JP2005336534A - Shape memory alloy member, shape memorizing method therefor, and actuator for controlling flow rate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape memory alloy member which has satisfactory reliability and repeated reproducibility while having bidirectional property and is applicable to various uses, to provide a shape memorizing method therefor, and to provide an actuator for controlling a flow rate. <P>SOLUTION: The shape memory alloy member having bidirectional property has a low temperature memory shape on the low temperature side of a martensitic transformation finishing temperature or below and has a high temperature memory shape on the high temperature side of an austenitic transformation finishing temperature or above. Shape memorizing treatment for forming the high temperature memory shape is performed at the temperature side higher than the austenitic transformation finishing temperature, and shape memorizing treatment for forming the low temperature memory shape is performed by tensile strain working on the temperature side lower than the martensitic transformation starting temperature after the shape memorizing treatment for forming the high temperature memory shape. The shape memory alloy treatment method uses the shape memory alloy member. The actuator for flow rate control uses the shape memory alloy member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shape memory alloy member, in particular, a shape memory alloy member having a bidirectional property, a shape memory method thereof, and a flow control actuator including the shape memory alloy member.

  In general, the shape memory effect is irreversible unidirectional, and by giving a special treatment to the shape memory alloy, the alloy itself may be given bidirectionality. The use of the memory element alone as a bidirectional element is considered to contribute to the downsizing of the device, the simplification of the mechanism, and the like, and to the expansion of the field of use. However, the bi-directional memory characteristics of shape memory alloys have not yet reached a practically satisfactory level.

  Therefore, the alloy itself is unidirectional, and the present situation is that the bi-directionality is imparted as an element (bias method) by combining other parts such as a spring and a weight.

  For this reason, there is a problem in reliability that the configuration is complicated and the field of use is limited, or the reproducibility is low.

  In addition, research on bi-directional shape memory has been conducted on its manifestation method and mechanism, application to small actuators, etc., but it is said that sufficient characteristics have been obtained considering practical aspects. (For example, see non-patent documents (1) to (4)).

From the above, it can be said that a practical bi-directional shape memory alloy member having good reproducibility and applicable to various uses has not yet been found.
Takezawa Kazuyoshi, Sato Shinichi “Mechanism of Reversible Shape Memory”, Metals Journal, 1982, Vol. 21, No. 6, p. 403-407 Oshima, R .; Adachi, K .; “Reversible Shape Memory Effect of Cu—Zn Alloy (shape memory effect of Cu—Zn alloy)”, J Appl. Phys. (Journal of Applied Physics), 1975, Vol. 14, No. 4, p. 563-564 Kuribayashi Victory, Shimizu Seiji, Yoshitake Masaaki, Ogawakura, “Prototype and Transformation Characteristics of Reversible Shape Memory Alloy Thin Film Actuators”, Precision Engineering, 1997, Vol. 63, No. 4, p. 530-534 Soichi Waguri, Atsuko Uenaka, Naomasa Nakajima, Susumu Murakami, “Development of Micro Gripper for Microfactory Using Bidirectional Shape Memory Alloy”, Theory C, 2002, Vol. 68, No. 668, p. 1231-1238

  In view of the above, an object of the present invention is to solve the above-described conventional technical problems. That is, the present invention provides a shape memory alloy member, a shape memory method thereof, and an actuator for flow rate control, which are bi-directional, have good reliability and repeatability, and can be applied to various applications. With the goal.

  As a result of intensive studies to solve the above problems, the present inventors have found that the following problems can be solved by the present invention.

  That is, the present invention is a shape memory alloy member having a bidirectional property that becomes a low-temperature memory shape on the low temperature side below the martensitic transformation end temperature and becomes a high temperature memory shape on the high temperature side above the austenite transformation end temperature, Shape memory processing (high temperature memory shape processing) to be a memory shape is performed on the higher temperature side than the austenite transformation end temperature, and shape memory processing (low temperature memory shape processing) to be the low temperature memory shape is the high temperature memory shape. It is a shape memory alloy member characterized by being subjected to tensile strain processing at a temperature lower than the martensitic transformation start temperature after the shape memory treatment.

