JPH08215861A - Joining method for amorphous alloy thin strip - Google Patents

Abstract

PURPOSE: To obtain an amorphous bulk body with high density and high strength by joining amorphous alloy thin strips. CONSTITUTION: An amorphous alloy thin strip with a pressure of 30MPa or higher applied is heated and raised in temperature by energizing with a frequency of 100Hz-100kHz; then held for 1-20 minutes at a temperature 10-150 deg.C lower than the chrystallizing temperature; and mutually joined so as to obtain a bulk joined body. The amorphous alloy thin strip thus used contain 40-90 atomic % Fe, 50-90 atomic % Co or 80-90 atomic % Al. As a result, when joined under the conditions specified with the joining temperature as a reference, the amorphous alloy thin strips are joined with each other without causing interlayer separation or crystallization, improving the density and strength of the bulk body thus obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining an amorphous alloy ribbon while maintaining an amorphous structure.

[0002]

2. Description of the Related Art Amorphous alloys are manufactured by quenching and solidifying a molten alloy, and the usual melting / casting method cannot be adopted. Therefore, the form of the obtained amorphous alloy is also limited to a ribbon or powder. As a means for obtaining a bulk from such a form, there are a method of joining and integrating a plurality of ribbons, a method of sintering powder, and the like. In the sintering method, a bulk is manufactured by sintering an amorphous alloy powder under a high pressure at a temperature equal to or lower than a crystallization start temperature. At this time, if the amorphous alloy powder is heated to a sufficiently high temperature that the densification proceeds due to the plastic deformation of the powder particles and the thermal diffusion of the constituent elements, the crystallization reaction proceeds and the physical properties of the obtained sintered body deteriorate. To do. Therefore, the sintering temperature must be set low,
A sintered body having high density and high strength could not be obtained.

In the method of joining amorphous alloy ribbons into a bulk, the temperature at the time of joining becomes a problem. Generally, joining at low temperature is very difficult, and the obtained bulk body cannot secure sufficient strength. When the joining temperature is set to a high temperature, crystallization occurs and the physical properties of the obtained bulk body are deteriorated. Therefore, the amorphous alloy ribbon is adhered using an adhesive such as a resin, and the relative density of the bulk body is very low, so that the industrial characteristics are not satisfied.

[0004]

As described above, there are many problems in both the sintering method and the joining method. In particular, for amorphous alloy materials that require molding at a temperature lower than the crystallization start temperature, the excellent characteristics inherent to the amorphous alloy tend to be impaired by crystallization, etc., and products that satisfy industrial requirements should be provided. Hard to get. However, in recent years, when the needs for various functional materials have increased, it is desired that bulk-shaped amorphous alloy members also have excellent characteristics. Therefore, a plasma discharge bonding method using a plasma discharge phenomenon by high-frequency energization or the like is desired. Is attracting attention. With this method, bonding for a short time is possible, and the thermal effect on the material is significantly reduced. Further, since the surface oxide film layer is removed by plasma or the like generated between the ribbons, the bonding strength is also improved.

However, in general, in plasma discharge bonding, materials are bonded by controlling current and voltage. In this respect, the amorphous alloy has different electric resistance depending on the material. Therefore, even if the same voltage is applied, the temperature rising rate of the material is different, and as a result, it becomes difficult to keep the bonding temperature constant. Further, the crystallization temperature of an amorphous alloy greatly differs depending on the composition, and the material properties change remarkably due to crystallization, so strict temperature control is required at the time of joining.
The present invention has been devised to meet such a requirement, and by controlling the conditions of high frequency bonding in relation to the physical properties of the amorphous alloy, the thermal effect on the amorphous alloy material is eliminated as much as possible. Then, an object is to obtain a high-density and high-strength joined body in which a plurality of amorphous alloy ribbons are efficiently joined in a short time.

[0006]

In order to achieve the object, the joining method according to the present invention is applied to an amorphous alloy ribbon, to which a pressure of 30 MPa or more is applied, at a frequency of 100 Hz to 100 kHz.
The temperature is raised by heating by energization of z, and the temperature is 10-15
It is characterized in that the amorphous alloy ribbon is held at a temperature lower by 0 ° C. for 1 to 20 minutes. Fe: 40-9 in the amorphous alloy ribbon
0 atomic%, Co: 50 to 90 atomic% or Al: 80 to 9
Those containing 0 atom% are used.

