JPS59219443A - Multi-changing type shape memory alloy and its production - Google Patents

Abstract

PURPOSE:To develop a shape memory alloy member having the different temps. at which the alloy restores the original shape after changing its shape and permitting shape restoration in plural stages with the change of temp. by incorporating specific elements in the plural parts of the shape memory alloy. CONSTITUTION:Elements such as Al, Si, etc. forming a solid soln. with Ni or Ti are stuck partially nonuniformly on a wire rod, etc. of a shape memory alloy consisting essentially of Ni and Ti and the alloy is uniformly heated to penetrate the Al, Si, etc. therein at different amts. thereby forming a solid soln. A martensite transformation point M is different in the part where the Al, and Si are penetrated and solutionized at the partially different amt. from the Ni-Ti alloy. If such shape memory alloy is heated successively after the alloy is deformed, the alloy restores the original shape at different temps. and the multi- changing type shape memory alloy restoring successively the original shape at different temps. is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-deformable shape memory alloy and a method for manufacturing the same, and particularly relates to a multi-deformable shape memory alloy and a method for manufacturing the same, particularly when the shape-recovery form changes into a plurality of forms, in other words, when the shape-memory alloy recovers to its original shape due to a temperature change. The present invention relates to a shape memory alloy that changes shape stepwise or continuously, rather than recovering its shape, and a method for manufacturing the same.

In recent years, shape memory alloys, which have been attracting attention as unique functional materials, are generally thermoelastic type martensitic alloys that do not undergo transformation, and when heated to a critical temperature, A material that begins or attempts to recover from its shape at temperature to the original shape of the alloy. The characteristic of such alloy tooth material is that it undergoes a phase change that starts at a critical temperature, that is, a temperature called the transformation (thermoelastic martensitic I-transformation) temperature. Conventionally N +-1
″i.

Shape description 1.1 Alloy elements such as N1--ΔA, C, u-Zri system, Cu-Δβ-Ni, etc. are known.

However, all of these conventional shape memory alloys are deformed in the direction of thermal force, for example, in the direction of temperature increase or in the direction of temperature decrease, for example, from a straight state to a curved state,
Or, since it deforms in the opposite direction, use such a moon)'-1.

When the shape memory alloy is configured to have a shape memory alloy of 1,000,000, etc., the shape memory alloy is deformed by heat, and only one change from ON to OFF or OFF to ON is caused. In this case, if there is a Toha-responsive actuator made of a 1q alloy whose shape is deformed by -C2 deformation or more in the direction of thermal force, then ON-OF F→ON,
A switch that changes multiple times, such as OF F -ON-→ON, etc.
7 switches can be constructed and very useful switch operations can be performed.

Even in ON/OFF valves, the springs that actuate the valve body take on multiple or continuous deformations in the thermal direction (4). If it can be used, it has the advantage that it can be used as a valve that adjusts the flow rate rather than just turning ON and OI''F depending on changes in ambient temperature.

The present invention has been made against the background of such circumstances, and its purpose is to provide a shape that changes in a variety of ways by taking a plurality of shape recovery modes when recovering to its original shape due to temperature changes. An object of the present invention is to provide a memory alloy and a manufacturing method thereof.

In order to achieve this object, in the present invention, in a shape memory alloy that undergoes thermoelastic martensitic transformation, portions with different transformation temperatures are provided within one shape, and the shape is changed by temperature change. When recovering, it is possible to take multiple forms of shape recovery.

Thus, in the shape memory alloy according to the present invention, the martensitic transformation 'l is integrally formed within one shape.
+! ! , where parts with different degrees are formed,
According to each different transformation temperature, each part exhibits a shape of 1,0 and induces reverse transformation), so -
・In the integral part H of the ri, a shape recovery form according to each of the above-mentioned reverse transformations appears in a part of the shape, and as a result, a plurality of shapes (summer forms) are taken.

Incidentally, FIG. 1 shows the multi-variable shape description 1. according to the present invention.
This figure shows a model of the shape of a coil spring made of one alloy. In FIG. 1, the left and right halves of the spring 2 (in the figure) have different martenzite transformation temperatures (Ms) (for example, the left side is low and the right side is high lvl s, T = j After the spring 2 is subjected to the treatment described in 1.a according to the method of Tsutomi, it is deformed (b), and this deformed material is heated. Then, in step (C) of heating above the low MS point, the left half of the spring 2 undergoes reverse transformation and recovers its original shape.Furthermore, In step (d) where heating is continued to exceed the high Ms point, the right half of the spring part is also deformed, recovering its original memorized shape, and the whole as a whole returns to its original memorized shape. It will return to its original shape.