  By applying the shape memory treatment as described above, in particular, the tensile strain processing, strain is imparted in the shape memory alloy member, and in the temperature range from the martensite transformation end temperature to the austenite transformation end temperature, a high temperature memory shape is obtained. On the other hand, a reverse deformation behavior that is a reverse deformation shape is shown. Then, in the temperature range from the temperature at which the low temperature memory shape is obtained to the temperature exhibiting the reverse deformation behavior, the shape changes depending on the temperature, such as the low temperature memory shape or the reverse deformation shape.

  In general, shape memory alloys having unidirectional and bi-directional properties increase from the low temperature memory shape to the shape of the high temperature memory shape (towards the memory direction) as the temperature is raised from a low temperature state. Deformation occurs in the memory shape.

  However, the shape memory alloy member of the present invention is deformed in a direction opposite to the memory direction that occurs in the process of recovery to the high temperature memory shape in the reverse deformation temperature range until the high temperature memory shape is deformed. . In other words, as the temperature changes from low temperature to high temperature, the shape gradually changes into a low temperature memory shape, a reverse deformation shape, and a high temperature memory shape according to the temperature.

  In addition, by repeating the shape change between the low-temperature memory shape and the reverse deformation shape according to the temperature, it becomes possible to more effectively use each of the low-temperature memory shape, the reverse deformation shape, and the high-temperature memory shape, It can be set as the shape memory alloy member applicable to a wide use.

  The alloy composition of the shape memory alloy member of the present invention is preferably a Ti—Ni system. The tensile strain applied by tensile strain processing is preferably 5 to 13%.

  Further, the present invention has a low temperature memory shape on the low temperature side below the martensite transformation end temperature, and a high temperature memory shape on the high temperature side above the austenite transformation end temperature, and the temperature from the martensite transformation end temperature to the austenite transformation end temperature. A shape memory method of a shape memory alloy member having a bidirectional property showing a reverse deformation behavior that becomes a reverse deformation shape with respect to the high temperature memory shape in a range, after bending at a higher temperature side than the austenite transformation end temperature A shape memory method for a shape memory alloy member, wherein tensile strain processing is performed on a lower temperature side than the martensitic transformation start temperature or lower.

  By performing tensile strain processing on the low temperature side after bending on the high temperature side, strain is imparted in the shape memory alloy member, and the high temperature memory shape is in the temperature range from the martensite transformation end temperature to the austenite transformation end temperature. On the other hand, the shape memory alloy member can exhibit a reverse deformation behavior that exhibits a reverse deformation shape. As a result, a low-temperature memory shape, an inversely deformed shape, and a high-temperature memory shape can be obtained depending on the temperature. By using each shape, a shape memory alloy member that can be applied to a wide range of applications can be obtained. The tensile strain applied by tensile strain processing is preferably 5 to 13%.

  Furthermore, the present invention is formed of a shape memory alloy member having bidirectionality, and by rotating a flow rate control valve that closes the flow path by the pressure of the fluid, the flow path is opened to open the flow path. A flow control actuator for controlling a flow rate of a fluid flowing through a flow path, one end of which is fixed in the flow path and at a temperature higher than an austenite transformation end temperature, and a tip portion is separated from the flow control valve and the flow The shape that closes the passage is subjected to high temperature memory shape processing, and after the high temperature memory shape processing, the tip portion approaches or comes into contact with the flow control valve by tensile strain processing on the lower temperature side than the martensite transformation start temperature. An actuator for flow control, characterized in that low-temperature memory shape processing is applied to a shape for closing a flow path.

  Since the flow control actuator of the present invention uses the shape memory alloy member of the present invention described above, the low temperature memory shape, the reverse deformation shape, and the high temperature memory shape are selectively used according to the temperature, so that the fluid The flow rate can be selectively controlled.

  According to the present invention, there are provided a shape memory alloy member, a shape memory method thereof, and an actuator for flow rate control, which are bi-directional, have good reliability and repeatability, and can be applied to various applications. Can do.

[Shape Memory Alloy Member and Shape Memory Method]
The shape memory alloy member of the present invention exhibits reverse deformation behavior, and thus has a shape corresponding to temperature, that is, a low temperature memory shape, a reverse deformation shape, and a high temperature memory shape. Here, “reverse deformation” refers to a deformation that is directed in a direction different from the storage direction in which the high-temperature memory shape is obtained, specifically, in a direction in which the shape at the end of the reverse deformation is substantially in contrast to the high-temperature memory shape. . Such a shape memory alloy member of the present invention is produced by the following shape memory method.

