A method of welding an aluminum matrix composite and an aluminum matrix composite joint

Abstract

The application provides a welding method of an aluminum-based composite material and an aluminum-based composite material joint, and relates to the technical field of welding.The welding method comprises the following steps: plating a metal layer on a welding surface of an aluminum-based composite material to obtain a welding piece; wherein the aluminum-based composite material comprises an aluminum base and a ceramic reinforcing phase; the metal layer is used to form a eutectic phase with the aluminum base; the melting point of the eutectic phase is below 440 DEG C; two welding pieces are assembled to make the metal layers of the two pieces adhere to each other to obtain an assembled piece; under vacuum conditions, a preset pressure is applied to the assembled piece, and the assembled piece is heated to a welding temperature under the action of a pulse current, and is kept warm for a preset time, and is cooled to room temperature to obtain an aluminum-based composite material joint; wherein the direction of the pulse current is perpendicular to the welding surface of the aluminum-based composite material. By using the method, an aluminum-based composite material joint with high strength and low deformation rate can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding, in particular to a welding method of aluminum matrix composite material and aluminum matrix composite material joint. BACKGROUND

[0002] Aluminum matrix composite material has high specific strength, high specific stiffness, strong wear resistance, good dimensional stability and other excellent properties, and is an ideal material for manufacturing heat dissipation micro-channel devices. The heat dissipation micro-channel device contains a large number of micro-channel structures with a width of millimeters or even microns. In order to avoid the blockage of liquid filler metal in these micro-channels, the heat pressure diffusion welding technology is currently mainly used for its preparation. The welding temperature of the traditional heat pressure diffusion welding method needs to reach more than 90% of the melting point of the base material itself, otherwise it will be difficult to drive the plastic deformation, atomic diffusion and interface healing at the weld due to insufficient heat field. In this process, the aluminum matrix composite material will not only undergo severe plastic deformation, resulting in the destruction of the micro-channel structure, but also the base material will be directly melted due to the fluctuation of the furnace temperature, resulting in a high deformation rate of the joint after welding. In addition, for some specific aluminum matrix composite materials, a large number of ceramic particles are contained as reinforcing phases, and the temperature required for atomic diffusion or interface reaction of these ceramic particles is much higher than the melting point of the base material itself. Therefore, at the welding temperature, the "metal / ceramic" interface and "ceramic / ceramic" interface at the joint cannot be combined through atomic diffusion or metallurgical reaction, resulting in poor bonding rate and strength of the diffusion welded joint, which is difficult to meet the actual application requirements. Therefore, for the heat pressure diffusion welding of aluminum matrix composite materials with ceramic as reinforcing phase, how to obtain an aluminum matrix composite material joint with high strength and low deformation rate has become a technical problem to be solved at present. SUMMARY

[0003] The problem solved by the present application is: for the heat pressure diffusion welding of aluminum matrix composite materials with ceramic as reinforcing phase, how to obtain an aluminum matrix composite material joint with high strength and low deformation rate.

[0004] To solve the above problems, the present application provides a welding method of aluminum matrix composite material, comprising:

[0005] Step S1, plating a metal layer on the welding surface of the aluminum matrix composite material to obtain a welding piece; wherein the aluminum matrix composite material comprises an aluminum matrix and a ceramic reinforcing phase, the metal layer is used to form a eutectic phase with the aluminum matrix, and the melting point of the eutectic phase is below 440℃;

[0006] Step S2, assembling two welding pieces to make the metal layers of the two pieces adhere to each other to obtain an assembled piece;

[0007] Step S3, under vacuum conditions, a preset pressure is applied to the assembly and the assembly is heated to a welding temperature under the action of a pulse current, and is kept for a preset time, and is cooled to room temperature, to obtain an aluminum matrix composite joint; wherein the direction of the pulse current is perpendicular to the welding surface of the aluminum matrix composite.

