JP2008214704A - Amorphous metal / metal glass joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joined body which is small in ΔT(=Tx-Tg) (Tx: crystallization temperature, Tg: glass point) and in which a joined surface is not crystallized in an amorphous metal or metal glass. <P>SOLUTION: There is provided the amorphous metal joined body obtained by joining the amorphous metal having an irregular crystal structure by a thermal method or a method using plastic deformation. Particularly, the joined body has a nanocrystal precipitated in a joint portion. Also, the metal glass having an extensive supercooling liquid region and a distinct glass transition point is joined by the thermal method or the method using the plastic deformation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an amorphous metal produced at a rapid cooling rate or a metal glass joined body having a wide range of supercooled melt and a clear glass transition point. Composites containing nanocrystals deposited in the bonding part or joined bodies joined with crystalline metals, and large members with structure and functionality in which crystalline metals are arrayed and joined in the plane direction, layer direction or any part , Relating to complex members.

Since amorphous metal or metallic glass must be rapidly cooled at a large cooling rate of 10 ^6-8 K / s, it is difficult to create a large member, and large members and complex shapes cannot be created. There were major restrictions on the application.

  For the production of large-sized members and complex shapes with the same strength as the base metal, welding and solder / wax bonding widely used in conventional crystalline metal bonding can be considered, but amorphous metal or metallic glass is glass. Since the transition point is 300-900 ° C, which is generally lower than the melting point of crystalline metal, it is weak against heat and its structure is fragile, so it is crystallized by conventional welding and solder / wax bonding methods applied to conventional crystalline metals. Therefore, it is difficult to produce a part made of amorphous metal or metallic glass.

  In addition, there may be a method of bonding with an organic adhesive, but there are problems with uniform bonding between members and member strength, and it is expensive, and peeling and strength reduction occur when used at a high temperature of 100 degrees or more. Depending on the situation, there is a risk of fire, so the application is severely restricted.

In relation to the present invention, Non-Patent Document 1 discloses electron beam bonding of the most stabilized metallic glass Zr ₄₁ Ti ₁₄ Cu ₁₂ Ni ₁₀ Be ₂₃ , and Non-Patent Document 2 describes ultra-stabilized metallic glass Pd ₄ 0Ni ₄₀ P. An example of friction welding using superplasticity of ₂₀ is reported in Non-Patent Document 3, and a pulse current welding method of the most stabilized metallic glass Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ is reported.

  These are all the most stabilized metallic glasses, and ΔT (= Tx−Tg) (Tx: crystallization temperature, Tg: glass point) is large. Some metal glasses have a small ΔT depending on the composition, and some have ΔT = 0 like an amorphous metal. For a wide range of applications, an amorphous metal or a metal glass bonded body having a small ΔT is required. Furthermore, a joined body joined with a crystalline metal is also necessary.

  Patent Document 1 describes a method of joining metallic glass by frictional heat using a rotating probe at a temperature of Tg or more and Tx or less.

JP 2003-285170 A Electron beam bonding; Y. Kawamura and Y. Ohno, Mater. Trans., 42, (2001), 2476 Friction welding: Y. Kawamura and Y. Ohno, Scripta Materia, 45 (2001) 279. Pulse current junction: Y. Kawamura, Mater. Sci. & Eng. A, 375-377 (2004) 112.

  The present invention has been made in view of the above-described prior art, and is a composite containing nanocrystals deposited on the same kind or different kinds of amorphous metal or metal glass or bonded portion, or a joined body joined with a crystalline metal. Furthermore, it is an object of the present invention to produce a structural member and a functional member having a large and complicated shape by bonding a crystalline metal in a plane direction, a layer direction, and an arbitrary place.

  The present inventors have conducted intensive research based on a new idea and directly joined the base material using laser, electron beam heating, electrical resistance heating, ultrasonic heating, frictional heat, etc. The present invention has been completed by finding a condition that an amorphous metal or a metallic glass is bonded before being crystallized through a bonding material such as a material.

  In this case, in order to directly bond without causing crystallization, it is necessary to devise such as increasing the bonding speed to suppress an increase in temperature diffusion or using an electron beam source as a heat source in which crystallization hardly occurs. It has also been found that there is a limit to the composition of the joined body. Furthermore, the electric resistance heating method requires a short application time, an appropriate contact pressure, and the like in the current value control, ultrasonic heating, friction stir welding method, etc. depending on the electric resistance.