  That is, first, a solution treatment is applied to the shape memory alloy material in the range of 700 to 1000 ° C. As the shape memory alloy material, an alloy material such as a Cu-Al based material or a Ti-Ni based material can be used, but a Ti-Ni based alloy may be used in consideration of strength, fatigue resistance, corrosion resistance, and the like. preferable. When using a Ti—Ni alloy, the Ni content in the alloy is preferably 49.5 to 51 at%, more preferably 50 to 50.5 at%. In addition, additives generally used for shape memory alloy materials may be appropriately contained. As the shape of the shape memory alloy material, various forms such as a wire and a plate can be applied.

  Next, the shape memory alloy material is subjected to, for example, bending as a processing for imparting a desired high-temperature memory shape. A high temperature memory shape process is performed at a temperature higher than the austenite transformation end temperature in a state where the bending process is performed and the shape is constrained (shape memory process). The heat treatment temperature in the shape memory treatment is preferably 250 to 600 ° C., although it depends on the components of the alloy. Moreover, it is preferable that the time hold | maintained at this temperature shall be 20 to 60 minutes. By setting the temperature range and time, a desired shape can be stored while maintaining a sufficient strength.

  After the shape memory treatment, the shape memory alloy material is subjected to tensile strain processing at a temperature lower than the martensitic transformation start temperature so that a low temperature memory shape is obtained (low temperature memory shape treatment). A known method can be applied to the tensile strain processing. The tensile strain applied by the tensile strain processing is preferably 5 to 13% (25 ° C.), and more preferably 9 to 11%. By making it 5 to 13%, practical reverse deformation can be obtained while maintaining the strength characteristics of the material.

  The reverse deformation is considered to be caused by the strain applied to the martensitic phase of the shape memory alloy member at low temperatures remaining as internal stress, which triggers the deformation. Therefore, it is considered that the possibility of reverse deformation is determined by the degree of residual stress present in the alloy. On the other hand, when the martensitic transformation start temperature is exceeded, there may be a slight amount of martensite phase, but practical reverse deformation is difficult to obtain. In particular, when the austenite transformation finish temperature is exceeded, the alloy becomes only an austenite phase and no reverse deformation occurs.

  From the above viewpoint, the temperature at which the strain applying process is performed is lower than the martensitic transformation start temperature. In order to develop reverse deformation more reliably, the entire structure of the alloy is preferably in a martensitic phase, and therefore it is preferable that the temperature be equal to or lower than the martensitic transformation end temperature of the shape memory alloy member. 5 to 40 ° C. is preferable. By setting the temperature to 5 to 40 ° C., the shape on the low temperature side can be efficiently stored.

  The shape memory alloy member of the present invention is produced by performing shape memory processing such as bending at a predetermined temperature as described above and subsequent tensile strain processing.

  In addition, the “shape memory alloy member” referred to in the present specification can take various forms such as a plate material and a wire material. These can be appropriately processed and used as various parts. For example, the shape memory alloy member of the present invention can be processed as known to be used as an easily attachable / detachable fastening part as shown in FIG. It can also be used as an actuator of the present invention as described later.

  Below, the fastening component shown in FIG. 1 is demonstrated. FIG. 1 is a diagram for explaining a use mode when the shape memory alloy member of the present invention is applied to a set pin as a fastening part.

  The stop pin 10 is provided with a slit in the tip direction of the shaft 10a. With respect to the set pin 10, on the high temperature side (above the temperature exceeding the austenite transformation end temperature), as shown in FIG. 1 (A), it curves so as to protrude outward from the base portion of the shaft 10a to the middle portion of the tip portion. Then, shape memory processing is performed while performing bending so that the curvature of curvature decreases from the middle part to the tip part. Then, as shown in FIG. 1B, tensile strain processing is applied to the set pin 10 so as to have a linear shape on the low temperature side (below the temperature lower than the martensite transformation start temperature).