[0007]

The present inventors have found that when joining an amorphous alloy ribbon by supplying a high-frequency current, when the joining conditions are controlled based on the joining temperature instead of the applied current or voltage, the characteristics of the joined body are It was found to be uniform. The present invention has been completed based on this finding, and has established the optimum conditions necessary for obtaining a dense and high-strength amorphous alloy bulk without causing crystallization. Further, when the frequency of the applied current is properly controlled, the efficiency of energy consumed for bonding is improved, the bonding strength between the ribbons is increased at the time of bonding due to the skin effect, and the precipitation of the crystal phase is suppressed. I found a thing. Under these conditions, it was clarified that a high-density bulk-like bonded body can be manufactured without changing the amorphous structure at the time of starting by specifying the bonding pressure and energization time as the bonding conditions.

The amorphous alloy ribbons to be joined are filled in a mold having a prescribed internal shape and then joined by supplying a prescribed high frequency current under pressure. If the frequency of the high-frequency current is 100 Hz or higher, a phenomenon generally called a skin effect occurs, and the current mainly flows on the surface of the ribbon. At this time, due to the contact resistance on the surface of the ribbon and the resistance due to the surface oxide film, the heat generation on the surface portion becomes large and the bonding reaction is accelerated. Since the pressure is applied in this state, the relative density of the joined bulk body is improved. The relative density of the bulk body is significantly improved when the applied pressure is set to 30 MPa or more. In the joining method according to the present invention, unlike the conventional method in which the entire material is uniformly heated and joined, heat is concentrated on the surface portion and the peripheral portion of the amorphous alloy ribbon, and almost no heat is generated inside. Therefore, the heat generated by energization is efficiently consumed for joining the amorphous alloy ribbons, the energization time can be set to an extremely short time, and the amorphous structure is not deteriorated.

Further, the oxide film on the surface of the amorphous alloy ribbon is destroyed by the rapid heating and discharge, and the surface state becomes highly active. The fact that the oxide film is destroyed by the rapid heating and the discharge between the ribbons is confirmed by the fact that no inclusions such as oxides are observed at the bonding interface when the obtained bulk body is observed. Also in this respect, the bonding reaction is promoted and a bulk body having high bonding strength can be obtained. In addition, since the amorphous alloy ribbons are bonded under pressure, the density of the obtained bonded body is also improved. The frequency of the applied current is set in the range of 100 Hz to 100 kHz in order to improve the energy efficiency at the time of joining, increase the joining strength between the ribbons at the time of joining due to the skin effect, and suppress the precipitation of the crystal phase. If the frequency is less than 100 Hz, plasma discharge or the like generated between particles is weak and the oxide film on the surface of the ribbon cannot be sufficiently removed. As a result, the bonding reaction between the ribbons is not promoted, and a bonded body with poor bonding strength is obtained. Conversely 1
A frequency over 00 kHz requires special equipment and adversely affects peripheral equipment such as radio interference.

As a device used for high-frequency power supply, there is a high-frequency current generator capable of outputting a predetermined electric power. In order to supply a high current at a high voltage for a short time, for example, a capacitor that withstands a predetermined voltage is charged with electricity, and the charged power is discharged to an amorphous alloy ribbon which is a material to be joined. Alternatively,
It is also possible to supply a high current at a high voltage for a short time using a pulse current generator. At the time of energization, it is necessary to press the amorphous alloy ribbon at a pressure of 30 MPa or higher in order to improve the relative density of the obtained joined body. By this pressurization, the surface oxide film is removed, and the surface is heated and softened by Joule heat, so that the amorphous alloy ribbons are tightly bonded to each other to form a high-density bonded body.
When the applied pressure is less than 30 MPa, the force for pressing the amorphous alloy ribbons against each other is insufficient, and the density of the obtained joined body is not improved.

The shape of the amorphous alloy ribbon joined according to the present invention is not particularly limited. The electrical resistance between the thin ribbons to be joined is preferably 10 mΩ or more from the viewpoint of obtaining the required heat generation. When the electric resistance is extremely low, it is possible to employ a means for interposing a high resistance joining insert material such as ceramics or for providing a high resistance thin film on the surface of the ribbon. As for the material, as is clear from the examples described later, Fe: 40 to 90 atom%, C
It is preferable to contain o: 50 to 90 atomic% or Al: 80 to 90 atomic%. Although air may be used as the sintering atmosphere, an inert atmosphere, a vacuum atmosphere or the like is preferable in order to suppress the oxidation of the powder particle surface.