  In solder / wax bonding, metallic glass and amorphous metal other than oxidation-resistant Pd-based and Au-based metallic glass are covered with an oxide film, so that direct bonding is difficult. Therefore, it is necessary to remove this oxide film immediately before joining. In brazing using metallic glass as a brazing material, it is necessary to cool the brazing material and the base material at a critical cooling rate or higher from the joining temperature to the glass transition point in order to prevent the formation of a brittle crystal layer on the brazing material portion. .

  Further, the friction stir welding method is a method in which a tool is rotated at a high speed of 100 rpm or more, the object to be welded is softened by the frictional heat, and is joined in a solid state using plastic deformation. It is necessary to change the press-fitting depth and the rotational speed depending on the material hardness of the joined body. When bonding is performed while maintaining the strength of the base material, there is a problem of the life of the bonding tool, and it is necessary to bond at a glass transition point (Tg) or higher and a crystallization temperature (Tx) or lower.

  The electric resistance heating method is a bonding method in which a current of 10 A or more is passed for a short time and rapid heating is performed. It is necessary to change the applied current depending on the specific electrical resistance of the object to be joined.

  In the ultrasonic method, by pressing the other material that vibrates ultrasonically against one fixed material, the bonding inhibition layer of the sliding interface is destroyed to form interface adhesion, and further initial adhesion formation After that, there is a joining technique that promotes the destruction of the joint-inhibiting layer on the surface of the deformed portion and the enlargement of the adhesion area by ultrasonic-induced deformation of the material without using solder / wax material. Since the energy supplied to the bonding interface of the material is not thermal energy as in the friction stir method, the energy can be effectively concentrated in the vicinity of the bonding interface. As a result, less energy is required for bonding of unit areas, and bonding can be performed in a very short time. That is, the temperature rise in the vicinity of the joint can be kept low. In addition, since bonding is performed in a solid state, bonding with extremely high dimensional accuracy is possible.

  The present invention is based on amorphous metal or metallic glass or bonded to crystalline metal by finding the condition that amorphous metal or metallic glass is bonded before crystallization, or by forming a metastable crystalline phase. The present invention provides a structural member and a small functional member having a large and complex shape. That is, the present invention has solved the weak point of amorphous metal or metallic glass that it is difficult to produce a large member. Furthermore, it has become possible to process high value-added amorphous metal or metallic glass into a fine molded body.

  Various thermal bonding methods are required to be used in a multifaceted manner by a plurality of methods depending on the parts of small, large, and complicated members. For example, it is desirable to use a combination of laser or electron beam bonding for a relatively large size, ultrasonic bonding for a relatively small portion, and solder bonding or the like for a portion having a curvature. In addition, diffusion bonding or electric resistance heating may be suitable for bonding complex shapes or multilayer materials.

  For example, in laser, electron beam, ultrasonic bonding, and solder bonding, it is possible to completely automate the production of an amorphous metal or metal glass bonded body.

  Examples of amorphous metal or metal glass bonded bodies having various compositions according to the present invention will be described below using various bonding conditions.

  Table 1 shows raw material compositions and reaction conditions of various materials. The materials to which the present invention is applied are all amorphous metals or metallic glasses included in the above claims, and are not limited to the materials described in Table 1.

The following is a table showing the composition, glass point, and sample size of amorphous metal or metallic glass having various compositions.

  1 and 2 are joined using a semiconductor YAG laser (26 W, beam diameter 0.3 m) and an electron beam (acceleration voltage 60 kV, current 3-5 mA, vacuum degree 0.1 Pa) using two samples No. 1 in Table 1. It is the result of structural analysis of the joint with X-rays and a transmission electron microscope.

  The graph of FIG. 1 has shown the X-ray-diffraction result of the bead front and back, the horizontal axis of the graph shows the angle of ˜, and the vertical axis shows the signal intensity. The upper left figure (a) shows the results when the welding speed is 2 m / min., The upper right figure (b) shows the results when the welding speed is 2.5 m / min, and the lower left figure (c) shows the results when the welding speed is 3 m / min. Is shown. The lower right figure (d) of FIG. 1 has shown the transmission-electron-microscope structural analysis result of bead front and back.

The graph of FIG. 2 is an X-ray analysis result after electron beam bonding, in which the horizontal axis indicates an angle of ˜ and the vertical axis indicates signal intensity. The graph results show the results in (a) a region without heat influence, (b) an oxide phase, and (c) a heat-affected region from the bottom. The image in Fig. 2 shows the results of transmission electron microscope analysis. From the left, (d) high-resolution image of the weld region, (e) diffraction image of the amorphous phase region, (f) bright-field image (g) hR- 14 Ni ₄ Ti ₃ single phase.