[0008] Optionally, in the step S1, the aluminum matrix is selected from at least one of aluminum, 8011 aluminum alloy, 6061 aluminum alloy, 6063 aluminum alloy, 5A06 aluminum alloy, 5052 aluminum alloy, 4004 aluminum alloy, 4032 aluminum alloy, 3003 aluminum alloy, 2024 aluminum alloy, 2A12 aluminum alloy and ZL101 aluminum alloy; and the ceramic reinforcing phase is selected from at least one of micron-sized silicon carbide particles, graphene nanosheets, micron-sized aluminum nitride particles and micron-sized diamond particles.

[0009] Optionally, in the step S1, the volume fraction of the ceramic reinforcing phase in the aluminum matrix composite is 20% to 70%.

[0010] Optionally, in the step S1, the preparation material of the metal layer is selected from at least one of Zn, Sn, Ge and Mg.

[0011] Optionally, in the step S1, the thickness of the metal layer is 0.05 μm to 0.2 μm.

[0012] Optionally, in the step S3, the duty cycle of the pulse current is 25% to 100%, the nominal peak current density is 3 A / mm 2 to 8 A / mm 2 , and the frequency is 50 Hz to 100 Hz.

[0013] Optionally, in the step S3, the welding temperature is 360℃ to 500℃.

[0014] Optionally, in the step S3, the preset time is 20 min to 60 min.

[0015] Optionally, in the step S3, the preset pressure is 3 MPa to 15 MPa.

[0016] The application also provides an aluminum matrix composite joint made by the welding method of the aluminum matrix composite as described above.

[0017] Compared with the related art, the present application first plates a metal layer on the welding surface of the aluminum matrix composite base material before carrying out hot pressure diffusion welding, the material for preparing the metal layer satisfies the condition that the metal layer is used to form a eutectic phase with the aluminum matrix, and the melting point of the eutectic phase is below 440 DEG C; since the melting point of the eutectic phase is relatively low, thus, at a relatively low welding temperature, the aluminum atoms at the welding interface of the two welding pieces can diffuse with the metal atoms in the metal layer and form eutectic liquid phases, and these eutectic liquid phases can flow through and completely cover the ceramic particles at the welding interface under the action of a certain pressure, thus converting the "ceramic / ceramic" weak connection interface and the "metal / ceramic" weak connection interface into a "metal / metal" strong connection interface, so that all the weak connection interfaces are eliminated by the generation of a small amount of liquid phase organization under a relatively low temperature condition, and the strength of the welding joint is greatly improved; and since the welding temperature in the welding process is relatively low, the possibility of plastic deformation of the aluminum matrix composite base material can also be reduced, so that the aluminum matrix composite joint with relatively high strength and relatively low deformation rate can be prepared. In addition, in the present application, during the welding process, the assembly is heated from the center to the edge by applying a pulse current perpendicular to the direction of the welding surface of the aluminum matrix composite, and under the skin effect of the pulse current, the welding interface (welding seam) of the welding piece has a relatively large current density, so that the welding seam can be rapidly heated for a short time, the efficiency of the welding process is greatly improved, and the plasma generated by the pulse current can activate the welding interface of the welding piece to reduce the welding temperature, so that the possibility of plastic deformation of the aluminum matrix composite base material can be further reduced, so that the prepared aluminum matrix composite joint has a lower deformation rate. In summary, for the hot pressure diffusion welding of the aluminum matrix composite with ceramic as the reinforcing phase, the method of the present application can obtain the aluminum matrix composite joint with relatively high strength and relatively low deformation rate. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic view of the hot pressure diffusion welding of the assembly in the embodiment of the present application.

[0019] Figure 2 It is a scanning electron microscope picture of the interface of the aluminum matrix composite joint prepared in Example 1.

