JPH0299218A - Manufacture of titanium composite material - Google Patents

Abstract

PURPOSE:To obtain the composite material having a smooth surface by forming a metal spraying layer of titanium (alloy) on the surface of a core metal, loosely fitting into a capsule to pack metal powder and to vacuum-seal and press working, sintering the metal powder, after wire drawing through hot extrusion, removing the capsule. CONSTITUTION:The thermal spraying layer 2 and sintering layer 3 are formed on a surface of a core metal 1. The core metal 1 consists of titanium and the sintering layer 3 consists of nickel (alloy). The thermal spraying layer 2 consists of molybdenum, etc., further, as providing the 2nd thermal spraying layer 2b consisting of copper, the joining strength is improved more over. The core metal 1 forming with the thermal spraying layer 2 is inserted into the capsule made of mild steel, after packing nickel (alloy) powder between the core metal and capsule, this is vacuum-sealed to form by a cold isostatic pressing. Then, the sintering layer 3 heated in prescribed temp. and time is sintered to join each layer. After that, the hot extrusion working is performed and the capsule of the most outside layer is removed to make to the titanium composite material. By this method, the titanium composite material having the smooth surface without generating any wrinkle and high mechanical strength is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a titanium composite material suitable for use in eyeglass frames, etc., and is capable of producing a titanium composite material with a smooth surface and high bonding strength. It is.

[Prior art and its problems] Titanium or titanium alloy is a material with excellent corrosion resistance.
In addition, because it is lightweight and has high strength, it has recently attracted attention as a material for eyeglass frames such as high-end sunglasses. However, titanium or titanium alloy has poor brazing properties and plating properties, which are essential in the manufacturing process of eyeglass frames. Conventionally, to solve this problem, titanium composites and titanium composites have been developed, which are made by cladding copper alloys or nickel alloys with good brazing and plating properties on the surface of a core material made of titanium or titanium alloys. Those whose surfaces are plated with precious metals have been widely used.

To manufacture such a titanium alloy composite material, a core material made of titanium or a titanium alloy is fitted into a pipe made of a nickel alloy or copper alloy, which will serve as a sintered layer, and this is vacuum sealed. A manufacturing method is used in which a core material and a sintered layer are clad-bonded by hot isostatic pressing (HIP), and then wire drawn by isostatic extrusion to produce a titanium composite material.

However, in this manufacturing method, it is absolutely necessary to provide a certain amount of space between the core material and the sintered layer when fitting the core material into the sintered layer. There was a problem in that the gaps caused wrinkles on the surface of the sintered layer during hot isostatic pressing for clad bonding. Furthermore, the shape of the core material housed inside the sintered layer is formed along the inner wall surface of the sintered layer, so if you try to remove the wrinkles that have occurred on the surface of the sintered layer, the wrinkles on the surface of the sintered layer will be removed. It was difficult to remove wrinkles generated on the surface of the sintered layer because the core material that had been deformed along the shape had to be cut together. Furthermore, although it is possible to disperse these wrinkles during wire drawing, there is a problem in that the manufacturing process becomes extremely complicated if the wire drawing process that involves the dispersion of wrinkles is performed consecutively with the clad bonding process.

Furthermore, since the process of fitting the core material into the sintered layer is done manually, dirt tends to adhere to the surface of the core material, and this dirt causes poor bonding between the core material and the sintered layer, resulting in expansion. There was a problem in that the core material and the sintered layer peeled off during wiring.

This invention was made in order to solve the above problems, and the purpose is to provide a manufacturing method that can easily produce a titanium composite material with a smooth surface and no peeling between the core material and the sintered layer. It is said that

[Means for Solving the Problems] This invention involves forming a thermal spray layer on the surface of a core material made of titanium or a titanium alloy by a metal spraying method, loosely inserting this layer into a capsule, and then forming a spray layer between the core material and the capsule. The solution is to fill the capsule with metal powder, vacuum seal the capsule, mold it by cold isostatic pressing, sinter the metal powder, draw it by hot extrusion, and then remove the capsule. It was used as a means.

[Function] A sprayed layer is formed on the surface of the core material, this is inserted into the capsule, and metal powder, which will become the outermost layer of the titanium composite material, is filled between the core material and the capsule. It is possible to prevent wrinkles from occurring on the surface of the titanium composite material due to deformation of the gap existing between the powder and the metal powder.

In addition, each material to be bonded to the core material is in powder form and is sintered to form a titanium composite material, so that sufficient bonding between each material can be achieved and a titanium composite material with high mechanical strength can be obtained. be able to.

The present invention will be described in detail below.

FIG. 1 shows an example of a titanium composite material obtained by the manufacturing method of the present invention.

This titanium composite material has a thermal spray layer 2 and a sintered layer 3 on the surface of the core material 1.
It is formed by forming. The core material 1 is made of titanium or a titanium alloy, and the sintered layer 3 is made of nickel or a nickel alloy that exhibits excellent brazing and plating properties with various metals.