When the bonding speed of the semiconductor laser increased from 2 m / min to 3 m / min, the structure of the bonding portion changed from a crystalline phase to a substantially single amorphous phase. At low speed, nano metastable ridges hR14-Ni ₄ Ti ₃ appeared (Fig. 1 (d)). In order to prevent crystallization, a bonding speed of 4 m / min or more is required. Even if the nano quasicrystal is formed, the strength of the amorphous metal or metallic glass joined body is not lowered.

On the other hand, in the electron beam bonding, as is apparent from the X-ray analysis diagram ac) after electron beam bonding in FIG. 2 and the transmission electron microscope analysis result (dg), the bonding region was an amorphous phase. Similar results were obtained when the metal glass Cu ₆₀ Zr ₃₀ Ti ₁₀ of sample number 7 was used.

FIG. 3 is a schematic view of the current pressure welding method for metallic glass. By laminating the metal glass Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ of sample number 3 and rapidly heating the current, only the joint is preferentially heated. This welding method is one of the most suitable joining methods for metal glass and other rapid heating and cooling that are essential. The structure of the obtained bonded body cross section is shown in FIG. FIG. 4 is a cross-sectional structure of a sample in which four layers of Zr ₅₅ Cu ₃₀ Ni ₅ Al _{10 having} a thickness of 50 microns are joined by resistance welding. FIG. 5 is an X-ray diffraction result of the Zr-based metallic glass joint of this sample.

Four layers of Zr ₆₅ Ni ₁₀ Cu ₅ Al _7.5 Pd _12.5 with a sample number of 4 with a thickness of 50 microns are stacked in four layers and loaded with a pressure of 10 MPa, 450 ° C in the supercooled liquid region above the glass transition temperature of 399 ° C The current was rapidly heated and held for 5 seconds to perform bonding and rapidly cooled. In the cross-sectional structure, the four layers of metallic glass are joined so finely that no interlayer is detected, and no weld joint defect is observed. Moreover, there is no change in composition and it is amorphous.

FIG. 6 is an external view of a joined body joined by friction stir welding (FSW) using two samples of sample number 3 (Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ ). At this time, the rotation speed of the tool was 500 rpm, the moving speed (joining speed) was 50 mm / min, and the load was 550 kgf. The tool is SKD61 tool steel, shoulder diameter is 15mm, probe diameter is 5mm and left-handed. FIG. 7 shows the X-ray diffraction results at the joint of the Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ joint when the rotation speed of the tool is kept constant at 500 rpm and the moving speed is changed between 25 mm / min and 50 mm / min. Of the two graphs, the upper graph is the analysis result when the moving speed is 25 mm / min, and the lower graph is the analysis result when the moving speed is 50 mm / min. In the case of 25 mm / min, since the moving speed is too slow, the amount of heat input per unit distance is large, and the junction temperature has exceeded the crystallization temperature (Tx) of 768 K, so there is a peak indicating crystallization. On the other hand, when the speed is increased to 50 mm / min and the heat input per unit distance is decreased, the temperature becomes Tx or less, and the glass state can be maintained. When the bonding speed is further increased, the temperature gradually decreases, but at 125 mm / min or more, the temperature becomes the glass transition temperature (Tg) or less, and the plastic fluidity deteriorates, so that the shoulder floats from the sample, and the bonding is performed. It was impossible.

8 (indicated by triangles) rotational speed 500 rpm, welding speed 50 mm / min, when joined with a load 550 kgf, in a cross section perpendicular to the joining direction of the Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ joint, 0.5 mm from the surface, 1.0 Hardness distribution at positions of mm (indicated by squares) and 1.5 mm (indicated by circles). Thus, it is thought that it is much smaller than 900Hv at the time of crystallization, and has maintained the amorphous state substantially. The reason why it is slightly higher than 500 Hv of the base material is considered to be because finely crystallized particles are slightly dispersed. Similar results were obtained for sample number 9 (La ₅₅ Al ₂₀ Cu ₂₀ ).

  The destruction of the bonding inhibition layer in the ultrasonic bonding of amorphous alloy or metallic glass can be achieved relatively easily because of the low Young's modulus, which is one of the characteristics of the amorphous alloy or metallic glass. However, since amorphous alloys or metallic glasses are difficult to be plastically deformed at a process temperature lower than the glass transition point, in order to achieve adhesion across the entire joint surface, the local temperature during the joint process and the rough surface of the joint surface are difficult to achieve. Sophisticated control is essential.

