JPS5928548A - Superelastic shape-memory ni-ti base alloy and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase elasticity and shape-memory performance by the solution treatment and aging of the alloy composed of specified rate of Ni, Ti, V, Cr, Mn, Fe, Co, etc. at a specified temperature. CONSTITUTION:An alloy composed of 50-52atom% Ni and remainder Ti or an alloy of which not more than 1atom% Ni or Ti content is substituted with not less than one kind of V, Cr, Mn, Fe, Co, Cu, Zr, Nb, Mo, Ta and noble metals, is refined. After this alloy is solution-treated at a temperature of 700-1,100 deg.C, it is aged at a temperature of 300-600 deg.C. Thus, fine Ni3Ti phase is dispersed and precipitated in base phase and the alloy material excellent in superelasticity and shape-memory property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an N 1-Ti-based alloy material with excellent superelasticity and shape memory, and a method for producing the same.

The atomic ratio of Ni and Ti is 1=1 or near it.
Ni-Ti alloys containing cV, Cr,
Mn.

Fe, Co, CI, Zr, Nb, MO, 'l'
It is known that a unique phenomenon is exhibited by adding a, or a metal group.

This superelasticity is used as a high-performance spring material, and its shape memory is being put into practical use as a temperature sensor, actuator, or an element that also serves as a temperature sensor, actuator, etc. Therefore, C2 has sufficient performance, such as low residual strain and long life. However, long materials are required.

Ni-']' Metallurgical research has shown that it is effective to advance the 62 stress-induced martensitic transformation without causing dislocation slippage to the extent possible to improve the superelasticity and shape memory of i-based alloy materials. Target C2 can be predicted. Let us help you achieve this,
In addition to this, the temperature and Pr that do not cause recrystallization, e.g. 400
A method has been proposed in which shape memory treatment is performed at a temperature of 30 minutes. In the Ni-Ti base alloy material obtained by this method, the texture formed by cold working does not disappear by shape memory treatment, so it is difficult for dislocation slip to occur and external stress The stress-induced transformation progresses by 1" without being affected much. As a result, good superelasticity can be obtained above the transformation temperature, and good shape memory can be obtained beyond the transformation temperature.

However, since this method requires sufficient cold working (two times), it is effective when processing is easily carried out to the inside, such as thin wires and thin plates, but it is effective for thick wires and thick plates. Or, like bulk shapes, processing is not evenly supervised up to the internal parts.

Ni-containing scratches are 51. If the Oa exceeds 1%, it becomes hard and compositionally difficult to cold-work, there is a drawback that sufficient cold-working is impossible and therefore it cannot be carried out.

In view of this, as a result of various studies, the present invention has been developed by dispersing and precipitating a fine Ni3Ti phase in the parent phase of the alloy, which eliminates the need for cold working and achieves good overpass I/+- and shape. be.

That is, the Ni-Ti alloy material of the present invention has N of 150.0 to
52.0 at%, balance Ti, or 1.0 at% or less of the Ni or Ti content of the alloy, V, C
r, Mn, Fe, Co.

It is characterized by the fact that fine Ni and Ti phases are dispersed and precipitated in the matrix of an alloy which has been replaced with one or more elements selected from Cu, Zr, Nb, Mo, Ta, and the paleometal group. It is something.

Further, the method for manufacturing the Ni-Ti based alloy material of the present invention includes Ni50
．． 0-52. An alloy consisting of 1% Oa and the balance Ti, or an alloy with a Ni or Ti content of 1.0atSB or less.
, Cr, Mn.

An alloy substituted with one or more elements selected from the group consisting of Fe, Co, Cu, Zr, Nb, Mo, Ta, and metals is solution-treated at a temperature of 700 to 1100°C, and then heated to 300 to 600°C. It is characterized by aging treatment at a temperature of .

However, the reason why the composition range of one alloy is limited as described above in the N i -T i base rate of the present invention is as follows.

If it exceeds 52.081%, processing 1) will be significantly reduced, and cracks will occur even in hot manufacturing ≦2, so it is judged to have no practical value according to C2. Also alloy) containing Ni or Ti 31 (7) 1. ■ below Oat%,
Cr, Mn, Fe%Co-Cu%Zr, Nb, Mo
, Ta, and one or more of the metals in the metal group include ■, Cr, Mn, Fe, and G.

The substitution with Zr, Nb%MO%Ta has the effect of lowering the transformation temperature and controlling the transformation temperature on the low temperature side without significantly changing the superelasticity and shape memory properties of the alloy. The substitution with metal group 62 has the effect of improving the corrosion resistance without significantly impairing the superelasticity and shape memory properties of the alloy.

The total amount of substitution of these elements is l of the Ni or Ti content.
This is because if it exceeds at%, not only the workability is impaired but also the superelasticity and shape memory properties are deteriorated.

In addition, in the method 62 for producing the Ni-Ti based alloy material of the present invention,
The above Ni-Ti base alloy is solution-treated at a temperature of 700-1100°C and then aged at a high temperature of 300-600°C. ) [(94f !, let +41, superelastic and shape 1
Without deteriorating memory.

This is to prevent the occurrence of dislocation slips and to eliminate residual stoppage. Therefore, the solution treatment temperature is set to 7()0~
The reason why the temperature was limited to 1100°C is that if the treatment temperature is less than 700°C, solution treatment will not be carried out sufficiently, and if it exceeds 1100°C, some parts will melt or deformation will occur.

Solution treatment is carried out in an inert gas atmosphere, for example argon.
Heat to a temperature of 00 to 1100°C. Similar results can be obtained within this temperature range, and the opening when heated is 0.5 to 1O
Similar results are fqt within the time range.

