JP2818995B2 - Clad wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clad wire having excellent elasticity, corrosion resistance and workability, and more particularly to a gold-clad shape memory alloy used as a decorative material for eyeglass frames, accessories, watch bands and the like.

[0002]

2. Description of the Related Art Shape memory alloys have functions such as a shape memory effect, superelasticity, pseudoelastic behavior and the like, and a wide range of research including development thereof has been promoted. Generally, shape memory alloys of Ni-Ti alloys have superior characteristics in terms of corrosion resistance, external force, ability to recover against heat, recovery rate, life, etc., as compared with shape memory alloys of Cu-Zn alloys. In particular, attention has been paid to its corrosion resistance and superelasticity, and its application to spectacle frames, which are ornaments, has been attempted (US Patent 4,772,112).
).

[0003] However, Ni-Ti alloys have poor workability,
In particular, it is inferior in cold workability, and it is difficult to remove surface flaws generated during working. For this reason, when the present invention is applied to an eyeglass frame requiring a beautiful appearance, there is a problem that the number of processing steps increases and the cost increases.

[0004] Furthermore, Ni-Ti alloys have poor plating and polishing properties, and have a problem that surface treatment cannot be performed well. Since Ni is contained, they are directly applied without coating treatment such as plating. When used on parts that come into contact with the skin,
There is a possibility that skin roughness due to Ni allergy may occur. Further, since it is difficult to directly braze Ni-Ti based shape memory alloys, there is a problem that they cannot be used for simple decorative articles.

[0005] As a countermeasure, the present inventor has proposed a clad wire rod capable of improving the workability of a Ni-Ti alloy without impairing the shape recovery performance and corrosion resistance (Japanese Patent Application Laid-Open No. Heisei 3─).
No. 82775). This clad wire is obtained by coating a Ni-Ti based shape memory alloy with Ti as an outer layer material, thereby improving workability and easily removing surface flaws generated during the work.

[0006]

According to this proposal, workability is greatly improved. However, parts of the eyeglass frame have a part with a very high degree of cold working, and Ni-Ti
There is a problem that the clad wire cannot be used in a portion requiring a high degree of cold working exceeding the bonding strength between the system shape memory alloy and the outer layer material for the following reason.

For example, when this wire is used for a bridge and a temple of an eyeglass frame in which the end face of the wire is exposed, after cold working, a core material of a Ni—Ti shape memory alloy and an outer layer material of Ti are used. May be broken and the appearance of the spectacle frame may be degraded. In addition, when an external force acts on the eyeglass frame by removing and attaching the eyeglasses in use, and the core material and the outer layer material are peeled off during the processing of the wire rod, the degree of this peeling is advanced, and the frame may be damaged. .

Further, if there is a defective bonding interface between the core material and the outer layer material in the brazing portion of the spectacle frame, a defect such as a void occurs when the frame is assembled. And peeling occurs from this void as a starting point while using glasses,
This peeling progresses, and the outer layer material portion of the rim to which the temple and the bridge are connected may break, and the frame may be damaged.

As described above, when the bonding condition between the core material and the outer layer material is poor due to the processing for manufacturing the product, not only the commercial value of the frame is reduced, but also the frame may be damaged while using the spectacles. There was a problem.

[0010] The present invention has been made in view of such circumstances, wherein the core material is a shape memory alloy, the outer layer material is made of gold or a gold alloy, and Ta, Nb or an alloy thereof is used as the intermediate material. To provide a clad wire that has a metallic luster on the surface, improves the strength of the joint interface and further enhances workability, and can be easily polished, plated, brazed, etc. Is a first layer made of gold or a gold alloy and Ni. Ni-based alloy, Cu, Cu-based alloy, or C
It is an object of the present invention to provide a clad wire rod that can be used in an amount that can be adjusted by being composed of a second layer made of an o-based alloy.

[0011]

According to a first aspect of the present invention, there is provided a clad wire comprising a core made of a shape memory alloy and an outer layer made of gold or a gold alloy covering the outer periphery of the core. Characterized in that Ta, Nb or an alloy thereof is interposed therebetween.

According to a second aspect of the present invention, in the clad wire, the outer layer material includes an outer first layer made of gold or a gold alloy, Ni, N
and an inner second layer made of an i-based alloy, Cu, a Cu-based alloy, or a Co-based alloy.