In this way, the metamorphosis'IA within one shape! Once the two MS have different parts, upon recovery to the original memory shape according to the temperature change? The shape recovery form of Mfi will be induced.

Further, FIG. 2 shows an example in which the shape description unique alloy according to the present invention is applied to a switch.
is a switch element made of a geometrically unique alloy according to the present invention, which has been subjected to the usual memory treatment (a) and has been deformed (b);
Depending on the difference in the transformation temperature: MS of the shape,
(C) respectively.

As in the step (d), different shape recovery forms are taken, and each contact point 6 is connected to -U. In this way, since the switch element 4 can assume a plurality of shape recovery modes as the temperature increases, it can perform a plurality of operating modes in accordance with the temperature.

Here, the shape memory alloy used in the present invention is an alloy material that causes thermoelastic martensitic transformation, such as 'l'1-Ni, Ni-Al! ,Cu-
Zn, Cu-Zn-X (X=S i.

Sn, A6. In shape memory alloys with such alloy compositions, it is possible to list various known ones such as Ga) and Cu-Al2-Ni. One of the components, or in the case of a three-component system, one or two of the components),
The shape ratio is 1. In an object of a predetermined shape made of a alloy,
In other words, the shape memory alloy material (
As a result, parts with different martensitic transformation temperatures (MS) are formed within one shape.

Note that this martensitic transformation temperature: M s can be suitably changed in the longitudinal direction or width direction of the object made of the shape memory alloy, but it can also be changed in the thickness direction of the object. It doesn't make any difference even if it's something you have. In addition, such portions with different transformation temperatures within one shape may be formed from such a shape memory alloy as a portion where the transformation temperature changes stepwise or as a portion where the transformation temperature changes continuously. It will be formed into an object.

Shape memory alloys (objects) that have parts with different transformation temperatures within one shape can be formed by using alloy materials with different materials (alloy compositions) when forming them into a predetermined shape. The alloy material according to the present invention can also be suitably manufactured by the following method.

That is, one of them consists of an alloy composition that can express a predetermined shape ratio effect of 1.1, and a shape memory alloy phase 1 having a predetermined shape is carved, and some of the alloy components are This is a method of forming regions with different thermoelastic martensitic transformation temperatures by allowing elements that preferentially bond to materials to infiltrate unevenly locally. More specifically, when an i'i-Ni alloy is used as a shape memory alloy, nitrogen, carbon, etc. are elements that preferentially combine with the alloy component 1i. By carburizing or nitriding a weld metal with a shape ratio of 1 non-uniformly (by varying the treatment temperature).

The infiltrated element forms a compound with one component (T+) of the shape memory alloy components, thereby changing the alloy composition with the other component (Ni), As a result, portions having different martensitic transformation temperatures can be effectively formed within one shape.

In addition, as another advantageous molding method, for an alloy composition that can express a predetermined shape ratio unique effect, a part of the alloy component A method is adopted in which regions with different thermoelastic martensitic transformation temperatures are formed by locally containing at least one element that forms a solid solution with the material. More specifically, for example, one or more elements that form a solid solution with Ni or i'i, such as Al1.Si, etc., are non-uniformly added and contained in a shape memory alloy mainly composed of Ni and 'i'. This type of uneven addition and inclusion of certain elements is achieved by attaching such elements to the surface of the shape memory alloy material and heating it unevenly, in other words, adding and containing certain elements locally. This can be done by varying the heating temperature to change the amount of the element penetrating into the shape memory alloy material.The penetrating element is then added to the alloy component (Ni) in the alloy material. Also, by forming a solid solution with 'I''i), the alloy composition can be easily changed.Therefore, by varying the amount of this penetrating element, regions with different martensitic transformation temperatures can be easily formed. It can be done.

Note that the above two methods can be carried out after the shape memory alloy has been processed into a predetermined shape (for example, a wire moon, a bar shrine, a plate + A, etc.), and in this respect, there is no difference between the two methods. 〇It has excellent characteristics.

The multi-deformable shape memory alloy according to the present invention, which is manufactured by various methods such as
It develops multiple shape cycles (summer morphology) stepwise or continuously over a wide temperature range, and this significantly expands the applications of such shape memory alloys.
It's H. For example, specific applications include valves that control the flow rate depending on temperature, or valves that control air volume, which are conventionally ON or OFF? Actuation, in other words, it is applied to all applications of shape memory alloys used in one variation form. As a child, °C is advantageously used.

