JPS60131940A - Alloy having thermally recovering function - Google Patents

Abstract

PURPOSE:To obtain a shape memory alloy showing its shape memory effect in a wide temp. range and usable at high temp. by adding a specified amount of Si to a shape memory Ti-Ni alloy. CONSTITUTION:High purity sponge Ti is mixed with electrolytic Ni so that 49.5atom% Ti and 50.5atom% Ni are contained, and the mixture is melted by high frequency vacuum induction melting in a graphite crucible to prepare a Ti-Ni alloy. High purity metallic Si is added to the Ti-Ni alloy by 5atom%, and they are melted with Ar arc to manufacture a Ti-Ni-Si alloy having a composition represented by formula 1 (where x=49-52 and y=0.5-10). A shape memory alloy having a considerably increased martensitic transformation start temp. (Ms point) and a considerably increased reverse transformation start temp. (As point) is obtd. The temps. are related to the shape memory performance. The shape memory alloy can be utilized as the material of a temp. sensor or a safety valve.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a +Ti-Ni type shape memory alloy.

Ti-Ni alloy has a remarkable shape memory effect (5hape-Mem) accompanying the reverse transformation of thermoelastic martensitic transformation.
ory-Effect below SME below 8 naE. ) (``Metal J February 13, 1966 issue, P, P 44-48).
It is also noticeable for the TiN1X alloy that the element is added (
It is known that SMEs exhibit similar characteristics.

Ti-Ni-Fe alloy is disclosed in Japanese Patent Application Laid-Open No. 47-2102,
Ti-Ni-Cu alloy is disclosed in Japanese Patent Application Laid-Open No. 53-28518.
, Ti-Ni-V and Ti-Ni-Zr alloys are shown in JP-A-53-149732. Also Ti-
3d transition element (V.

The results of a research report on the addition of Cr, Mn', Zr) are described in Tohoku University Senken Awa 28 (1972) 209-219.

However, alloys to which these elements are added tend to lower the martensitic transformation start temperature (hereinafter abbreviated as Ms point), which is related to shape memory functionality. Therefore, TiN1-Fe shown in JP-A-47-2102
The alloy is intended for use in pipe fittings that do not exhibit stress relaxation even at extremely low temperatures.

An object of the present invention is to develop a shape memory alloy for use as a temperature sensor and a safety valve.

By the way, the upper limit of the Ma humidity temperature of the TfNi alloy and the conventional 'l'1NiX alloy is about 75°C, and cannot be used for sensors and breaker that operate at temperatures exceeding 100°C.

The present invention is based on the knowledge that the operating temperature can be applied over a wide range in this manner. The present invention provides a highly hard shape memory alloy obtained by adding Sl to a T'iNi alloy. The TiN1si alloy according to the present invention is different from the conventional TiN1X (
X = Fe r Cu -) and Isuji, same composition T1N
This is different from the conventional method in which the Ms point tends to increase as the amount of Si added to the i alloy increases. That is, the present invention has the composition formula % formula % (where x=49 to 52, y=o-5 to '10)
It is an alloy with a heat recovery function expressed by:

Here, when X is outside the range of 49 to 52, no shape memory effect is observed. Further, if y is less than 0.5, there is no effect of increasing the transformation point (for example, Ms point), and there is no effect of increasing hardness. When y exceeds 10.

The Ms point decreases and the hardness becomes so low that hot working and cold working become difficult. Therefore, let y be sails 5-10.

The following will be explained based on examples.

Example-1 Sponde Ti (purity 99.9), electrolytic Ni (purity 9)
The weight of 9.9%) was adjusted to a ratio of Ti (49.5 atomic percent) and Ni (50.5 atomic percent) by high-frequency vacuum induction melting using a graphite crucible. 'T150''50 was obtained.A part of it was then cut with a ceramic cutter, metallic silicon (purity 99.9%) was added at a composition ratio of 5 atomic percent, and Ti was melted by argon arc melting.
A N1Si alloy was obtained. The analysis values at that time were: Ti: 47 atoms centr Nt: 48 atoms cent + S
i: 5 atoms/g-cents. After that, the resulting foam was processed into a test piece with a thickness of 0.5 mm by hot working and cold working, and was used as a sample for measuring mechanical properties at a transformation temperature of 2.

High-frequency vacuum induction melting is a method to obtain the same alloy in large quantities.') Tt: 47 atoms/9 cents, Ni
:48i child? It is possible to dissolve raw materials at a ratio of St: 5 atoms i4-cents at a time.

Example-2 The alloy shown in Table 1 was obtained by the method of Example-1, and M
The measurement results of the s point and the As point (reverse transformation start temperature) are shown in the table below.
Shown in 2. As shown in Table 2, there is a tendency for the Ms point + As point to increase as the St amount increases.

Example-3 To investigate the influence of Si added as a third element, Ti: 50.5 atoms i? based on the method of Example-1.
- Sen), Ni: 49.5 atoms 1? - T1Ni alloy consisting of Ti 49.5 atomic percent + Ni': 50.5 atomic percent
i alloys each sail 5 to 15 atoms of E-cent 8
Several types of TjNiSi alloys containing 1 were prepared.

FIG. 1 shows the influence of added Si on the Ms point.

As shown in Figure 1, as the amount of Si added increases, Ms
It was found that the points showed an increasing trend and reached a maximum value between 5 and 10 atomic percent.

The hardness of the obtained alloy is 195 to 7 on the Hiracas hardness.
50, but alloys up to the addition of +5 tslO atomic percent could be hot worked and cold worked, and no tendency for embrittlement was observed due to the addition, whereas si:is atoms and -
It was almost impossible to process the cent-added alloy by cutting. Even if it were possible, there were problems such as using expensive processing equipment and extremely poor processing efficiency, so it was limited.

Table 1 B 92 103 D 40 50 E 90 102 The Si alloy, which was processed again over the next few days, was able to recover at least 5 degrees against deformation below the Ms point.

FIG. 2 shows the influence of the amount of Si added on the hardness based on the examples, and it is observed that the hardness increases as the amount of Si added increases.

[Brief explanation of the drawing]

Figure 1 shows the effect of S+ addition to the T1Ni alloy below the Ms point. (a) shown here is Ti: 50.5
This is a diagram when 81 is added to a T1Ni alloy with atoms A'-cents, Ni: 49.5 atoms/e-cents, and (
b) is Tj: 49.5 atoms cent*Ni
: It is a figure when Sl is added to 1 set/t of 50.5 atoms. Figure 2 shows the effect of St addition on T1Ni alloy on hardness.
Figure 2 Ichiya 55 (Hara Ubarant)

Claims (1)

[Claims] 1. Composition formula %formula% ) An alloy with a heat recovery function represented by