  After performing a series of processes as described above, as shown in FIG. 1C, the stop pin 10 is inserted into the through hole of the fastening portion. Thereafter, heating is performed to the reverse deformation start temperature using a heat source such as a heater. Due to the heating, the retaining pin 10 exhibits a reverse deformation behavior that causes reverse deformation with respect to the high-temperature memory shape when the shape memory treatment is performed, and the slit portion of the shaft 10a is illustrated in FIG. The pin 10 is deformed so as to open to the outside and the fastening pin 10 fastens the fastening part well. It can be said that “transformation start temperature (As point), transformation end temperature (Af point)” and “reverse deformation start temperature, reverse deformation end temperature” are almost the same.

  In the case of releasing the fastening, heating is further performed at a temperature exceeding the reverse deformation temperature, and the high temperature memory shape is recovered as shown in FIG. By doing in this way, fastening can be canceled easily, without destroying fastening parts.

  If the set pin of this embodiment is used for fastening a recyclable part, it can be said that the recycle part can be easily disassembled, so that it is more effective.

[Actuator for flow control]
The flow control actuator of the present invention will be described with reference to FIG. First, the shape memory alloy member used for the actuator is linear or plate-like, and the L shape is used as the high-temperature memory shape, and the subsequent low-temperature memory shape is strained as a straight line by tensile strain processing. Keep it.

  As shown in FIG. 2A, a flow rate control valve 22 and a shape memory alloy member 20 as a flow rate control actuator are provided inside a pipe through which a fluid flows. Although the flow rate control valve 22 is provided so as to be rotatable around one end thereof, the movement toward the shape memory alloy member 20 is restricted by the protrusion 24 that functions as a stopper. The memory alloy member 20 is provided in a rotatable state on the side where the memory alloy member 20 is not provided. And at the low temperature which does not produce reverse deformation, the tip of the shape memory alloy member 20 is provided in contact with the flow control valve 22. This is because the fluid temperature is sensed via the flow control valve 22.

  Here, as the shape memory alloy member 20, the shape memory alloy member of the present invention described above can be used. The flow rate control plate is not particularly limited as long as it is a material that is not corroded by the fluid and can withstand the pressure received from the fluid, and is not particularly limited. A ceramic material such as a physical system can be applied. Furthermore, various liquids and gases can be applied as the fluid.

  In a range below the temperature at which the shape memory alloy member 20 exhibits reverse deformation behavior, the fluid flow path is closed by not rotating the flow control valve 22 as shown in FIG.

  When the temperature of the fluid rises and the temperature of the shape memory alloy member 20 enters the temperature range in which the reverse deformation behavior is exhibited, the reverse deformation occurs as shown in FIG. The shape memory alloy member 20 opens the fluid flow path while rotating the flow control valve 22.

  Thus, by using a deformation cycle in which the low-temperature memory shape and the inversely deformed shape are repeated according to the temperature, an actuator with good repeatability and high reliability can be obtained.

  On the other hand, when the temperature showing the reverse deformation behavior is exceeded, the shape memory alloy member 20 becomes a high temperature memory shape and is separated from the flow control plate 20, and the flow control valve 22 closes the fluid flow path. Thus, it can operate like a safety device against an abnormal temperature input equal to or higher than the reverse deformation temperature.

  The present invention will be specifically described by the following examples, but the present invention is not limited thereto. Note that “at%” indicates the atomic percentage of the metal in the alloy.

[Example 1]
(Production of shape memory alloy member (wire))
The nickel content is 50 at%, 50.75 at%, and 50.127 at%, respectively, and each shape memory alloy material of a Ti-Ni wire rod (made by Kanto Special Steel Co., Ltd.) having a diameter of 0.5 mm, A solution treatment was carried out at 900 ° C. for 30 minutes.

  Thereafter, a 180 ° U-bending shape was applied as the high-temperature memory shape, and a linear shape was applied as the low-temperature memory shape. In the case of imparting a high temperature side bent shape, the wire rod was placed in a stainless steel pipe and wound around a cylinder at room temperature to perform bending, and the shape memory treatment was performed in a constant temperature furnace while restraining the shape. The radius of the bending cylinder used at this time was R = 5, 10 and 15 mm (strains on the surface were 4.8%, 2.4% and 1.6%, respectively), and high temperature memory shape processing The temperature was T = 350 ° C., 400 ° C. and 500 ° C., and the holding time was 30 minutes.