The sprayed layer 2 joins the core material 1 and the sintered layer 3, and is made of an intermetallic compound that can easily form a solid solution by diffusion with the titanium constituting the core material 1, and which reacts with titanium and exhibits brittleness. It is made of molybdenum, niobium, tantalum, or an alloy of two of these metals, which are difficult to generate. Moreover, this thermal spray layer 2
As shown in the figure, a second sprayed layer 52b made of copper or a copper alloy may be provided on the first sprayed layer 2a made of the metal or alloy. A second thermal spray consisting of copper or copper alloy E! By providing I2b, the bonding strength between the core material 1 and the sintered layer 3 can be further improved. Moreover, the thermal spray layer 2 is 3 or more 11r11. It may also be formed from fgJ.

The following steps are used to manufacture such a titanium composite material.

The core material 1 made of titanium or titanium alloy billet is subjected to pre-spraying treatment such as shot blasting to remove foreign matter on its surface, and then molybdenum, niobium,
A thermal spray fm2 made of tantalum or an alloy of these two is formed. The metal spraying method at this time is preferably a plasma cold spraying method in which oxides are less likely to be mixed into the sprayed powder, and the raw material thereof is preferably a gas atomized powder with a particle size of 30 to 75 μm. The thickness of the sprayed layer 2 is appropriately selected depending on the diameter of the core material, the thickness of the sintered layer 3, and the intended use of the titanium composite material to be manufactured. When the thermal spray layer 2 is composed of two thermal spray layers as shown in FIG. The second thermal sprayed layer 2b can be continuously formed on the first thermal sprayed layer 2a by thermal spraying in exactly the same manner as when forming the layer 2a. Furthermore, even when the thermal sprayed layer 2 is composed of two or more layers, the second thermal sprayed layer 2b is formed on the first thermal sprayed layer 2a in exactly the same manner as the second thermal sprayed layer 2b is formed on the first thermal sprayed layer 2a. Multiple sprayed layers can be stacked on top of each other.

The sprayed layer 2 thus formed is porous and close to a powder state. Therefore, during hot extrusion processing, which will be described later, the metal powder constituting the sprayed layer 2 deforms and enters the gaps between the metal powders and is plastically deformed, which prevents wrinkles from forming on the surface of the sintered layer 3. It can be prevented.

Next, the core material 1 on which the sprayed layer 2 has been formed is inserted onto the central axis of the capsule made of mild steel. This capsule is made of a core material l on which a thermal sprayed layer 2 is formed so that a gap sufficient to fill the metal powder constituting the sintered layer 3 is created between the core material 1 inserted into the capsule and the capsule. It consists of a bottomed cylindrical pipe with a diameter larger than the diameter of the pipe.

After filling the gap created between this capsule and the core material 1 inserted into the capsule with metal powder constituting the sintered NJ3, this is sealed and cold isostatically pressed (CIP).
). As the metal powder, nickel or a nickel alloy having good brazing and plating properties with various metals is suitable. Then, heating is performed at 800 to 900° C. for 1 to 2 hours to sinter the sintered layer 3 and join the core material 1, the sprayed layer 2, and the sintered layer 3 together. Through this sintering, the volume of the sprayed layer 2 and the sintered layer 3 is reduced and a dense structure is formed, so the core material 1, the sprayed layer H2, and the sintered layer 3 are bonded with high bonding strength. .

In addition, the sintered layer 3 is the outermost layer of the titanium composite, and because it is formed by sintering, it has a smooth and beautiful surface, unlike titanium composites obtained by conventional manufacturing methods. becomes.

After sintering the sintered layer 3 in this manner, it is subjected to hot extrusion and the outermost layer capsule is removed to obtain a titanium composite material. This hot extrusion processing is not particularly limited as long as it is a commonly used processing method, but it is approximately 600°
C11-800-90 after preheating for 2 hours
Hot extrusion at 0°C is preferred. Core material 1 and thermal spraying H
Since the sintered layer 2 and the sintered layer 3 are bonded with sufficient bonding strength by the above-mentioned sintering process, separation between the layers does not occur during this wire drawing process. The method for removing the capsule from the titanium composite material is not particularly limited, and can be carried out using a stripper or the like that is normally used in the process of stripping wire rods.

The titanium composite material obtained in this way is prepared by providing a powder sprayed layer 2 on the surface of the core material 1, inserting this into the nop cell, and then inserting the metal that will become the sintered layer 3 between the capsule and the core material 1. Since the capsules are removed after filling powder, sintering them, and wire drawing, it is possible to bond the layers that make up the titanium composite with sufficient strength, so the resulting titanium composite The material exhibits high mechanical strength.

Furthermore, since the sintered layer 3, which is the outermost layer of the titanium composite material, is formed by sintering metal powder, its surface is wrinkle-free and smooth and beautiful.