[0013]

In the clad wire of the present invention, Ta or Nb is applied to the outer periphery of the core of the shape memory alloy, and gold or a gold alloy is applied as the outer layer to the outer periphery. It is suitable for decorative articles with excellent workability. In addition, since Ta, Nb or their alloy is interposed between the core material and the outer layer material, the diffusion speed of metal atoms at the bonding interface between the core material and the outer layer material is reduced, and thereby, the bonding interface is reduced. By reducing the generated metal compound, the bonding strength at the bonding interface is improved.

In addition, the outer layer material is formed on the inner periphery of gold or gold alloy as the first layer, and Ni, Ni-based alloy, Cu, C as the second layer.
Since a corrosion-resistant metal such as a u-based alloy or a Co-based alloy is applied, the amount of gold or gold alloy used can be adjusted, for example, by reducing the amount of gold or gold alloy without reducing the thickness of the outer layer material.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a longitudinal sectional structural view of a clad material for a clad wire according to the present invention in a state where a core material, an intermediate material, an outer layer material, and a protective material are fitted. Fig. 2 (a)
FIG. 2 is a cross-sectional structural view taken along line II-II in FIG. In the clad material 1, a round bar core material 11 made of a Ni—Ti alloy, which is a shape memory alloy, is fitted to the inner surface of an outer layer material 14 made of gold or a gold alloy via an intermediate material 12. It is fitted on the inner surface of a protective material 15 having a bottomed cylindrical shape made of carbon steel. The round bar core material 11 is made of a Ni-Ti alloy (47-60 at.
om% Ni). Although a Cu—Zn-based alloy also exists as a shape memory alloy, a Ni—Ti-based alloy is used in the present embodiment in consideration of corrosion resistance to sweat, cosmetics, and the like, or lightness.

After adjusting the clad material 1 in a vacuum chamber maintained at a predetermined degree of vacuum, the same material is fixed to the opening of the protective material 15 by electron beam welding.
To form In this way the interior is about 2-3 × 10 ^-4 Torr
The clad material 1 kept in the high vacuum state is formed.
Heat this to 800 ° C and then use an extrusion press to make the outer diameter 20mm
Hot extrusion, and cold drawing and softening annealing at 600 ° C. are repeated to make the outer diameter 8.5 mm. This clad wire is immersed in a hydrochloric acid bath to dissolve and remove the low carbon steel of the protective material 14, exposing the gold alloy layer to the surface, and further, repeating the cold drawing and softening heat treatment to make the outer diameter 1.8 mm to 3.2 mm. Is obtained. FIG. 2B is a schematic sectional view showing the structure at this time.

FIG. 3 is an external perspective view of the eyeglass frame.
The spectacle frame is composed of a rim 21 holding a lens and a temple 22 hung on the ear. FIG. 4A is a cross-sectional structural view showing the structure of the clad material subjected to the rim processing.
(b) is a sectional structural view showing a structure of the temple-processed clad material. The processed clad material is formed into a substantially trapezoidal cross section by roll forming, and further subjected to a rim process in which a groove is provided at the center of one surface. Further, temple processing is performed in which a cross section is formed into a flat elliptical shape by swaging and press molding, and one side is flattened.

Next, the quality of the bonding state, the corrosion resistance and the cold workability of the clad material for an eyeglass frame according to the present invention and the clad material of the comparative example are determined and compared. The material of the outer layer material is examined. The clad material of this embodiment is made of Ni-Ti
For the base alloy, a shape memory alloy having a component composition of Ni: 51 atom%, Ti: 49 atom%, and outer diameter of 55.5 mm is used.
m, a 7 mm thick 18K gold alloy is used, and the material of the intermediate material 12 is a 0.1 mm thick Ta foil, Nb foil or Nb alloy foil.
The protective material 15 is made of low carbon steel having an outer diameter of 78 mm and an inner diameter of 70.5 mm. Table 1 is a table showing combinations of outer layer materials and intermediate materials used for the clad material of the present invention and the conventional comparative material.

[0019]

[Table 1]

First, it was examined how the shape recovery performance varies depending on the cross-sectional area ratio of the outer layer material to the entire clad material. No. 1 shown in Table 1, the core material 11 is Ni
-Ti alloy, intermediate material 12 is Ta, and outer layer material 14 is 18
The cladding material is manufactured by changing the cross-sectional ratio of the outer layer material 14 by the combination of K. After hot extrusion, protective material and 18
After cutting the K, the sectional area ratio of 18K is 10%, 20%, 30%, 33
%, 35% clad material. Die drawing and softening annealing were repeated on these to form an outer diameter of 2.5 mm, and heat treatment was performed at 600 ° C for 10 minutes to obtain a clad wire.

