JPS6378741A - Composite material for spectacle frame - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite material for eyeglass frames in which Ti or a Ti alloy is used as a core material and Ni or a Ni-based alloy with excellent corrosion resistance is used as an outer skin material.

[Conventional technology] The materials used for eyeglass frames must be: ■ light in weight, ■ have a suitable strength that is easy to process but difficult to deform due to handling errors, and ■ is durable against corrosion and discoloration. Performance such as having the following characteristics is required. Incidentally, Ti or a Ti alloy (hereinafter sometimes simply referred to as Ti) is a metal material that satisfies strict properties, and has long been attracting attention as the most excellent material for eyeglass frames. However, in reality, it took a long time before Ti was widely used as a metal material for eyeglass frames. This is because Ti has difficulties in brazing properties, surface treatment, etc.
In particular, it was difficult to process the hinge part because brazing was difficult.

However, in recent years, composite materials with Ti as the core material and a corrosion-resistant metal cladding on the surface have been developed, and it has become possible to perform brazing and surface treatment using the same methods as conventional materials. Nowadays, eyeglass frames are being supplied in cloth.

Such composite materials include: ■A double structure in which the surface of a Ti core material is clad with a highly corrosion-resistant Ni or Ni-based alloy as an outer skin material, or ■A structure in which Nt is clad between a Ti core material and a noble metal skin material. A triple-layered structure with an intermediate layer interposed therebetween, etc., is known.

[Problems to be Solved by the Invention] These composite materials are excellent in terms of ease of brazing between the composite materials and aesthetic appearance as a sacrificial item, but in view of the characteristics of the clad material, there are problems during heat treatment and Special consideration was required when the child became deaf. In other words, eyeglass frames are generally heat treated to make the material soft or hard depending on the design, but there are restrictions such as not affecting the interfacial strength between the outer skin material and the core material. Therefore, the tempering temperature range was naturally limited. In addition, each part of an eyeglass frame is affected by heat from high temperatures during brazing, so the interface is likely to deteriorate, and the conditions for brazing are severely restricted, and in some cases, there are problems such as defective brazing in some parts. Ta.

The present invention was made to solve the above-mentioned problems, and its purpose is to provide a composite material configured so that the interfacial strength will not deteriorate as much as possible due to thermal effects during heat treatment and brazing. It's about doing.

[Means for solving the problems] The present invention that achieves the above object is based on a core material made of Ti or Ti.
This composite material for eyeglass frames is characterized in that the core material surface is coated with an intermediate layer made of Nb, and the surface of the intermediate layer is further coated with Ni or a Ni-based alloy.

[Function] The present invention is constructed as described above, but the point is that it is a composite material for eyeglass frames having Ti or a Ti alloy as a core material and Ni or a Ni-based alloy as an outer skin material, wherein the core material and the outer skin material The greatest feature is that Nb is interposed as an intermediate layer between the two.

The present inventors conducted various studies to achieve the above object, and found that the reason why the interfacial strength of Ni-Ti composites deteriorates due to thermal effects is that Ni, which is the outer skin material, is the core material. It was found that this is because Ti diffuses into Ti and forms an intermetallic compound, which has a negative effect on the interfacial strength.

Therefore, the present inventors carried out further research based on the idea that if the diffusion of Ni could be suppressed, it would be possible to prevent the deterioration of the interfacial strength due to thermal effects.
The present inventors have discovered that the above object can be successfully achieved by interposing an Nb intermediate layer between the i-core material and have completed the present invention.

The inventors have confirmed through experiments that in conventional Ni-Ti composite materials, Ni diffuses into Ti even after a light heat treatment of about 650°C for about 5 minutes, and the interface of the composite material Deterioration in strength had occurred.

However, in a Ni-Nb-Ti composite material in which a Nb intermediate layer is interposed between a Ti core material and a Ni outer skin material,
No deterioration in the interfacial strength was observed even after heating for 5 minutes, thus proving that Nb has the effect of suppressing the diffusion of Ni into Ti.

Note that the composite material constructed according to the present invention is manufactured, for example, in the following manner. That is, the surface of the Ti core material is coated with Nb as an intermediate layer, and the surface of this intermediate layer is further coated with a Ni outer skin material to create a composite billet. After hot isostatically extruding the composite billet at a temperature, the present invention will be explained in more detail with reference to examples.

First, the present inventors created a composite billet having a structure as shown in FIG. As shown in Fig. 1, a cylindrical Ti core material 1
A Nb intermediate layer 2 (thickness 0.5 mm) is formed in a cylindrical shape on the radially outer side of the (outer diameter 64 mm), and a Ni outer skin material 3 (outer diameter 68 mm + inner diameter 65 mm) is formed radially outside the intermediate layer 2.
mm+) was formed into a cylindrical shape. The length of the composite billet consisting of Ti core material 1, Nb intermediate layer 2 and Ni outer skin material 3 is 15
0 mm, and the mutual relationship between the Ti core material 1, the Nb intermediate layer 2, and the Ni outer skin material 3 was set to be 0.1 to 0.2 mm.