  A typical configuration of the ultrasonic bonding apparatus is shown in FIG. The ultrasonic bonding apparatus includes a mechanism for generating / controlling a load, a mechanism for applying a load to the workpiece bonding portion, a mechanism for generating / controlling ultrasonic vibration, a mechanism for transmitting ultrasonic vibration to the workpiece bonding portion, It is equipped with at least a mechanism for grasping or fixing the workpiece, and it is equipped with a mechanism for controlling the temperature of the workpiece by heating and cooling and a positioning mechanism for accurately determining the joining position according to the material and dimensions of the workpiece. can do. Note that the ultrasonic bonding apparatus to which the present invention is applied is not limited to the embodiment shown in FIG. 9, but includes all apparatuses that satisfy the above-described configuration conditions.

Figure 10 shows the conditions of Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ thin ribbon ribbon contact surface of sample number 3 with ultrasonic frequency of 75 kHz, ultrasonic power of 7.25 W, ultrasonic application time of 600 ms, and no preheating. 2 is a cross-sectional optical microscopic structure of a bonded interface. FIG. 11 shows the X-ray diffraction pattern (a) of the bonding interface of metallic glass Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ ultrasonically bonded at room temperature and the X-ray diffraction pattern (b) of metallic glass Zr ₅₅ Cu ₃₀ Ni ₅ Al _10. ) Comparison.

  Since the plastic deformation of the metallic glass cannot be sufficiently induced without preheating, the joining occurs only partially. However, as shown in the micro-region X-ray diffraction pattern of FIG. 11, this bonding is achieved without any loss of the amorphous structure of the metallic glass as the base material. This means that ultrasonic bonding at room temperature is suitable as a temporary assembly technique for metallic glass. Since the temporary assembly is a process that determines the dimensional accuracy in joining, a technique for achieving the temporary assembly without affecting the characteristics of the metallic glass is important.

Sample No. 2 sample Ni _39.8 Nb _26.5 Zr _28.4 H _5.2 is also a metallic glass containing hydrogen, but it can be joined and expected for an electronic device. Two sample pieces having different compositions of sample number 8 (Fe ₇₀ Hf ₁₀ B ₂₀ ) and sample number 10 (Fe ₈₀ Nb ₁₀ B ₁₀ ) could be joined.

FIG. 12 shows a sample No. 5 (Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ ) in the table as a brazing material and a Cu test piece (φ6 mm, length 20 mm) is held at 923 K for 1 minute and then rapidly cooled at an average cooling rate of 30 K / sec. The temperature history when diffusion bonding is performed. By inserting a 1 mm thick quartz spacer into the joint, the metallic glass wax is joined with a thickness of about 1 mm. FIG. 13 is a micro X-ray diffraction pattern (spot diameter φ50 μm) of a joined body in which Cu is brazed with Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ . Among the three graphs, the results of the base material part, the metal glass wax part (400 μm from the center), and the metal glass wax part (center) are shown from the top. The metallic glass wax was joined to the base material in an amorphous state.

Figure 14 shows the use of Sn-3.0Ag-0.5Cu lead-free solder between two Pd-based metallic glass samples of sample number 5 (Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ ) at 250 ° C for 1 minute in a nitrogen atmosphere. It is the result of the optical micrograph of the sample cross section heated by. The metallic glass interface is bonded without crystallizing. Similar results were obtained for sample number 6 (Pd _42.5 Cu ₃₀ Ni _7.5 P ₂₀ ).

The results of the joined body are summarized in Table 2. Sample number 1 (Ni ₅₃ Nb ₂₀ Ti ₁₀ Zr ₈ Co ₆ Cu ₃ ), sample number 2 (Ni ₅₃ Nb ₂₀ Ti ₁₀ Zr ₈ Co ₆ Cu ₃ ), sample number 3 (Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ ) The joined part was completely amorphous at the joined part, and the tensile strength was equivalent to the base material strength.

The following is a table showing the results of various joined bodies.

  As described in detail in Example 1-6, the present invention makes it possible to produce structural and functional members that are small, large, and have complicated shapes.