[0021]

[Table 2]

Table 2 shows the results of a shape recovery performance test performed on the five types of clad wires thus obtained. The test was conducted using a tensile tester to pull the clad wire rods to give 2% and 6% plastic strain, respectively, and then the test was conducted at 120 ° C.
Then, the recovery rate of each clad wire is measured. In addition, the same test was performed for the alloy wire having a diameter of 2.5 mm of a single Ni-Ti alloy.

The reason why the shape recovery performance was tested is as follows. Shape memory alloys have functionalities such as shape memory effects and superelastic properties. The greatest feature of the shape memory alloy is that it has a shape memory effect as the name implies, and it has this effect and also exhibits superelastic properties. The present invention is a shape memory alloy clad wire,
Since a different metal is joined to the shape memory alloy, the functional characteristics (shape memory effect, superelasticity, etc.) of the single metal are reduced. Therefore, the degree of the decrease in the functional characteristics due to the use of the clad wire is regarded as important.

When a shape memory alloy is applied to a spectacle frame among ornaments, the superelastic property among the functional properties is used. Since it is difficult to quantify the superelastic properties, we confirmed the shape memory effect with the shape recovery rate,
This confirms the superelastic properties.

As apparent from Table 2 showing the results of the shape recovery rate measured for the above reasons, the 18K
There is a close relationship between the cross-sectional area ratio and the recovery rate of the clad wire, and the recovery rate when a plastic strain of 2% is applied is 70-80% when the cross-sectional area ratio exceeds 30%, but is 30% or less. 90%
It turns out that it is above.

When a plastic strain of 6% is applied, a recovery rate of 70% or more is exhibited when the sectional area ratio is 30% or less, and only a recovery rate of 50 to 60% is exhibited when the sectional area ratio exceeds 30%. .
From these facts, the 18K cross-sectional area ratio of the outer layer material 14 is 30%
The total thickness of the outer layer material and the intermediate material is preferably
The ratio t / D of (t) to the outer diameter (D) of the clad wire is 0.
It can be said that it is preferably from 005 to 0.2.

[0027]

[Table 3]

Next, clad materials No. 1 to 8 are prepared by the combinations shown in Table 1, and clad wires having outer diameters of 3.2 mm and 1.8 mm having a sectional area ratio of 20% are manufactured based on the above results. Table 3 shows the quality of the workability of these wires, the quality of the bonding state at the bonding interface of the clad wire having an outer diameter of 3.2 mm, and the superiority of the corrosion resistance at the interface. The quality of the workability is determined based on the quality of the respective joined states after the rim processing or the temple processing of the clad wire as described above.

The quality of the bonding condition is determined based on the results of observation of the bonding interface with an electron microscope, and the determination of the corrosion resistance is determined by applying a corrosive solution containing salt, acetic acid and copper chloride to each clad wire for a predetermined time. This is performed depending on the quality of the joint after spraying. The tests on the bonding state and the corrosion resistance were performed before heating and after reaching the brazing temperature (900 ° C. or higher) required for assembling to the eyeglass frame, respectively.

In Table 3, ◎ indicates that no defect was confirmed as a result of observation of the bonding interface at 2000 times magnification with an electron microscope, and ○ indicates that several void-like defects, so-called voids, were generated. When confirmed, Δ indicates a case where a large number of voids were generated, and X indicates a case where peeling was confirmed at the bonding interface.

As is apparent from Table 3, Ta is used as the intermediate material.
It can be seen that the clad wire of No. 1 is excellent in all test items. In addition, the clad wires of Nos. 2 and 3 in which the intermediate material 12 was Nb or an Nb alloy had excellent bonding conditions at the interface before and after heating, good after heating, and good corrosion resistance before heating. The workability of the rim and temple is also good. However, deterioration of corrosion resistance was observed after heating, which is considered to be due to the formation of an intermetallic compound having poor corrosion resistance at the Nb or Nb alloy interface.