[0020] BRIEF DESCRIPTION OF DRAWINGS:

[0021] 1, aluminum matrix composite; 2, metal layer; 3, upper graphite pressure head; 4, lower graphite pressure head; 5, upper electrode; 6, lower electrode. DETAILED DESCRIPTION

[0022] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a welding method for aluminum-based composite materials, comprising:

[0026] Step S1, plating a metal layer on the to-be-welded surface of the aluminum-based composite material to obtain a to-be-welded part; wherein the aluminum-based composite material comprises an aluminum matrix and a ceramic reinforcement phase, the metal layer is used to form a eutectic phase with the aluminum matrix, and the melting point of the eutectic phase is below 440° C.;

[0027] Step S2, assembling the two parts to be welded so that their metal layers are bonded together to obtain an assembly;

[0028] Step S3, under vacuum conditions, a preset pressure is applied to the assembly and the assembly is heated to a welding temperature under the action of a pulse current, and is kept for a preset time, and is cooled to room temperature to obtain an aluminum-based composite material joint; wherein the direction of the pulse current is perpendicular to the welding surface of the aluminum-based composite material.

[0029] Before the hot-pressing diffusion welding, a metal layer is plated on the welding surface of the aluminum-based composite material base metal, the material of the metal layer meets the condition that the metal layer is used to form a eutectic phase with the aluminum base, and the melting point of the eutectic phase is below 440℃; since the melting point of the eutectic phase is low, the aluminum atoms at the welding interface of the two welding parts can diffuse with the metal atoms in the metal layer and form a eutectic liquid phase at a lower welding temperature, and the eutectic liquid phase can quickly flow through and completely cover the ceramic particles at the welding interface under the action of a certain pressure, so that the “ceramic / ceramic” weak connection interface and the “metal / ceramic” weak connection interface are all converted into a “metal / metal” strong connection interface, thereby eliminating all weak connection interfaces through the generation of a small amount of liquid phase at a lower temperature, and greatly improving the strength of the welding joint; and since the welding temperature during welding is low, the possibility of plastic deformation of the aluminum-based composite material base metal can also be reduced, so that an aluminum-based composite material joint with high strength and low deformation rate can be prepared. In addition, in the welding process, a pulse current perpendicular to the direction of the welding surface of the aluminum-based composite material is applied to the assembly to heat the assembly from the center to the edge, and under the skin effect of the pulse current, the welding interface (welding seam) of the welding part has a large current density, so the welding seam can be quickly heated for a short time, greatly improving the efficiency of the welding process, and the plasma generated by the pulse current can activate the welding interface of the welding part to reduce the welding temperature, thereby further reducing the possibility of plastic deformation of the aluminum-based composite material base metal, so that the prepared aluminum-based composite material joint has a lower deformation rate. In summary, for the hot-pressing diffusion welding of aluminum-based composite materials with ceramic as the reinforcing phase, the method of the embodiment of the present application can obtain an aluminum-based composite material joint with high strength and low deformation rate.

[0030] In some embodiments of the present application, in the step S1, the aluminum base is selected from at least one of aluminum, 8011 aluminum alloy, 6061 aluminum alloy, 6063 aluminum alloy, 5A06 aluminum alloy, 5052 aluminum alloy, 4004 aluminum alloy, 4032 aluminum alloy, 3003 aluminum alloy, 2024 aluminum alloy, 2A12 aluminum alloy and ZL101 aluminum alloy; and the ceramic reinforcing phase is selected from at least one of micron-sized silicon carbide particles, graphene nanosheets, micron-sized aluminum nitride particles and micron-sized diamond particles.

[0031] In some embodiments of the present application, in the step S1, the volume fraction of the ceramic reinforcing phase in the aluminum matrix composite is 20% to 70%.

[0032] In some embodiments of the present application, in the step S1, the preparation material of the metal layer is selected from at least one of Zn, Sn, Ge and Mg.

[0033] In some embodiments of the present application, in the step S1, the thickness of the metal layer is 0.05 μm to 0.2 μm.

[0034] In some embodiments of the present application, in the step S1, the metal layer plated on the welding surface of the aluminum matrix composite is prepared by a magnetron sputtering method. In the magnetron sputtering process, the sputtering power is 80 W to 150 W, the sputtering time is 60 min to 150 min, the sputtering protective gas is Ar, the gas pressure is 1 Pa to 5 Pa, and the flow rate of the protective gas is 20 sccm.