The quenching is also at the same level as air quenching)! Although it is possible to obtain the characteristics of tl+, it is desirable to water-quench the material to ensure the appearance tl:.

In addition, the aging treatment temperature after solution treatment was limited to 300 to 600°C because aging precipitation is insufficient at temperatures below 300°C and good properties cannot be obtained.
:lI'l'(This is because good characteristics cannot be obtained because Ni3'l''i enters the single phase region.
Although it depends on the size of the treated material, the temperature of the shore is 1 at 400"C.
Similar results can be obtained within the range of ~10 hours, and good results can be obtained for practical C2 at temperatures of 350 to 450°C for 1 to 2 hours.

Hereinafter, the present invention will be explained in detail using two embodiments C.

An alloy having the composition shown in Table 1 was water-quenched by heating at a temperature of 1000°C, and then aged at a temperature of 500°C for 1 hour.
Regarding this, the martensite reverse transformation point (Af point), superelasticity, and shape memory were measured. The results are also listed in Table 1. For reference, the superelasticity and shape memory properties after solution treatment were measured, and the results are shown in Table 1.

Each alloy is melted in a vacuum high-frequency melting furnace C2 using a graphite crucible using a conventional method, and the ingot is cast into a water-cooled mold and subjected to hot forging and hot rolling, followed by repeated intermediate annealing and cold wire drawing. I finished it with a line with a diameter of 1.0 tuna.

However, since it was difficult to wire-draw the alloy A65 of the present invention, a sheet with a thickness of 1+m was finished by rolling.
A plate-shaped sample was cut into a length of 150 m. After removing the scale on the surface of these wire rods and plate materials, they were subjected to solution treatment at a temperature of 1000℃ for 1 hour in an argon atmosphere.
In ice water (second quenching, put it into a quartz tube and heat it at 500℃)
Aging treatment was performed at a temperature of 1 hour.

Shape memory properties are determined by winding a wire or plate material around an iron frame with a diameter of 11 IQms at a crystallinity of at least 20°C lower than the European temperature, removing it from the rod in that state, and heating it in warm water to achieve a deafening temperature of at least IW (20°C or more). The degree of recovery to a straight line shape when
In the above, those less than 175 degrees are marked with ○, and those less than 135 degrees are marked with Δ. Note that the transformation temperature was lower than room temperature F (for the two cases, winding was performed in a mixed solution of dry ice and alcohol).

In addition, superelasticity is measured by winding a wire or plate material at a temperature lower than the two-transformation temperature of an iron rod with a diameter of 10 mm, removing the winding force, and measuring the angle after recovery due to springback. This was shown in the same way as memorability.

As is clear from Table 1, the alloy material of the present invention is subjected to aging treatment after solution treatment.
It turns out that there is a second improvement. In addition, shape memory (repetitive characteristics) (2) If you pay attention, the shape memory is improved. For example, with a material that has been solution-treated, permanent deformation occurs after several hundred repeated deformations. However, with the aged alloy material of the present invention, it was actually possible to repeat ζ 200,000 times.

As can be seen from the comparison alloy 4J/l612.Δ613 (2), when the Ni content is less than 50.Oa, no improvement in properties is seen at all due to solution treatment and total effect treatment, and 52.0a Although we did not show any examples of the alloy material having a content of more than 1%, it was judged that it had no practical value because the workability deteriorated significantly and cracking occurred even after hot forging (2). l of Ni or Ti content
Comparative alloy materials 414 and l in which more than at% was replaced with pd
Comparative alloy material A15 in which 'e was substituted did not show any improvement in properties or special superelasticity even if it was subjected to aging treatment after solution treatment.

Note that Table 1 (2) shows examples of Pd and F2O as substitution elements for Ni or Tl content, but substitution of Zr, Nb, MOLTa, and the metal group shows the same effect as Pd;
Substitutions of Mn, 00, and Cu showed similar effects as Fe. Special ≦2 pd, Zr + Nb, Mo-'l'
Substitution with a and base group C= improves corrosion resistance without impairing superelasticity and shape memory properties, including -Fe, V-Cr,
Substitution with Mn, Co, and CuI has the effect of lowering the transformation temperature without impairing the properties of the alloy material, and is effective in controlling the transformation temperature to a lower temperature side.

As described above, according to the present invention, the Ni-'l'i-based alloy is subjected to C2 aging treatment after solution treatment, thereby eliminating the need for cold working (2. High performance superelasticity and J19 shape memory). The obtained product has a remarkable industrial effect.

Claims (1)

[Claims] fil N i 50.0-52. Oa 1%, balance T
1% or less of the Ni or Ti content of the alloy, Cr, Mn, Fe,
Co, Cu%7rr, Nb, Mo, Ta, and alloy matrix substituted with one or more elements selected from the blue metal group, tflj (two fine Ni5Ti phases were dispersed and precipitated) Superelasticity, shape memory Ni characterized by
-Ti-based alloy material. f21 An alloy consisting of Ni 50.0 to 52.0 a 1%, the balance being Ti, or the alloy containing Ni or Ti
1. Qat% or less ■, Cr, Mn, Fe, C
After solution treatment of an alloy substituted with one or more elements selected from O, Cu, Zrfib, Mo, Ta, and blue metal group at a temperature of 700 to 1100°C, 30
A method for producing a superelastic, shape-memory Ni-Ti-based alloy material, which comprises aging treatment at a temperature of 0 to 600°C. (31. The method for manufacturing a metal material claimed in the patent, which involves adding cooling water after solution treatment.