In order to further examine the influence of heating of the No. 2 clad wire, the heating temperature was changed, and a corrosion resistance test was performed at each temperature. As a result, when the heating temperature exceeds 800 ° C., the corrosion resistance significantly deteriorates, and this deterioration occurs at the interface between the Ti-containing core material 11 and the intermediate material Nb. As described above, in the brazing at the time of assembling the spectacle frame, the temperature near the brazing portion may exceed 900 ° C., and when the No. 2 clad wire is applied to the spectacle frame, the corrosion resistance is deteriorated.

As described above, when the No. 2 clad wire is used as a material for an eyeglass frame, the corrosion resistance is deteriorated by brazing, and the aesthetic appearance is likely to be impaired by long-term use. It can be said that it has sufficient corrosion resistance performance for decorative articles that do not have them.

On the other hand, the No. 4 clad wire using Ni as the intermediate material has good bonding state and corrosion resistance before heating, but after heating, many voids are confirmed at the bonding interface, and the bonding and corrosion resistance are poor. It turns out that it is inferior. Further, those processed into rims and temples were peeled off at the joint interface, and the workability was not good. It can be said that this is because the bonding strength at the bonding interface is not sufficient, and it cannot withstand processing.

Further, when Ni or Zn is used for the intermediate material,
The clad wires of Nos. 5 and 6 did not have any good bonding state, corrosion resistance and workability. And the intermediate material is 50% Ag-
In the case of No. 7 clad wire having 50% Pd, the bonding state at the bonding interface was relatively good before heating, but peeling was observed after heating, and the corrosion resistance was also deteriorated after heating. Moreover, many voids were generated by the rim and temple processing, and the workability was not good.

Further, the clad wire of No. 8 having no intermediate material has the same bonding condition and corrosion resistance at the bonding interface as those of Nos. 5 and 6, and some have been peeled off by rim and temple processing, and have sufficient workability. Hard to say good.

From the above, No. 1 clad wire is
The workability of each component of the spectacle frame, the bonding state after brazing, and the corrosion resistance are excellent, and it is suitable as a material for other spectacles as well as a material for spectacle frames. Since Ta has a higher melting point than Nb, the initial diffusion rate of metal atoms at the bonding interface during heating is lower than that of Nb, and the thickness of the generated intermetallic compound is thin. For this reason, with respect to the corrosion resistance, Ta is preferable to Nb for the intermediate material 12, but for the decorative article formed without brazing, the bonding interface state after cold working is excellent. No. 2 and 3 clad wires can also be used as decorative materials.

In this embodiment, Ta, Nb is used as the intermediate material.
Alternatively, although Nb-1% Zr is used, the invention is not limited to this, and a Ta alloy or an Nb alloy containing 90% or more of Ta or Nb may be used.

As described above, the decorative article is manufactured from a complicated shape such as an eyeglass frame in which various cold-worked parts are assembled by brazing, and then subjected to a surface treatment after the cold work. Since even a relatively simple shape such as a bracelet exists, the clad wire of the present invention can select and apply the intermediate material 12 according to the type and use of the decorative article, and makes use of the superelastic effect. By doing
It is possible to make the decoration flexible and fit to the body.

Next, a specific description will be given based on the drawings showing a second embodiment of the present invention. FIG. 5 is a schematic longitudinal sectional view showing the structure of a clad material for a gold-clad wire according to a second embodiment of the present invention. FIG. 6A is a cross-sectional structural view taken along line VI-VI in FIG. The cladding material 5 is a shape memory alloy N
A round bar core material 51 made of an i-Ti alloy is fitted on the inner surface of the intermediate material 52, and this is passed through a metal outer layer material 53, which is a second layer of the outer material, to form a first gold or gold alloy material. Outer layer material 54 of layer
Are further fitted on the inner surface of a protective material 55 having a bottomed cylindrical shape made of low carbon steel. For the round bar core material 51, a Ni—Ti alloy component material is Ni: 51at.
om%, Ti: 49 atom%, and an outer diameter of 49.9 mm using a Ni-Ti based shape memory alloy, and the outer layer material 53 of the second layer is made of a metal that does not rust in air, for example, a pure Ni tube. 57.7m in diameter
m, having an inner diameter of 50.3 mm. The first outer layer material 54 made of a gold alloy tube has an outer diameter of 60 mm and a thickness of 60 mm.
A 0.6 mm 75% Au-12.5% Ag-12.5% Cu 18K alloy tube is used. The protective material 55 has an outer diameter of 67.0 mm and an inner diameter of 6 mm.
Use 0.5mm low carbon steel pipe.

