolysis.

15. The method for manufacturing an operating element according to claim 14, characterized in that, The machining is laser cutting or engraving, and the electro-mechanical machining is photolithography or etching.

16. The method for manufacturing an operating element according to claim 14, characterized in that, The movement obstruction of the twin boundary in the active region is removed by using one of the following methods: electropolishing, etching, sputtering or grinding on at least one surface of the active region.

17. The method for manufacturing an operating element according to claim 16, characterized in that, The twin variant structure is stabilized by surface treatment.

18. The method for manufacturing an operating element according to claim 17, characterized in that, The twin variant structure is stabilized by one of the following methods: deforming the surface of the active region by abrasion or shot peening; or by laser treatment; or by coating the surface with an elastic coating; or by maintaining the previous deformation of a part of the entire source member.

19. The method for manufacturing an operating element according to any one of claims 1 to 11, characterized in that, The operating element is manufactured from the source member, wherein any method can be used to remove the movement obstruction of the twin boundary.

20. The method for manufacturing an operating element according to claim 19, characterized in that, The movement of twin boundaries in the inactive region is blocked by surface treatment.

21. The method for manufacturing an operating element according to claim 20, characterized in that, The movement of twin boundaries in the inactive region is blocked by deforming at least one surface of the inactive region by abrasion, shot peening or sandblasting, laser treatment, or by coating with a sufficiently hard coating, or by mechanical constraint.

22. An operating element for use alone or as part of a device, the operating element comprising a magnetic shape memory alloy having a twin variant structure as a source member, the twin variant structure having boundaries between the variants, characterized in that a) at least a part of the operating element is an active region responsive to a magnetic field, which is used to perform a function requiring deformation in the operating element, b) at least one other part of the operating element is an inactive region non-responsive to a magnetic field, which is used to perform other functions in the operating element, and c) the operating element has a predetermined twin variant structure, wherein the mobility of the twin boundaries between the variants has been set such that in the active region, the twin boundaries move to produce the required deformation of the active region, and in the inactive region, when a magnetic field acts on the inactive region of the operating element, the twin boundaries do not move.

23. The operating element according to claim 22, characterized in that, The active and / or inactive regions have a form for performing at least one of the following functions: serving as a frame of the operating element; conducting magnetic flux; generating elastic force, advantageously for restoring the deformation of the active region; switching current; serving as a clamp; serving as a light shutter; serving as a valve; serving as a manifold; serving as a part of a microfluidic chip containing fluid channels or chambers.

24. The operating element according to claim 22 or 23, characterized in that, The operating element of the magnetic shape memory material comprising at least one active region and at least one inactive region is part of a device, the device further comprising other functional components made of other materials or other functional components made of magnetic shape memory material.

25. The operating element according to claim 22 or 23, characterized in that, The source member has been compressed or stretched into a single variant state.

26. The operating element according to claim 22 or 23, characterized in that, The source member includes two twin variants.

27. The operating element according to claim 26, characterized in that, The source member includes two twin variants, and the volume fraction of the other variant is at least 10%.

28. The operating element according to claim 27, characterized in that, In the source member, the volume fractions of the two twin variants are 50-50%.

29. The operating element according to claim 22 or 23, characterized in that, In the source member, the twin variants are uniformly distributed.

30. The operating element according to claim 22 or 23, characterized in that, In the source member, the twin variant structure has a dense structure containing thin twins.

31. The operating element according to claim 22 or 23, characterized in that, The twin variant structure in at least one of the active regions has been stabilized.

32. The operating element according to claim 22 or 23, characterized in that, The movement of the twin boundaries throughout the source member is prevented by surface treatment.

33. The operating element according to claim 32, characterized in that, The movement of the twin boundaries throughout the source member is prevented by deforming at least one surface of the source member.

34. The operating element according to claim 22 or 23, characterized in that, The operating element is made from the source member by one of the following methods: machining, electromechanical machining, electrolysis.

35. The operating element according to claim 34, characterized in that, The machining is laser cutting or engraving, and the electromechanical machining is photolithography or etching.

36. The operating element according to claim 22 or 23, characterized in that, The local magnetic field applied to the active area of the operating element is generated using at least one electromagnet.

37. The operating element according to claim 36, characterized in that, The electromagnet is a set of electromagnets placed side by side, covering the element entirely or partially.

38. The operating element according to claim 36, characterized in that, At least one of the electromagnets is a permanent magnet.

39. The operating element according to claim 22 or 23, characterized in that, The magnetic shape memory material is a Heusler alloy.

40. The operating element according to claim 39, characterized in that, The magnetic shape memory material is a 10M or 14M martensite containing only the elements Ni, Mn, and Ga, or also containing other elements.

41. The operating element according to claim 39, characterized in that, The twin boundaries in the operating element are of type I or type II.

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