[0035] In some embodiments of the present application, in the step S3, the duty cycle of the pulse current is 25% to 100%, the nominal peak current density is 3 A / mm 2 to 8 A / mm 2 , and the frequency is 50 Hz to 100 Hz.

[0036] In some embodiments of the present application, in the step S3, the welding temperature is 360℃ to 500℃, and the preset time is 20 min to 60 min.

[0037] In some embodiments of the present application, in the step S3, the preset pressure is 3 MPa to 15 MPa.

[0038] The present application also provides an aluminum matrix composite joint made by the welding method of the aluminum matrix composite as described above.

[0039] The present application will be further described below in conjunction with specific embodiments.

[0040] Embodiment 1

[0041] A1. After the surface to be welded of the aluminum-based composite material 1 is polished, cleaned and dried in sequence, a metal layer 2 is plated on the surface to be welded by magnetron sputtering to obtain a part to be welded; wherein, the aluminum-based composite material is composed of an aluminum matrix and a ceramic reinforcement phase, the aluminum matrix is ​​aluminum, the ceramic reinforcement phase is micron-sized silicon carbide particles, the volume fraction of the ceramic reinforcement phase in the aluminum-based composite material is 45%, the preparation material of the metal layer is Zn, the thickness of the metal layer is 0.1 μm, and the aluminum-based composite material is a cylinder with a diameter of 55 mm and a height of 10 mm; during the magnetron sputtering process, the sputtering power is 100 W, the sputtering time is 105 min, the sputtering shielding gas is Ar, the air pressure is 3 Pa, and the air flow rate of the shielding gas is 20 sccm.

[0042] A2. Assembling the two parts to be welded so that their metal layers 2 are in contact with each other to obtain an assembled part;

[0043] A3、 Figure 1 As shown, the assembly is placed in a pulse current-assisted diffusion welding device. After vacuuming, vertical pressure is applied to the assembly through the upper graphite press head 3 and the lower graphite press head 4. Under the action of the pulse current, the assembly is heated to the welding temperature, kept warm for a preset time, and cooled to room temperature to obtain an aluminum-based composite material joint; wherein, the direction of the pulse current is perpendicular to the surface to be welded of the aluminum-based composite material, and the pulse current is introduced by connecting the upper electrode 5 and the lower electrode 6 to an external pulse power supply. The duty cycle of the pulse current is 50%, and the nominal peak current density is 5A / mm 2 , the frequency is 75 Hz; the welding temperature is 450° C., the preset time is 40 min, and the preset pressure is 9 MPa.

[0044] It should be noted that Figure 1 In the figure, the upper F arrow represents the vertical downward pressure applied to the assembly, the lower F arrow represents the vertical upward pressure applied to the assembly, and the vertical downward center line arrow represents the direction of the pulse current.

[0045] Example 2

[0046] The difference from Example 1 is that the aluminum substrate is 8011 aluminum alloy, the ceramic reinforcement phase is micron-sized aluminum nitride particles, and the preparation material of the metal layer is Sn.

[0047] Comparative Example 1

[0048] The difference from example 1 is that step A1 is that the welding surface of the aluminum matrix composite 1 is sequentially polished, cleaned and dried to obtain a welding part; wherein the aluminum matrix composite is composed of an aluminum matrix and a ceramic reinforcing phase, the aluminum matrix is aluminum, the ceramic reinforcing phase is micron-sized silicon carbide particles, the volume fraction of the ceramic reinforcing phase in the aluminum matrix composite is 45%, and the aluminum matrix composite is a cylinder with a diameter of 55 mm and a height of 10 mm.

[0049] Step A2 is to assemble two welding parts so that the welding surfaces of the two parts are in contact to obtain an assembled part.

[0050] Comparative example 2

[0051] The difference from example 1 is that the preparation material of the metal layer is Al, and Al cannot form a eutectic phase with the aluminum matrix below 440℃.