Examples of the present invention will be shown below to clarify the present invention more specifically, and it goes without saying that the present invention is not subject to any limitations by the description of these Examples. .

Example I 50 with a transformation point of MS=35°C (Af=50°C)
atomic %Ni50 atomic %i' i By passing the shape memory alloy alloy through a molten Aβ bath, A is deposited on its surface.
! :, +-ting.

Next, the Aβ-coated shape memory alloy material was placed in a furnace where one end was water-cooled and the other end was heated to 900°C, with a continuous temperature gradient between the two ends, and was heated for 5 hours. By performing the heat treatment, All was infiltrated into the material to obtain a shape memory alloy (1) in which the amount of penetration in the material changes continuously in the longitudinal direction.The atmosphere in this heat treatment furnace was The atmosphere was Ar (1 atm).

A tension-type coil spring was manufactured using the Δβ penetration shape ↑5a alloy obtained in this way, and 3 (1(1”C/I!)
! Amnestic treatment was performed at L degree for 3 hours.

A coil spring made of a shape memory alloy treated with °C memory treatment is hung vertically at room temperature, and a predetermined weight is placed at the end of the °C, and when the temperature is changed, The state of change in the coil wings was investigated, and the results are shown in Figure 3.

As is clear from the results in Figure 3, l of Δa in the longitudinal direction
d Coil wings made of shape memory alloy with different tails exhibit non-linear changes over a wide temperature range,
It was recognized that multiple forms of shape recovery could be induced.

Example 2 A material having a transformation point of 1, MS = 35°C (Δf = 50°C), 50 original J'%6Ni-5Q, similar to the shape memory alloy material used for the road side. atomic % Ti alloy under N2 atmosphere, 10 (10
℃): (The other end is water-cooled and heated to a low temperature of 1-℃, and the other end is heated to 1-℃.): (by heating for 5 hours, Non-uniform nitriding treatment was applied in the longitudinal direction.

A coil spring was made in the same manner as in Example 1 using the shape memory alloy material obtained in this manner, in which a portion in the longitudinal direction (one end portion) was nitrided, and the material was subjected to the 333 million treatment. When we evaluated the shape change, we found that the nitrided part recovers to its original shape at low temperatures, while the part that has not been nitrided shows a shape Dfi effect at higher temperatures. It was recognized that the whole body could take on multiple forms of shape recovery.

Example 3 Applying black 1) to a part of a shape memory alloy wire having a transformation point of M s = 35°C (Af = 50°C), 50 atomic % Ni - 50 atomic % i''i, This was carburized by adding lead to a temperature of 900° C. for 2 hours in air.

Thus, the part 53 obtained in step 7, which is partially carburized and infiltrated with C and is bonded to Ti and (y), is the original material part that has not been carburized It is recognized that the transformation point has decreased compared to that, and due to temperature change,
It has become clear that this material is a shape memory alloy material that exhibits multiple shape recovery forms.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing the form of shape change of the shape memory alloy material according to the present invention, and FIG. 3 shows i! 1. Shape description according to the present invention. It is a graph which shows the displacement amount with respect to heating temperature of alpha alloy charge. 2: Coil spring 4: Swissochi element applicant Daido Steel Co., Ltd.

Claims (5)

[Claims] (1) A shape memory alloy that undergoes thermoelastic martenzite transformation, which is a multi-deformable shape memory alloy that has parts with different transformation temperatures within one shape and induces multiple shape recovery forms. (2) The shape memory alloy according to claim 1, wherein the portions having different martensitic transformation temperatures are formed as portions where the transformation temperature changes stepwise. (3) The shape memory alloy according to claim 1, wherein the portions having different martensitic transformation temperatures are formed as portions where the transformation temperature changes continuously. (4) For a shape memory alloy material with an alloy composition that can express a predetermined shape memory effect, some of the alloy components may be
A method for manufacturing a multi-deformable shape memory alloy, which is characterized by forming regions having different thermoelastic martensitic transformation temperatures by unevenly infiltrating elements that combine in a cage-like manner locally. (5) In a shape memory alloy material having an alloy composition capable of exhibiting a predetermined shape memory effect, at least one element that forms a solid solution with some of the alloy components is locally and nonuniformly contained. A method for producing a multi-deformable shape memory alloy, characterized by forming regions with different thermoelastic martensitic transformation temperatures.