[0012]

【Example】

Example 1: Thickness 5 cut from various amorphous alloy ribbons
100 pieces of 0 μm and 10 mm square thin pieces were laminated inside a tool steel mold, set in a vacuum atmosphere, and joined under the conditions shown in Table 1. Conditions 1 to 8 are in accordance with the present invention, and Conditions 9 to 13 are examples in which one or more conditions are out of the range specified in the present invention. The following materials were used as the amorphous alloy material (unit: atomic%). Fe-based Fe ₉₀ Zr ₁₀ Fe ₇₅ Si ₁₀ B ₁₅ Fe ₆₅ Si ₂₅ B ₁₀ Fe ₆₂ Mo ₂₀ C ₁₈ Fe ₄₆ Cr ₁₆ Mo ₂₀ C ₁₈ Fe ₄₀ Ni ₄₀ P ₁₄ B ₆ Fe ₄₀ Ni ₃₈ Mo ₄ B ₁₈ Fe _73.5 Si _13.5 B ₉ Cu ₁ Nb ₃ Co system Co ₉₀ Zr ₁₀ Co ₇₅ Si ₁₅ B ₁₀ Co ₅₀ Cr ₃₀ C ₂₀ Co _70.5 Fe _4.5 Si ₁₀ B ₁₅ Co ₆₆ Fe ₄ Ni ₁ Si ₁₄ B ₁₅ Al system Al ₉₀ Y ₁₀ Al ₈₅ Ni ₅ Y ₁₀ Al ₈₄ Ni ₁₀ Ce ₄ Mg ₂ Al ₈₅ Zr ₅ Ni ₁₀ Ni System Ni ₉₀ Zr ₁₀ Ni ₇₅ Si ₈ B ₁₇ Ni ₆₄ Pd ₁₆ P ₂₀ Ni ₇₀ Mo ₂₀ C ₁₀ Cu System Cu ₆₀ Zr ₄₀ Cu ₅₀ Ti ₅₀ Mo type Mo ₇₅ Si ₅ B ₂₀ Mo ₈₀ P ₁₀ B ₁₀

[0013]

[Table 1]

Regarding the obtained bulk body, an amorphous state,
Delamination and relative density were investigated. As a result, condition 1
In the case of the bonded bodies of Nos. 5 and 8, the bulk structure obtained from any of the amorphous alloy ribbons maintains the amorphous structure without delamination and has a relative density. Is 9
It was 5% or more. The bulk body obtained under the conditions 6 and 7 is
Similarly, the amorphous structure was maintained without delamination, and the relative density was in the range of 90 to 95%. On the other hand, in the bulk body obtained under the conditions 9 to 13, the relative density did not reach 90%, or crystallization occurred. As is clear from this comparison, when joining the amorphous alloy ribbons under the conditions satisfying the range specified in the present invention, a high-density bulk body can be obtained while maintaining the relative density of 90% or more. I knew that.

Example 2 F of 20 mm square with a thickness of 25 μm
e ₇₅ Si ₁₀ B ₁₅ (atomic%), Co _72.5 Si _12.5 B ₁₅ (atomic%), and Al ₈₅ Ni ₅ Y ₁₀ (atomic%) 100 amorphous alloy ribbons were respectively supplied with high frequency current, A bulk body was obtained in which the ribbons were joined together. Bonding conditions are pressure 30
The influence of the junction temperature on the relative density was investigated by keeping 0 MPa, the frequency 5 kHz, and the discharge time constant for 15 minutes.
The joining temperature was adjusted by the amount of electricity input. When the relative density of the obtained bulk body was arranged by the temperature difference (= crystallization temperature-junction temperature), the relationship shown in FIG. 1 was established. For the evaluation in FIG. 1, the same criteria as in Example 1 were adopted. When the decrease in the joining temperature from the crystallization temperature was higher than 150 ° C, the relative density of the joined body was lowered, and conversely, when it was lower than 10 ° C, crystallization was detected. Therefore, the proper range of the bonding temperature is 10 in terms of temperature difference (= crystallization temperature-bonding temperature).
It can be seen that the temperature is in the range of up to 150 ° C. Further, in order to obtain a bonded body having a higher relative density, a temperature difference of 100 ° C. or less is preferable.