  A shape memory alloy is obtained by applying a tensile test with a material tester at room temperature (25 ° C., the same shall apply hereinafter) to a shape memory alloy material storing a bent shape on the high temperature side at a low temperature side (low temperature memory shape). A member was prepared. The tensile strain was in the range of 3% to 17%.

(Evaluation)
With respect to these shape memory alloy members, shape changes with respect to environmental temperature changes of “room temperature → high temperature” and “room temperature → high temperature → room temperature → high temperature” were observed in the range of room temperature to 170 ° C. (high temperature). The environmental temperature change was performed with a silicon oil bath, and the shape change of the shape memory alloy member was recorded on a digital camera. Further, the transformation points of various shape memory alloy members were measured by a differential scanning calorimeter (DSC).

(result)
(1) Reverse deformation behavior:
FIG. 3 is a diagram showing a high temperature side shape recovery rate with respect to environmental temperature changes when bending deformation is stored on the high temperature side. The results are for the case of Ni content of 50.075 at%. The high temperature side memory treatment temperature is 400 ° C., the high temperature side memory shape is a 180 ° bent shape with a radius of curvature R = 10 mm, and the low temperature memory shape is a linear shape. is there. Unless otherwise specified, the following results relate to samples having a Ni content of 50.075 at%.

  The vertical axis in FIG. 3 is the shape recovery rate, which is the difference between the test piece angle at each temperature and the initial angle of the shape memory alloy member at room temperature as the recovery angle, divided by the high-temperature side processing angle of 180 °. It is.

  All the angles are declinations from the tangential direction of the sample. When the tensile strain is 5% or more, the recovery rate once takes a negative value and then rapidly changes to a positive value. The negative value of the recovery rate represents the occurrence of bending in the opposite direction to the added bending shape (reverse deformation behavior). In the present specification, as described above, such a deformation (reverse deformation behavior) in the direction opposite to the high temperature side memory shape accompanying the increase in the environmental temperature is referred to as reverse deformation.

  A general shape memory alloy monotonously recovers from a low temperature processed shape to a high temperature memory shape, but an example of an omnidirectional shape memory has been reported as an example of a specific shape change ( Satoshi Nishida and Toshio Honma: Tohoku University selection vocabulary report, 38-2 (1982) 75-84).

  However, in the case of the shape memory alloy member of this example, this is a phenomenon in which deformation occurs once in the reverse direction during the recovery by heating, which is different from the above example.

  An actual shape change process is shown in FIGS. In this example, the low-temperature-side tensile strain is 9%. From 80 ° C. in FIG. 4B to 88.6 ° C. in FIG. 4C, the bending memory in the right direction is reversed. A phenomenon of significant deformation was confirmed. After that, as shown in FIG. 4 (D), deformation occurred in the bending memory direction toward the right direction, and at 95 ° C., deformation occurred in a high-temperature memory shape as shown in FIG. 4 (E). . Such reverse deformation was reversed to a memorized shape all at once in a small temperature range.

(2) Maximum reverse deformation rate:
FIG. 5 shows the maximum value of reverse deformation with respect to the amount of tensile strain. At any shape memory processing temperature, the peak value was maximum when the low-temperature-side tensile strain was about 9%, and it was confirmed that the deformation was greatest when the memory processing temperature was 400 ° C.

(3) Reverse deformation behavior and transformation point:
In order to know the relationship between the reverse deformation behavior and the transformation point, differential scanning calorimetry (DSC) measurement was performed when bending was memorized on the high temperature side and tensile strain was applied on the low temperature side. “Transformation start temperature (As point), transformation end temperature (Af point) and peak temperature” obtained from DSC measurement were compared with “reverse deformation start, end and peak temperature”. As a result, it was found that the two were almost the same, and from this, it was found that the reverse deformation started with the transformation to the austenite phase and recovered to the high temperature memory shape with the end of the transformation.

  In the transformation to the parent phase, the transition to a crystal orientation different from that of the original parent phase leads to an increase in chemical free energy. Therefore, such transformation cannot occur, and non-chemical free energy is required for the initiation of transformation. Is required, and the difference in free energy between the martensite phase and the parent phase must exceed the non-chemical free energy value. Therefore, in this example, the deformation in the reverse direction after the start of transformation is caused by the strong processing from the 180 ° bending state to the linear shape resulting in an increase in non-chemical free energy, which is returned to the original matrix. It is considered that the internal stress field in the tensile direction introduced by strong processing acts as a driving force against deformation in the reverse direction, while it becomes a barrier to the transformation of.

  In addition, although deformation in the reverse direction once occurs, the free energy that the original matrix phase takes decreases with increasing temperature. Therefore, since the driving force to the original parent phase increases as the temperature rises, the free energy difference from the martensite phase increases, and the driving force to the original state becomes larger than the driving force in the reverse direction, It is thought that it will shift to the state of the original mother phase at once.

  This deformation in the reverse direction is expected to generate a large amount of reverse deformation as the driving force increases, so it is considered that the reverse deformation increases as the low-temperature side strain increases. This leads to a decrease in the internal stress field and the amount of reverse deformation is presumed to decrease.

(4) Effect of nickel concentration:
The above results relate to a material having a nickel concentration of 50.075 at%, and a similar experiment was performed on materials having different nickel concentrations in order to examine whether the reverse deformation is specific to this material.

  FIG. 6 shows the recovery rate for shape memory alloy members having different nickel concentrations, and is an example of low-temperature strain of 9%. In any composition, reverse deformation was exhibited, and the same tendency was observed in other tensile strains.

(5) Effect of temperature cycle:
7 and 8 show the results of observing the influence of the temperature cycle. In FIGS. 7 and 8, the temperature ranges are between room temperature and 170 ° C. and between room temperature and 90 ° C., respectively.

  As can be seen from FIG. 7, the sample once recovered to the normal memory shape did not undergo reverse deformation even when heated again after cooling (arrow (4) in the figure). However, as shown in FIG. 8, when cooled from the reverse deformation state and heated again, a shape change cycle occurs in the reverse deformation state.

  As described above, the reverse deformation is thought to be driven by internal stress, but once it has been heated to the limit value and recovered to a normal shape, the internal stress disappears, and then it can be reheated after cooling. It is assumed that reverse deformation does not occur. On the other hand, the internal stress remains if it is cooled from the heating up to the reverse deformation state, and repeated deformation occurs in the reverse deformation state if a temperature cycle is applied in this temperature range.

  FIG. 9 shows the change in the movable range of the angle in the reverse deformation state when a temperature cycle of 50 times in the range from 10 ° C. to 80 ° C. is given. The vertical axis indicates the movable angle as the initial angle. Dimensionalized. It can be said that reverse deformation can occur repeatedly even with respect to the temperature cycle.

[Example 2]
(Production of shape memory alloy member (plate material))
30 minutes at 900 ° C on a Ti-Ni plate (manufactured by Kanto Special Steel Co., Ltd.) with a nickel content of 50.2 at% and a width of 1.5 mm, a length of 100 mm, and a thickness of 0.8 mm A retention solution treatment was applied.

  As the memory shape, a 180 ° U-bending shape was imparted on the high temperature side, and a planar shape was imparted on the low temperature side. In the case of imparting a high temperature side bent shape, the plate material was put into a stainless steel pipe, wound around a cylinder at room temperature, bent, and subjected to a memory treatment in a constant temperature furnace while restraining the shape. The radius of the bending cylinder used at this time was R = 10 mm, the high temperature memory shape processing temperature was T = 400 ° C., and the holding time was 30 minutes.

  A shape memory alloy member was produced by applying a tensile stress to a shape memory alloy storing a bent shape on the high temperature side by applying a tensile stress to the shape on the low temperature side using a material testing machine at room temperature (25 ° C., hereinafter the same). The tensile strain was 9%.

(Evaluation and results)
The shape change with respect to the environmental temperature change of “room temperature → high temperature” was observed in the range of room temperature to 170 ° C. with respect to the produced shape memory alloy member.

  As a result, as shown in FIG. 10, a reverse deformation behavior having a peak at 92.6 ° C. was confirmed, and it was confirmed that a shape memory alloy member exhibiting the reverse deformation behavior even with a plate material could be produced.