In FIG. 1, reference numerals 4 and 5 indicate dummy blocks (cupronickel) placed at both ends in the axial direction (both ends in the left and right direction in FIG. 1) of the composite billet. The end portion of the outer skin material 3 is welded and fixed to. When the composite billet is assembled as shown in Figure 1, the intervening air between each layer must be removed via the degassing pipe 6.
(approximately 10-2 Torr) and then sealed.

The composite billet, which has been degassed and sealed, is heated to 750°C and extruded into a 16 mm bar by hot isostatic extrusion, and then cold drawing and annealing are repeated to obtain a diameter of 2.6 mm+.
After processing it into a wire rod, press it to a thickness of 1.5mm.
The wire rod was flattened so that The thickness of the Nb intermediate layer 2 is 2 when the wire has a diameter of 2.6 mm+.
It was 0μ. For comparison, a composite billet was also produced in the same manner when the initial thickness of the Nb intermediate layer 2 was set to 0.08 mm. And at this time, the diameter is 2.6
The thickness of the Nb intermediate layer 2 when it was made into a wire of m+a* was 1 μ.

The wire rods thus obtained were brazed with BAG-7 to prepare test pieces, and then thermal histories at various temperatures were added to the test pieces to measure the shear strength of the brazing parts.

The results are shown in Figure 2. For comparison, Figure 2 shows the product of the present invention (Ni-Nb-Ti composite) and the conventional product (Nl-Ti composite) prepared in the same procedure. The results are also included.

As is clear from the results in Figure 2, the conventional product has a
The interfacial strength obtained by heat treatment at 850°C for 5 minutes was maintained in the product of the present invention even when heated at 850°C for 5 minutes, clearly showing that the heat resistance of the composite material was improved.

Furthermore, the present inventors conducted line analysis of component elements on a cross section of a test piece of the present invention subjected to thermal history (EPMA). As a result, as shown in Figure 3 (1), no diffusion of Ni into Ti was observed in the composite material with high interfacial strength (heated at 600°C for 5 minutes), whereas in the composite material with low interfacial strength (heated at 600°C for 5 minutes) 800t
As shown in Figure 3 (2), in the case of
It was observed that there was a tendency for Nb itself to diffuse into Ti as well as to pass through it and diffuse into Ti. This result suggests that the diffusion of Ni into Ti has a large effect on the deterioration of the interfacial strength of the composite material.

In order to support the above results, the present inventors created another composite material and investigated its properties. That is, as the outer skin material 3, N
A composite billet as shown in FIG. 1 was prepared using a Ni-based alloy of i-3% Co-3% Cr, and the same evaluation tests as in the previous example were conducted. The outer skin material 3 has an outer diameter of 144 m.
The inner diameter is 130 mm, the length is 700 mm, and the Nb
The thickness of the intermediate layer 2 was 0.06 mm% Ti, and the outer diameter of the core material 1 was 128 mm.

After degassing and sealing such a composite billet, it was heated at 700°C, extruded into a 29 mm+ bar by hot isostatic extrusion, and then cold drawn and annealed repeatedly to make a bar with a diameter of 2.6 mm.
A test piece was obtained by processing it into a wire rod of mm diameter. The shear strength of the brazed portion of the obtained test piece was measured in the same manner as in the above example. As a result, the same tendency as in the above example was observed.

Furthermore, analysis of Co and Cr elements using EPMA revealed that the heating material [Figure 4 (1)] and a
No diffusion of Co or Cr into Ti was observed in any of the materials heated at OO°C for 5 minutes [Fig. 4 (2)], and even when Ni-based alloy was used as the outer material 3, high-temperature heat was not observed. It has been found that it is the diffusion of Ni into Ti that deteriorates the interfacial strength due to history.

Although the above-mentioned examples described the results when Ti was used as the core material 1, similar results were obtained when a Ti-based alloy was used as the core material 1.

[Effects of the Invention] As described above, according to the present invention, by adopting the above-described configuration, it is possible to minimize the decrease in the interfacial strength of the composite material due to the thermal effects during heat treatment and brazing. It has become possible.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing the structure of a composite billet constructed according to the present invention, Fig. 2 is a graph showing the relationship between processing temperature and shear strength in the composite material, and Fig. 3 (1), (
2) and FIGS. 4(1) and 4(2) are graphs showing the results of line analysis by EPMA of various composite materials subjected to thermal history. 1...Core material 2...Middle layer 3...Outer skin material 4.5...Dummy block view ζ-

Claims (1)

[Claims] A composite for eyeglass frames, characterized in that the core material is Ti or a Ti alloy, the surface of the core material is coated with an intermediate layer made of Nb, and the surface of the intermediate layer is further coated with Ni or a Ni-based alloy. Material.