[0052] Comparative example 3

[0053] The difference from example 1 is that step A3 is that the assembled part is placed in a diffusion welding device, vacuumized, and then vertical pressure is applied to the assembled part by the upper graphite pressure head 3 and the lower graphite pressure head 4, and the assembled part is heated to the welding temperature under the action of heat radiation, and then the temperature is kept for a preset time, and then cooled to room temperature to obtain an aluminum matrix composite joint; wherein the welding temperature is 450℃, the preset time is 40 min, and the preset pressure is 9 MPa.

[0054] Experimental example

[0055] The interface of the aluminum matrix composite joint prepared in example 1 is characterized by scanning electron microscopy, and the results are shown in Figure 2 From Figure 2 It can be seen that the aluminum matrix composite joint prepared in example 1 forms a better connection.

[0056] The deformation rate and shear strength of the aluminum matrix composite joints prepared in examples 1 to 2 and comparative examples 1 to 3 are detected, and the results are shown in table 1, from which it can be seen that compared with comparative examples 1 to 3, the deformation rate of the aluminum matrix composite joint prepared in examples 1 to 2 is lower and the shear strength is higher.

[0057] Table 1

[0058]

[0059] Although the present application is disclosed as above, the protection scope of the present application is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications will fall within the protection scope of the present application.

Claims

1. A welding method for aluminum-based composite materials, characterized in that: include: Step S1, plating a metal layer on the to-be-welded surface of the aluminum-based composite material by magnetron sputtering to obtain a to-be-welded part; wherein the aluminum-based composite material comprises an aluminum matrix and a ceramic reinforcement phase, the metal layer is used to form a eutectic phase with the aluminum matrix, and the melting point of the eutectic phase is below 440° C.; the preparation material of the metal layer is selected from at least one of Zn, Sn, Ge and Mg; and the thickness of the metal layer is 0.05 μm to 0.2 μm; Step S2, assembling the two parts to be welded so that their metal layers are bonded together to obtain an assembly; Step S3, under vacuum conditions, applying a preset pressure to the assembly and heating the assembly to a welding temperature under the action of a pulse current, keeping the temperature for a preset time, and cooling to room temperature to obtain an aluminum-based composite material joint; wherein, the direction of the pulse current is perpendicular to the surface to be welded of the aluminum-based composite material; at the welding temperature, the aluminum atoms at the welding interface of the two parts to be welded can diffuse with the metal atoms in the metal layer and form a eutectic liquid phase, and these eutectic liquid phases can flow through and cover the ceramic reinforcement phase at the welding interface under a certain pressure.

2. The welding method of aluminum-based composite material according to claim 1, characterized in that: In step S1, the aluminum matrix is ​​selected from at least one of aluminum, 8011 aluminum alloy, 6061 aluminum alloy, 6063 aluminum alloy, 5A06 aluminum alloy, 5052 aluminum alloy, 4004 aluminum alloy, 4032 aluminum alloy, 3003 aluminum alloy, 2024 aluminum alloy, 2A12 aluminum alloy and ZL101 aluminum alloy; and the ceramic reinforcement phase is selected from at least one of micron-sized silicon carbide particles, graphene nanosheets, micron-sized aluminum nitride particles and micron-sized diamond particles.

3. The welding method of aluminum-based composite material according to claim 1, characterized in that: In the step S1, the volume fraction of the ceramic reinforcement phase in the aluminum-based composite material is 20% to 70%.

4. The welding method of aluminum-based composite material according to claim 1, characterized in that: In step S3, the duty cycle of the pulse current is 25% to 100%, and the nominal peak current density is 3A / mm 2 Up to 8A / mm 2 , frequency is 50Hz to 100Hz.

5. The welding method of aluminum-based composite material according to claim 1, characterized in that: In step S3, the welding temperature is 360°C to 500°C.

6. The welding method of aluminum-based composite material according to claim 1, characterized in that: In step S3, the preset time is 20 minutes to 60 minutes.

7. The welding method of aluminum-based composite material according to claim 1, characterized in that: In step S3, the preset pressure is 3 MPa to 15 MPa.

8. An aluminum-based composite material joint, characterized in that: The aluminum-based composite material is manufactured by the welding method according to any one of claims 1 to 7.

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