As described above, the following items have been clarified by this example.
(1) It was confirmed that when the high temperature side memory shape was bent, and tensile strain was applied on the low temperature side, bending deformation in the direction opposite to the memory shape was developed in the shape recovery process by heating. The reverse deformation start and end temperatures corresponded to the austenite transformation start and end temperatures of the shape memory alloy member, respectively.

(2) Although reverse deformation does not occur even if a temperature cycle is applied in the temperature range that recovers to a normal shape (high-temperature memory shape), it can be confirmed that repeated reverse deformation occurs if a temperature cycle is applied in the reverse deformation expression temperature range. It was. Therefore, it was confirmed that the shape memory alloy member has good bidirectionality and reliability and repeatability, and can be applied to various applications.

(3) It was confirmed that a shape memory alloy member showing reverse deformation behavior can be produced even with a plate material.

It is explanatory drawing explaining the usage form of the stop pin as an application example of the shape memory alloy member of this invention. It is explanatory drawing explaining the usage form of the actuator of this invention. It is a figure which shows the high temperature side shape recovery rate with respect to environmental temperature change at the time of memorize | storing bending deformation in the high temperature side. It is a figure which shows the process of the shape change of the shape memory alloy member of an Example. It is a figure which shows the maximum value of reverse deformation with respect to the quantity of a tensile strain. It is a figure which shows the recovery rate with respect to the shape memory alloy member from which nickel concentration differs. It is a figure which shows the result of having observed the influence of a temperature cycle (room temperature-170 degreeC). It is a figure which shows the result of having observed the influence of a temperature cycle (room temperature-90 degreeC). It is a figure which shows the change of the movable range of the angle in a reverse deformation | transformation state at the time of giving a temperature cycle. It is a figure which shows the result of having observed the shape change with respect to the environmental temperature change of "room temperature-> high temperature" in the range from room temperature to 170 degreeC.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Stop pin 10a ... Shaft 20 ... Shape memory alloy member 22 ... Flow control board

Claims (6)

It is a shape memory alloy member having a bidirectional property that becomes a low temperature memory shape on the low temperature side below the martensite transformation end temperature, and a high temperature memory shape on the high temperature side above the austenite transformation end temperature,
The shape memory treatment to be the high temperature memory shape is applied on the higher temperature side than the austenite transformation end temperature,
A shape memory alloy member, wherein the shape memory processing to become the low temperature memory shape is performed by tensile strain processing at a temperature lower than the martensitic transformation start temperature after the shape memory processing to become the high temperature memory shape.   The shape memory alloy member according to claim 1, wherein the shape memory alloy member is a Ti-Ni alloy.   The shape memory alloy member according to claim 1, wherein a tensile strain applied by the tensile strain processing is 5 to 13%. The low temperature side below the martensite transformation end temperature has a low temperature memory shape, the high temperature side above the austenite transformation end temperature has a high temperature memory shape, and the high temperature memory has a temperature range from the martensite transformation end temperature to the austenite transformation end temperature. A shape memory method of a shape memory alloy member having a bidirectional property showing a reverse deformation behavior that becomes a reverse deformation shape with respect to the shape,
A shape memory method for a shape memory alloy member, wherein a shape memory treatment is performed on a higher temperature side than the austenite transformation end temperature, and then a tensile strain process is performed on a lower temperature side than the martensite transformation start temperature.   The shape memory method of the shape memory alloy member according to claim 4, wherein a tensile strain applied by the tensile strain processing is 5 to 13%. It is formed of a shape memory alloy member having bidirectionality, and the flow rate control valve that closes the flow path is rotated by the fluid pressure to open the flow path, so that the fluid flowing through the flow path A flow control actuator for controlling a flow rate,
One end is fixed in the flow path, and the high temperature memory shape processing is performed on the high temperature side from the end temperature of the austenite transformation, and the tip portion is separated from the flow rate control valve to close the flow path,
After the high-temperature memory shape processing, the low-temperature memory shape processing is applied to a shape that closes the flow path when the tip approaches or comes into contact with the flow control valve by tensile strain processing at a temperature lower than the martensite transformation start temperature. A flow control actuator characterized by the above.

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