Furthermore, since the outermost layer of the titanium composite material obtained in this way is made of sintered B3 of nickel or nickel alloy,
The surface may be plated with gold or silver depending on the purpose.

[Example] (Example) A titanium billet with a diameter of 92 mm and a length of 1000 mm was prepared as a core material, and after surface treatment was performed by shot blasting, the surface was coated with an average particle size of 30 to 75 μm.
A molybdenum sprayed layer having a thickness of 05 mm was formed by a plasma cold spraying method using molybdenum gas atomized powder. Then, on this molybdenum sprayed layer, an average particle size of 45~
A copper sprayed layer having a thickness of 0.5 mm was formed by plasma cold spraying using 90 μm copper gas atomized powder.

After this was inserted onto the central axis of a capsule made of mild steel with an inner diameter of 97+m and a wall thickness of 3IIIffi, the gap between the capsule and the core material was filled with alloy powder made of a nickel-chromium alloy and vacuum-sealed. This was molded by cold isostatic pressing using O, IGPa, and then heated at 800 to 900° C. for 1 hour to sinter each layer. And this 600°C
After preheating for 1 hour at
The wire was drawn to m. Thereafter, the outermost layer of the capsule was removed to obtain a titanium composite material.

All of the obtained titanium composite materials had smooth surfaces with no wrinkles.

Five titanium composites were selected from the titanium composite materials thus obtained, and test pieces as shown in FIGS. 3 and 4 were prepared. FIG. 3 is a plan view of this test piece, and FIG. 4 is a view of the test piece taken along the line IV-IV.

This test piece was made by cutting the titanium composite material into a length of 20fflI11, and then removing the thermal spray layer and the sintered layer so that a test protrusion with a length of 3n+m was formed on the surface of the titanium composite material.
This shows the core material of m.

Then, as indicated by the symbol F in FIG. 4, a force was applied in a direction to separate the test protrusion from the core material, and the shear strength at break was measured. The results are shown in Table 1 below.

(Comparative example) A titanium billet with a diameter of 92 mff1 and a length of 1000 mm was used as a molybdenum pipe with an inner diameter of 92 ffiffi and a wall thickness of 0.5 mm, a copper pipe with an inner diameter of 92.5 mm and a wall thickness of 0.5 mff1, and a nickel-chrome pipe with an inner diameter of 93 mm and a wall thickness of 31 mm. After sequentially fitting into the alloy vibrator, 1.
These were clad-bonded by heating and pressurizing at 000° C. and 180 MPa for 2 hours. Then, the wire was drawn under pressure at 900 MPa using a hydrostatic extruder to obtain a wire with a diameter of 60ffi111.
titanium composite material was obtained.

Five titanium composites were selected from the titanium composite materials obtained in this way, and test pieces were prepared in exactly the same manner as in the example.
The fracture shear strength of the test piece was measured. The results are also shown in Table 1.

The breaking shear strength (GPa) shown in Table 1 is the breaking load (kg) at which the test protrusion of the above test piece peeled off from the core material.
is divided by the area of the test protrusion (IIlm'').

From the results shown in Table 1, it is clear that according to the titanium composite manufacturing method of the present invention, titanium composites with a smooth and beautiful surface without wrinkles can be easily obtained, and the bond between the core material and the sintered layer can be easily obtained. It was confirmed that the strength could be improved.

[Effects of the Invention] As explained above, the method for producing a titanium composite material of the present invention involves forming a sprayed layer on the surface of a core material made of titanium or a titanium alloy by a metal spraying method, and then loosely inserting this into a capsule. , filling the space between the core material and the capsule with metal powder 11, vacuum sealing the capsule and molding it by cold isostatic pressing, then sintering the metal powder, and drawing it by hot extrusion. Since the capsule is removed, a titanium composite material with a smooth and beautiful surface without wrinkles can be obtained.

In addition, since each layer is joined by sintering and wire drawing is performed by hot extrusion processing, the joining strength between the core material and the sintered layer can be improved, and a titanium composite material with high mechanical strength can be obtained. Can be done.

[Brief explanation of the drawing]

Figures 1 and 2 are both schematic cross-sectional views showing an example of a titanium composite obtained by the titanium composite manufacturing method of the present invention, and Figures 3 and 4 are fracture shear diagrams of the titanium composite. Figure 3 is a plan view, and Figure 4 is a view taken along the line ■■ in Figure 3. ... core material, 2 ... thermal spray layer, 3 ... sintered layer.

Claims (1)

[Claims] A sprayed layer is formed on the surface of the core material made of titanium or titanium alloy by a metal spraying method, and after this is loosely inserted into the capsule, metal powder is filled between the core material and the capsule, and the capsule is vacuum sealed. A method for producing a titanium composite material, which comprises: forming the titanium composite material by cold isostatic pressing, then sintering the metal powder, drawing the metal powder by hot extrusion, and then removing the capsule.