X-ray analysis diagram (ac) and transmission electron microscope analysis result (d) of various parts of laser-bonded Ni ₅₃ Nb ₂₀ Ti ₁₀ Zr ₈ Co ₆ Cu ₃ metallic glass. X-ray analysis diagram (ac) and transmission electron microscope analysis result (dg) of Ni ₅₃ Nb ₂₀ Ti ₁₀ Zr ₈ Co ₆ Cu ₃ metallic glass bonded by electron beam Schematic diagram of current welding method for metallic glass Cross-sectional structure of a sample in which four layers of Zr ₅₅ Cu ₃₀ Ni ₅ Al _{10 with} a thickness of 50 microns are joined by resistance welding X-ray diffraction results of Zr-based metallic glass joints Appearance photograph of Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ joint with friction stir welding X-ray diffraction results of Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ joint with friction stir welding (tool rotation speed is 500 rpm) Cross-sectional hardness distribution of friction stir welded Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ joint (rotation speed 500rpm, welding speed 50mm / min, load 550kgf) Configuration example of typical ultrasonic bonding equipment Bonding interface structure of metallic glass Zr ₅₅ Cu ₃₀ Ni ₅ Al ₁₀ ultrasonically bonded at room temperature At room temperature in comparison ultrasonic bonding metal glass Zr ₅₅ Cu ₃₀ Ni ₅ X-ray diffraction pattern (a) of the bonding interface between Al ₁₀ and X-ray diffraction pattern of the metallic glass _{Zr 55 Cu 30 Ni 5 Al 10} (b). Temperature history when soldering Cu with metallic glass wax Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ Fine X-ray diffraction pattern (spot diameter φ50μm) of a joint obtained by brazing Cu with Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ 1, base metal part, 2, metal glass wax part (400μm from center), 3, metal glass wax part (center) Results of optical micrograph of sample cross section of metallic glass Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ joined by Sn-3.0Ag-0.5Cu lead-free solder

Claims (12)

  An amorphous metal joined body in which an amorphous metal having an irregular crystal structure is joined by a thermal method or a plastic deformation method.   A metallic glass joined body in which a metallic glass having a wide range of supercooled melt and a clear glass transition point is joined by a thermal method or a plastic deformation method among the amorphous metals described in claim 1.   An amorphous metal or metallic glass joined body comprising nanocrystals deposited at a joint portion where the amorphous metal or metallic glass according to claim 1 or 2 is joined by a thermal method.   A bonded body obtained by bonding an amorphous metal or metallic glass according to claim 1, 2 or 3, or a nanocrystal deposited at a bonded portion, to the crystalline metal.   The composition of the amorphous metal or metallic glass joined body according to claim 1, 2 or 3 is composed of at least two kinds in the plane direction, and is bonded to the amorphous metal or metallic glass joined body or crystalline metal. Joined body.   Amorphous metal or metallic glass joined body or crystalline metal, characterized in that the composition of the amorphous metal or metallic glass joined body according to claim 1, 2 or 3 is superposed in the layer direction and consists of at least two kinds. The joined body joined with.   The amorphous metal or metallic glass joined body according to any one of claims 1, 2, 3, and 4 is composed of a combination of any composition at any particular location, or A bonded body bonded to a crystalline metal.   Amorphous metal or metallic glass, characterized in that the joining portion of the amorphous metal or metallic glass joined body according to claim 1, 2, 3, 4, 5, 6, 7 is composed of an element of a constituent base material. Bonded body or bonded body bonded to crystalline metal.   Amorphous metal or metallic glass joint characterized in that the amorphous metal or metallic glass joined body described in claim 1, 2, 3, 4, 5, 6, or 7 is joined with a different metal such as solder or brazing material. Body or joined body joined with crystalline metal.   The amorphous metal or metallic glass joined body described in claims 1, 2, 3, 4, 5, 6, 7, and 8 has a strength equal to or higher than that of the base material. A bonded body bonded to the amorphous metal or metallic glass bonded body or crystalline metal described.   The amorphous metal or metallic glass joined body according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9, wherein the amorphous metal or metallic glass having different electromagnetic properties is surface-oriented or layer-oriented or arbitrary A bonded body bonded to an amorphous metal, a metallic glass bonded body, or a crystalline metal, characterized in that a member having an arbitrary composition is bonded at a specific portion of the above.   The amorphous metal or metallic glass joined body according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, wherein the amorphous metal or metallic glass has different mechanical, electromagnetic, and corrosion resistant properties, or other types. An amorphous metal, a metallic glass joined body, or a joined body joined to a crystalline metal, characterized in that a crystalline metal is joined to an arbitrary composition in a plane direction, a layer direction, or an arbitrary specific portion.