Example 3 The same amorphous alloy ribbon as in Example 2 was electrically heated to a temperature lower by 50 ° C. than the crystallization temperature to obtain a bulk bonded body. Then, the relationship between the frequency of the supplied current and the relative density of the bonded body was investigated. It can be seen from FIG. 2 showing the investigation results that a high-density bulk-like bonded body can be obtained when the frequency is 100 Hz to 100 kHz.
Above all, when a current having a frequency of 1 to 100 kHz was supplied, a high quality bonded body having a relative density of 95% or more was obtained. In this example, the same criteria as in Example 1 were evaluated, and the other conditions were the same as in Example 2.

Example 4 A pressure of 500 MPa was applied to the same amorphous alloy ribbon as in Example 2, and a current having a frequency of 3 kHz was set to 0.5 so that the bonding temperature was 30 ° C. lower than the crystallization temperature.
It was supplied for -25 minutes to manufacture a bulk bonded body. And
The effect of current supply time on the relative density of the joint was investigated. As shown in FIG. 3 showing the investigation result, the proper range of the current supply time is 1 to 20 minutes, and it was found that the energization time of 3 to 20 minutes is preferable in order to obtain a higher density joined body. . In this example, the same criteria as in Example 1 were evaluated, and the other conditions were the same as in Example 2.

Example 5: The same amorphous alloy ribbon as in Example 2 was used so that the bonding temperature was 70 ° C. lower than the crystallization temperature.
A current having a frequency of 7 kHz was supplied for 10 minutes to manufacture a bulk-like bonded body. Then, the influence of the pressure applied to the amorphous alloy ribbon on the relative density of the joined body was investigated. It can be seen from FIG. 4 showing the investigation result that the relative density of the obtained joined body is improved by applying a pressure of 30 MPa or more. Further, it is understood that it is preferable to press the amorphous alloy at 100 MPa or more in order to obtain a bonded body with higher density. In addition, in FIG. 4, the joined body was evaluated according to the same evaluation criteria as in Example 1.

Example 6: Each thickness is 25 to 75 μm
Using 150 sheets of Fe-based, Co-based, and Al-based amorphous alloy ribbons of 8 mm square with m, held at a pressure of 200 MPa with various additive elements and composition ranges, and a bonding temperature 120 ° C lower than the crystallization temperature. 1 frequency current of 800 hertz
It was supplied for 0 minutes to produce a bulk bonded body. The amorphous state and relative density of the obtained bulk body were investigated. As shown in Table 3 showing the investigation results, a high-density bulk body was manufactured while maintaining the amorphous structure in any composition range containing the main components. In Table 2, the same evaluation criteria as in Example 1 were adopted.

[0020]

[Table 2]

[0021]

As described above, according to the present invention, various amorphous alloys can be formed without causing a structural change such as crystallization by applying a high frequency current under the conditions specified with reference to the joining temperature. A thin body is joined in a short time to obtain a bulk body. The obtained bulk body maintains the original amorphous structure and has high density and high strength. As described above, according to the present invention, a bulk body exhibiting the original physical properties of an amorphous material can be manufactured with good productivity and at low cost. The obtained amorphous alloy bulk body is used in a wide range of fields such as parts requiring high strength, corrosion resistant materials, magnetic materials, and design materials.

[Brief description of drawings]

FIG. 1 is a graph showing the influence of the temperature difference between the crystallization temperature and the joining temperature on the relative density of the joined body when the amorphous alloy ribbon is joined to manufacture the bulk body.

FIG. 2 is a graph showing the influence of frequency on the relative density of a bonded body when a bulk body is manufactured by bonding amorphous alloy ribbons.

FIG. 3 is a graph showing the effect of current application time on the relative density of a bonded body when a bulk body is manufactured by bonding amorphous alloy ribbons.

FIG. 4 is a graph showing the influence of the applied pressure on the relative density of the bonded body when manufacturing the bulk body by bonding the amorphous alloy ribbons.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B23K 20/22 B23K 20/22

Claims (2)

[Claims] 1. An amorphous alloy ribbon which is heated at a frequency of 100 Hz to 100 kHz and heated to a temperature lower than the crystallization temperature by 10 to 150 ° C. by heating the amorphous alloy ribbon under a pressure of 30 MPa or more. For 1 to 20 minutes, a method for joining amorphous alloy ribbons. 2. Fe: 40-90 atomic%, Co: 50-
The joining method according to claim 1, wherein an amorphous alloy ribbon containing 90 atomic% or Al: 80 to 90 atomic% is used.