After adjusting the clad material 5 in a vacuum chamber maintained at a predetermined degree of vacuum, the same material is fixed to the opening of the protective material 55 by electron beam welding.
To form Then, in the same manner as in the first embodiment,
Cold drawing and softening heat treatment are repeated on the clad material 5,
Obtain a clad wire with an outer diameter of 1.8 to 3.2 mm. Fig. 6 (b)
Is a cross sectional structural view showing the structure at this time.

As shown in FIG. 4 (b), such a clad wire was subjected to temple processing and bridge processing by swaging and press forming, and an eyeglass frame was assembled using this. After the temple processing and the bridge processing, the bonding state of the brazed portion was observed using an electron microscope. As a result, no defect such as a void was observed at each bonding interface, and the bonding state was good.

Using the clad wire, decorative articles of various shapes such as bracelets were processed. As a result, no defects such as peeling at the bonding interface occurred, and good workability was exhibited. Further, a gold clad wire was produced using an Nb foil instead of the Ta foil of the second embodiment, and processed into a decorative article such as a bracelet. As a result, no defects occurred at the bonding interface, and good workability was exhibited.

From the above, when the clad wire of the second embodiment is used for the decorative article including the spectacle frame, the super elastic effect which is the characteristic of the shape memory alloy material is utilized to make the body extremely supple and to the body. A decorative article that can be fitted can be formed, and gold or gold alloy as the outer layer material of the first layer is thinned,
Cost can be reduced. Moreover, since the metal which does not rust in the air is used for the outer layer material of the second layer, the exposed portions of the temples or bridges of the spectacle frame do not rust.

In the second embodiment, the outer layer material 5 of the second layer is used.
3, a pure Ni tube is used, but the present invention is not limited to this, and a Ni-based alloy, a pure Cu tube, a Cu-based alloy or a Co-based alloy may be used, and 90% Ni-7% Cr-1% Al Ni
Base alloy, 65% Cu-20.5% Ni-4% Sn-4% Pb-
Cu-based alloy of Zn or 41% Co-39.3% Ni-16.8% C
A decorative article having a good appearance was processed using a Co-based alloy of Vr2.5% Mo.

In this embodiment, a Ni-Ti alloy is used as the shape memory alloy of the core material. However, the present invention is not limited to this, and a Cu-Zn alloy may be used.

[0047]

As described above, in the present invention, the core is a shape memory alloy, the outer layer is made of gold or a gold alloy, and Ta, Nb or their alloys are interposed between them. , Has a metallic luster on the surface, further enhances workability, can easily perform polishing, plating, brazing, etc.,
It can be used as a material for decorative articles including eyeglass frames. In addition, the outer layer material includes a first layer made of gold or a gold alloy and Ni. Since the present invention is composed of the second layer made of a Ni-based alloy, Cu, a Cu-based alloy, or a Co-based alloy, the present invention has excellent effects such as the amount of gold or gold alloy used can be adjusted. .

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing the structure of a clad material for a clad wire according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional structural view taken along line II-II in FIG. 1, and FIG. 2B is a cross-sectional structural view of a clad wire of the first embodiment.

FIG. 3 is an external perspective view of an eyeglass frame.

FIG. 4A is a cross-sectional structure diagram showing a structure of a rim-processed clad material, and FIG. 4B is a cross-sectional structure diagram showing a structure of a temple-processed clad material.

FIG. 5 is a schematic longitudinal sectional view showing a structure of a clad material for a clad wire according to a second embodiment of the present invention.

6A is a cross-sectional structural view taken along line VI-VI of FIG. 5, and FIG. 6B is a cross-sectional structural view of a clad wire of the second embodiment.

[Explanation of symbols]

 11,51 core material 12,52 intermediate material 14 outer layer material 53 second layer outer layer material 54 first layer outer layer material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B32B 15/01 C23C 28/02 G02C 5/00 C22C 19/03

Claims (2)

(57) [Claims] 1. A core material made of a shape memory alloy and an outer layer material made of gold or a gold alloy covering the outer periphery thereof, wherein Ta, Nb or an alloy thereof is interposed between the core material and the outer layer material. A clad wire comprising: 2. The outer layer material comprises an outer first layer made of gold or a gold alloy and an inner second layer made of Ni, a Ni-based alloy, Cu, Cu-based alloy, or a Co-based alloy. The clad wire according to claim 1, wherein: