CN112548303B - Aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method - Google Patents

Aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method Download PDF

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CN112548303B
CN112548303B CN202011373748.8A CN202011373748A CN112548303B CN 112548303 B CN112548303 B CN 112548303B CN 202011373748 A CN202011373748 A CN 202011373748A CN 112548303 B CN112548303 B CN 112548303B
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aluminum alloy
welding
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diffusion welding
vacuum
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CN112548303A (en
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王国峰
刘永康
李振伦
王珊
林海朋
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Harbin Institute of Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/02—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of a press ; Diffusion bonding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/22—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded
    • B23K20/233—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded without ferrous layer
    • B23K20/2333—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded without ferrous layer one layer being aluminium, magnesium or beryllium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/24—Preliminary treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/38—Electroplating: Baths therefor from solutions of copper
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/18—Electroplating using modulated, pulsed or reversing current
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/34—Pretreatment of metallic surfaces to be electroplated
    • C25D5/42—Pretreatment of metallic surfaces to be electroplated of light metals
    • C25D5/44—Aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/08—Non-ferrous metals or alloys
    • B23K2103/10—Aluminium or alloys thereof

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Abstract

The invention discloses an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, belonging to the technical field of diffusion welding, aiming at solving the problem that the prior aluminum alloy joint is limited by the space of a vacuum furnace chamber when in vacuum welding, the workpiece size of the aluminum alloy joint is limited, meanwhile, the test piece can be taken and put only after the cabin body is cooled to room temperature for a long time during vacuum welding, so that the production time of the procedure is greatly increased, and the problem of low production efficiency is caused. The copper film can effectively prevent the secondary oxidation of the surface of the aluminum alloy to be welded, avoid the influence of the oxide layer on the surface of the aluminum alloy on the performance of a welding joint, meanwhile, the diffusion coefficient of the surface to be welded is increased to achieve the activation effect, and the method is mainly used for welding the aluminum alloy joint under the non-vacuum condition in the rail transit and aerospace industries.

Description

Aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method
Technical Field
The invention belongs to the technical field of diffusion welding, and particularly relates to an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method.
Background
The aluminum alloy has the advantages of low density, high specific strength and specific stiffness, good heat resistance, excellent superplastic formability and the like, and is widely applied to components such as skins and partition plates of airplanes, low-temperature storage tanks of spacecrafts and the like. Therefore, the realization of the diffusion welding of the aluminum alloy is of great significance to the application of the aluminum alloy.
Aluminum as an active metal is highly susceptible to forming a dense and stable oxide film in air: (AL 2 O 3 ) The oxide film of aluminum is not decomposed when heated, so that the performance of the aluminum alloy welded joint is affected. Therefore, diffusion welding of aluminum alloy is often carried out in a vacuum environment, the requirements on vacuum diffusion welding equipment are very strict, and the vacuum diffusion welding area is often smaller than 1 x 1m due to the limitation of the space of a vacuum furnace chamber 2 (ii) a Thus limiting the use of diffusion welded articles of aluminum alloys in aerospace, nuclear industries, and the like. In addition, because the vacuum equipment has the characteristics that the cabin door needs to be opened at room temperature, the aluminum alloy diffusion welding is carried out in the vacuum equipment, and the test piece can be taken and placed only after the cabin body is cooled to the room temperature for a long time, so that the production time of the working procedure is greatly prolonged, and the production efficiency is low.
In view of the current situation of aluminum alloy diffusion welding, the invention creators provide an aluminum alloy non-vacuum diffusion welding method, which solves the important problem that aluminum alloy diffusion welding must be prepared in vacuum equipment, simply, conveniently and efficiently realizes aluminum alloy non-vacuum diffusion welding, greatly improves production efficiency, and obtains a welded aluminum alloy test piece with good performance.
Disclosure of Invention
The invention provides a method for activating non-vacuum diffusion welding of an aluminum alloy surface and subsequent heat treatment, aiming at solving the problems that the workpiece size of the aluminum alloy joint is limited by the space of a vacuum furnace chamber when the existing aluminum alloy joint is subjected to vacuum welding, and meanwhile, a test piece can be taken and placed only after being cooled to room temperature by a cabin body for a long time when the existing aluminum alloy joint is subjected to vacuum welding, so that the production time of the procedure is greatly increased, and the production efficiency is low;
an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method is realized by the following steps:
the method comprises the following steps: cleaning the surfaces to be welded of the aluminum alloys: mechanically grinding and polishing the surface of the aluminum alloy, and placing the aluminum alloy in an acetone solution to remove surface oil stains;
step two: removing the oxide film on the surface of the aluminum alloy: sequentially using an alkali solution and an acid solution to clean the aluminum alloy and removing an oxide film on the surface to be welded on the surface;
step three: carrying out electrodeposition of a copper film on the surface to be welded of the aluminum alloy;
step four: carrying out non-vacuum diffusion welding on an aluminum alloy joint sample;
step five: carrying out aging heat treatment on the welded aluminum alloy sample;
further, in the first step, sand paper with the mesh number from low to high is sequentially selected to mechanically polish and polish the surface of the aluminum alloy to be welded, and then the aluminum alloy and the dissimilar metal are placed in an acetone solution for ultrasonic cleaning to remove oil stains on the surfaces of the aluminum alloy and the dissimilar metal;
further, in the second step, the alkali solution is a sodium hydroxide solution, and the acid solution is a nitric acid solution;
further, in the second step, the concentration of the sodium hydroxide solution is 15 wt.%, and the concentration of the nitric acid solution is 10 vol.%; (ii) a
Further, in the third step, the solution using copper sulfate as main salt is used for the copper film to be electrodeposited on the surface of the aluminum alloy to be welded, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9;
further, in the third step, the thickness of the plated film of the middle layer is adjusted by controlling the electrodeposition time, the thickness of the plated film is 10 microns, and the size of the crystal grain is 30-50 nm;
further, the fourth step includes the steps of:
step four, firstly: firstly, preheating a non-vacuum diffusion welding furnace;
step four and step two: after the temperature in the non-vacuum diffusion welding furnace reaches the preheating temperature, stacking the aluminum alloy patterns with the copper films deposited on the surfaces as components to be welded, placing the components in the diffusion welding furnace into the non-vacuum diffusion welding furnace, simultaneously heating to the target temperature and applying pressure, and performing diffusion welding in an air environment;
step four and step three: after the welding of the components is finished, heat preservation, pressure maintaining and shaping are carried out in a furnace:
step four: after heat preservation, pressure maintaining and shaping, gradually reducing the temperature in the furnace to a preheating temperature, taking out the workpiece subjected to heat preservation, pressure maintaining and shaping from the non-vacuum diffusion welding furnace, and immediately putting the next group of components to be welded into the diffusion welding furnace;
step four and five: repeating the steps, and welding the multiple groups of components to be welded one by one until the welding process of all the components to be welded is completed;
further, the preheating temperature of the non-vacuum diffusion welding furnace in the first step is 400 degrees;
furthermore, the welding process parameters in the fourth step and the second step are that the temperature is raised to 450-550 ℃, and the applied welding pressure is 5-10 MPa;
further, the heat preservation time in the fourth step and the third step is 60-150 min;
further, the aluminum alloy pattern after the fifth welding is subjected to aging heat treatment in an air environment, and the process parameters are heat preservation for 10 hours, 24 hours or 48 hours under the condition that the heat preservation temperature is 160 ℃.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention provides an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, which prevents the surface of an aluminum alloy to be welded from contacting with air by electrodepositing a nano copper film on the surface of the aluminum alloy to be welded, prevents the formation of oxides, improves the interface diffusion rate, realizes the diffusion welding of the aluminum alloy and dissimilar metals in an air environment, namely in a non-vacuum diffusion welding furnace, and simplifies the equipment requirements.
2. The invention provides an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, which can pick and place a welding test piece when the temperature of a furnace chamber is 400 ℃, shorten the diffusion welding period, improve the production efficiency, reduce the production cost, perform aging strengthening treatment on the welded test piece, and improve the comprehensive mechanical property of a welding joint.
3. The invention provides an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, which adopts a non-vacuum diffusion welding platform with an ultra-large working area of 3 x 2m 2 Far exceeding the diffusion plateau area in the vacuum chamber (1 x 0.8 m) 2 ) Can realize the oversized aluminum alloy and dissimilar metalAnd (3) preparing a plate non-vacuum diffusion welding workpiece.
Drawings
FIG. 1 is a schematic view of a non-vacuum diffusion welding process of the aluminum alloy of the present invention;
FIG. 2 is a diagram of the morphology of the aluminum alloy electrodeposited nano-copper film of the present invention;
FIG. 3 is a schematic cross-sectional view of an assembly to be welded of an aluminum alloy sheet of the present invention;
FIG. 4 is a graphical representation of a post-weld joint of the aluminum alloy design of the present invention (a-e correspond to examples one-five, respectively).
Detailed Description
The first embodiment is as follows: the present embodiment is described with reference to fig. 1 to 4, and provides an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, which is realized by the following steps:
the method comprises the following steps: cleaning the surfaces to be welded of each aluminum alloy: mechanically grinding and polishing the surface of the aluminum alloy, and placing the aluminum alloy in an acetone solution to remove surface oil stains;
step two: removing the oxide film on the surface of the aluminum alloy: sequentially using an alkali solution and an acid solution to clean the aluminum alloy to remove an oxide film on the surface to be welded;
step three: carrying out electrodeposition of a copper film on the surface to be welded of the aluminum alloy;
step four: carrying out non-vacuum diffusion welding on an aluminum alloy joint sample;
step five: and carrying out aging heat treatment on the welded aluminum alloy sample.
The invention relates to an aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method, which changes the existing welding mode of aluminum alloy, prevents the surface of the aluminum alloy to be welded from contacting with air by electrodepositing a nano copper film on the surface of the aluminum alloy to be welded, prevents the formation of oxides, improves the interface diffusion rate, realizes the diffusion welding of the aluminum alloy in the air environment, namely in a non-vacuum diffusion welding furnace, and can simplify the equipment requirement, shorten the diffusion welding period, improve the production efficiency, reduce the production cost, increase the working space and meet the requirement of welding larger-size aluminum alloy joint workpieces.
The second embodiment is as follows: the present embodiment is described with reference to fig. 1 to 4, and the present embodiment further defines the first step of the first embodiment, in which sandpaper with a mesh size from low to high is sequentially selected to perform mechanical grinding and polishing on the surface of the aluminum alloy to be welded, and then the surface is placed in an acetone solution to perform ultrasonic cleaning, so as to remove oil stains on the surfaces of the aluminum alloy and the dissimilar metal. Other components and connection modes are the same as those of the first embodiment.
In the embodiment, the selection type of the abrasive paper is 400-1500 meshes, three types of abrasive paper are generally selected from coarse to fine for mechanical grinding and polishing, the mesh number of the abrasive paper used during grinding and polishing is gradually increased, so that the integrity of cleaning the surfaces of the aluminum alloy and the dissimilar metal is ensured, and better finish is ensured.
The third concrete implementation mode: this embodiment will be described with reference to fig. 1 to 4, and further limits the second step described in the second embodiment, in which the alkali solution is a sodium hydroxide solution and the acid solution is a nitric acid solution. The other components and the connection mode are the same as those of the second embodiment.
The fourth concrete implementation mode: this embodiment will be described with reference to fig. 1 to 4, and is further limited to the second step described in the third embodiment, in which the concentration of the sodium hydroxide solution is 15 wt.% and the concentration of the nitric acid solution is 10 vol.%. Other components and connection modes are the same as those of the third embodiment.
So set up, wash the effect that mainly reaches secondary degreasing and tentatively remove the oxide film with alkaline solution earlier, reuse acid solution washs and is to further remove the oxide film, and the aluminium alloy surface atom that activates simultaneously improves the diffusion coefficient.
The fifth concrete implementation mode: the present embodiment will be described with reference to FIGS. 1 to 4, and the present embodiment is further limited to the third step of the fourth embodiment, in which the electrodeposition of a copper film on the surface of an aluminum alloy to be welded is performed using sulfurThe process conditions of the solution with acid copper as main salt are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. The other components and the connection mode are the same as those of the fourth embodiment.
By the arrangement, the copper film with the grain size of nano grade is deposited on the surface to be welded of the aluminum alloy by the electro-deposition method, so that the surface to be welded can be activated to increase the atomic diffusion rate, and the aluminum alloy can be prevented from forming a compact oxidation film in the diffusion welding process and being secondarily oxidized.
The sixth specific implementation mode: the third step of the fifth embodiment is further defined by referring to fig. 1 to 4, and in the third step, the thickness of the middle layer coating is adjusted by controlling the electrodeposition time, the thickness of the coating is 10 μm, and the grain size is 30-50 nm. The other components and the connection mode are the same as the fifth embodiment mode.
In the embodiment, the thickness of the deposited copper film is not easy to be too large, the copper film has the function of activating the surface to be welded to increase the atomic diffusion rate, and simultaneously, the phenomenon that a compact oxide film is formed in the diffusion welding process of the aluminum alloy and is secondarily oxidized is prevented, if the thickness of the deposited copper film is large, the atomic diffusion distance is increased, and the significance of activating the surface to be welded to increase the diffusion rate is lost.
The seventh concrete implementation mode: the present embodiment will be described with reference to fig. 1 to 4, and the present embodiment further defines step four described in the sixth embodiment, and in the present embodiment, the step four includes the following steps:
step four, firstly: firstly, preheating a non-vacuum diffusion welding furnace;
step four and step two: after the temperature in the non-vacuum diffusion welding furnace reaches the preheating temperature, stacking the aluminum alloy patterns with the copper films deposited on the surfaces as components to be welded, placing the components in the diffusion welding furnace into the non-vacuum diffusion welding furnace, simultaneously heating to the target temperature and applying pressure, and performing diffusion welding in an air environment;
step four and step three: after the welding of the components is finished, heat preservation, pressure maintaining and shaping are carried out in a furnace:
step four: after heat preservation, pressure maintaining and shaping, gradually reducing the temperature in the furnace to a preheating temperature, taking out the workpiece subjected to heat preservation, pressure maintaining and shaping from the non-vacuum diffusion welding furnace, and immediately putting the next group of components to be welded into the diffusion welding furnace;
step four and five: and repeating the steps, and welding the multiple groups of assemblies to be welded one by one until the welding process of all the assemblies to be welded is completed. Other components and connection modes are the same as those of the sixth embodiment.
In the embodiment, the aluminum alloy is subjected to non-vacuum diffusion welding, and in order to improve the production efficiency, the component to be welded can be placed into a non-vacuum diffusion welding furnace at 400 ℃, heated to a target temperature and applied with pressure, and diffusion welding is performed in an air environment. After the heat preservation process is finished, when the temperature of the equipment is reduced to 400 ℃, the welded aluminum alloy test piece can be taken out, and the next group of components to be welded is immediately placed into a diffusion welding furnace. By taking and placing the welding test piece in a circulating manner, the non-vacuum diffusion welding of the aluminum alloy is efficiently realized, and the welded test piece with excellent performance is obtained.
The specific implementation mode is eight: the present embodiment will be described with reference to fig. 1 to 4, and the present embodiment further defines the fourth step of the seventh embodiment, and in the present embodiment, the preheating temperature of the non-vacuum diffusion welding furnace in the fourth step is 400 °. The other components and the connection mode are the same as those of the seventh embodiment mode.
The specific implementation method nine: the present embodiment is described with reference to fig. 1 to 4, and the present embodiment further defines the step four two of the specific embodiment, in which the welding process parameter in the step four two is to raise the temperature to 480 to 550 ℃, and the applied welding pressure is 5 to 10 MPa. The other components and the connection mode are the same as those of the eighth embodiment.
The detailed implementation mode is ten: this embodiment will be described with reference to fig. 1 to 4, and further defines the step four and three described in the ninth embodiment, and in this embodiment, the heat retention time in the step four and three is 90 min. The other components and the connection mode are the same as those of the ninth embodiment.
The concrete implementation mode eleven: the present embodiment is described with reference to fig. 1 to 4, and is further limited to the fifth step described in the tenth embodiment, in the present embodiment, the aluminum alloy pattern after being welded in the fifth step is subjected to aging heat treatment in an air environment, and the process parameters are heat preservation for 10h, 24h or 48h under the condition that the heat preservation temperature is 160 ℃. Other components and connection modes are the same as those of the embodiment.
So set up, can further improve the comprehensive mechanical properties who connects, especially improve the intensity that the aluminum alloy connects.
Examples
The invention selects any aluminum alloy plates with different grades such as 5A90, 2B06, 7B04, 2195 or 7050 and the like as diffusion welding materials, and carries out non-vacuum diffusion welding after a layer of copper film is electrodeposited on the surface to be welded, and the schematic diagram of the welding process is shown in figure 1. The size of a single-layer aluminum alloy plate to-be-welded piece is 150mm x 1.5mm, a copper film is electrodeposited on the to-be-welded surface of the single-layer aluminum alloy plate, the thickness of the copper film is micron-sized, the size of crystal grains is nanometer-sized, the surface state of the electrodeposited copper film on the to-be-welded surface is shown in fig. 2, a schematic cross-sectional view of an assembly to be welded formed by stacking aluminum alloy plates is shown in fig. 3 (a is a schematic view of stacking aluminum alloy plates corresponding to first to fourth examples when two aluminum alloy plates are welded, b is a schematic view of stacking aluminum alloy plates corresponding to fifth example when three aluminum alloy plates are welded), and a topographic view of an aluminum alloy type non-vacuum diffusion welded joint is shown in fig. 4.
The first embodiment is as follows:
firstly, using 400-mesh, 800-mesh and 1500-mesh sandpaper to sequentially and mechanically polish the to-be-welded surface of a 5A90 aluminum alloy plate and perform polishing treatment, and then placing the to-be-welded surface in an acetone solution to perform ultrasonic cleaning for 30min to remove oil stains on the surface of the aluminum alloy.
And cleaning the surface to be welded of the treated 5A90 aluminum alloy plate by using a 15 wt.% sodium hydroxide solution and a 10 vol.% nitric acid solution in sequence for removing an oxide film on the surface of the 5A90 aluminum alloy plate, wherein the cleaning time is 20min respectively, and then taking out the aluminum alloy plate, cleaning the residual nitric acid solution by using alcohol, and quickly transferring the aluminum alloy plate into an acetone solution for storage.
The electro-deposition copper film uses solution which takes copper sulfate as main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. Taking two 5A90 aluminum alloy plates out of an acetone solution, quickly transferring the two 5A90 aluminum alloy plates into a deposition solution for surface electro-deposition copper plating, wherein a copper film on a surface to be welded is compact and smooth, the thickness of a single-layer copper film is 10 mu m, the size of a crystal grain is 30-50nm, the copper film can prevent the surface to be welded of the aluminum alloy from contacting with oxygen, the aluminum alloy is prevented from being secondarily oxidized, a nanoscale copper crystal grain can activate the surface to be welded to increase the diffusion rate among atoms, two 5A90 aluminum alloy plates are stacked, and the surfaces to be welded are oppositely placed to form a component to be welded.
The method is to stack 5A90 aluminum alloy patterns with copper films electrodeposited on the surfaces as components to be welded, put the components in a diffusion welding furnace, and perform diffusion welding in an air environment to obtain a welding test piece. Welding technological parameters are as follows: the temperature is 500 ℃, the heat preservation time is 90min, the welding pressure is 5MPa, in order to improve the production efficiency, when the furnace temperature is 400 ℃, the components to be welded are placed into a welding furnace, after the temperature is raised to the target temperature, diffusion welding is carried out, and when the furnace temperature is cooled to 400 ℃, the 5A90 aluminum alloy welding test piece is taken out. The 5A90 aluminum alloy non-vacuum diffusion welding is realized through the steps, the welding rate of the welding joint reaches more than 85%, the thinning rate is 5.5%, and the shearing strength of the welding joint is 112.4 MPa.
And (3) performing aging heat treatment on the welded 5A90 aluminum alloy sample in an air environment, keeping the temperature for 10 hours at 160 ℃ as a technological parameter, and further improving the comprehensive mechanical property of the joint, wherein the strength of the joint is improved from 112.4MPa to 134.8 MPa.
The second embodiment:
firstly, sequentially mechanically grinding the to-be-welded surfaces of 2195 aluminum alloy plates by using 400-mesh, 800-mesh and 1500-mesh sand paper, polishing, and then placing the to-be-welded surfaces in an acetone solution for ultrasonic cleaning for 30min to remove oil stains on the surfaces of the aluminum alloys.
And cleaning the to-be-welded surface of the treated 2195 aluminum alloy plate by using 15 wt.% sodium hydroxide solution and 10 vol.% nitric acid solution in sequence for removing the oxide film on the surface of the 2195 aluminum alloy plate, wherein the cleaning time is 20min respectively, and then taking out the aluminum alloy plate, cleaning the residual nitric acid solution by using alcohol, and quickly transferring the aluminum alloy plate into acetone solution for storage.
The electro-deposition copper film uses solution which takes copper sulfate as main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. Taking two 2195 aluminum alloy plates out of the acetone solution, quickly transferring the two 2195 aluminum alloy plates into a deposition solution for surface electro-deposition copper plating, wherein a copper film on the surface to be welded is compact and smooth, the thickness of a single-layer coating film is 10 mu m, the size of a crystal grain is 30-50nm, the copper film can prevent the surface to be welded of the aluminum alloy from contacting with oxygen, the aluminum alloy is prevented from being secondarily oxidized, the nanoscale copper crystal grain can activate the surface to be welded to increase the diffusion rate among atoms, two 2195 aluminum alloy plates are stacked, and the surfaces to be welded are oppositely placed to form a component to be welded.
The method comprises the steps of stacking 2195 aluminum alloy plates with copper films electrodeposited on the surfaces as components to be welded, placing the components in a diffusion welding furnace, and performing diffusion welding in an air environment to obtain a welding test piece. Welding technological parameters are as follows: the temperature is 520 ℃, the heat preservation time is 90min, the welding pressure is 5MPa, in order to improve the production efficiency, when the furnace temperature is 400 ℃, the components to be welded are placed into the welding furnace, after the temperature is raised to the target temperature, diffusion welding is carried out, and when the furnace temperature is cooled to 400 ℃, the 2195 aluminum alloy welding test pieces are taken out. The non-vacuum diffusion welding of the 2195 aluminum alloy is realized through the steps, the welding rate of the welding joint reaches over 95 percent, the thinning rate is 6.4 percent, and the strength of the welding joint is 177.5 MPa.
Aging heat treatment is carried out on the welded 2195 aluminum alloy sample in an air environment, the process parameter is 160 ℃, the heat preservation is carried out for 48 hours, the comprehensive mechanical property of the joint can be further improved, and the shear strength of the joint is improved from 177.5MPa to 249.4 MPa.
Example three:
firstly, the surfaces to be welded of 2B06 and 7B04 aluminum alloy plates are mechanically ground and polished by 400-mesh, 800-mesh and 1500-mesh sandpaper in sequence, and then the aluminum alloy plates are placed in an acetone solution for ultrasonic cleaning for 30min to remove oil stains on the surfaces of the aluminum alloys.
And cleaning the surfaces to be welded of the treated 2B06 and 7B04 aluminum alloy plates by using a 15 wt.% sodium hydroxide solution and a 10 vol.% nitric acid solution in sequence, removing oxide films on the surfaces to be welded of the 2B06 and 7B04 aluminum alloy plates, wherein the cleaning time is 20min respectively, taking out the aluminum alloy plates, cleaning the residual nitric acid solution by using alcohol, and quickly transferring the aluminum alloy plates into an acetone solution for storage.
The electro-deposition copper film uses solution which takes copper sulfate as main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. Taking out the 2B06 and 7B04 aluminum alloy plates from an acetone solution, quickly transferring the aluminum alloy plates into a deposition solution for surface electro-deposition copper plating, wherein a copper film on the surface to be welded is compact and smooth, the thickness of a single-layer coating film is 10 mu m, the size of a crystal grain is 30-50nm, the copper film can prevent the surface to be welded of the aluminum alloy from contacting with oxygen, the aluminum alloy is prevented from being secondarily oxidized, the nanoscale copper crystal grain can activate the surface to be welded to increase the diffusion rate among atoms, the 2B06 and 7B04 aluminum alloy plates are stacked, and the surfaces to be welded are oppositely placed to form a component to be welded.
The aluminum alloy was subjected to non-vacuum diffusion welding by stacking 2B06 and 7B04 aluminum alloy patterns with an electrodeposited copper film on the surface as a member to be welded in a diffusion welding furnace and performing diffusion welding in an air atmosphere to obtain a welded specimen. Welding technological parameters are as follows: the temperature is 550 ℃, the heat preservation time is 90min, the welding pressure is 5MPa, in order to improve the production efficiency, when the furnace temperature is 400 ℃, the components to be welded are placed in a welding furnace, after the temperature is raised to the target temperature, diffusion welding is carried out, and when the furnace temperature is cooled to 400 ℃, the 2B06 and 7B04 aluminum alloy welding test pieces are taken out. The non-vacuum diffusion welding of the 2B06 and 7B04 aluminum alloys is realized through the steps, the welding rate of the welding joint reaches over 95 percent, the thinning rate is 7.2 percent, and the strength of the welding joint is 162.4 MPa.
And (3) carrying out aging heat treatment on the welded 2B06 and 7B04 aluminum alloy test pieces in an air environment, keeping the temperature for 24 hours at 160 ℃ as a technological parameter, further improving the comprehensive mechanical property of the joint, and improving the strength of the joint from 162.4MPa to 183.1 MPa.
Example four:
firstly, the surfaces to be welded of 5A90 and 7050 aluminum alloy plates are mechanically ground and polished by 400-mesh, 800-mesh and 1500-mesh sandpaper in sequence, and then the surfaces are placed in an acetone solution for ultrasonic cleaning for 30min to remove oil stains on the surfaces of the aluminum alloys.
And cleaning the surfaces to be welded of the treated 5A90 and 7050 aluminum alloy plates by using a 15 wt.% sodium hydroxide solution and a 10 vol.% nitric acid solution in sequence for removing oxide films on the surfaces to be welded of the 5A90 and 7050 aluminum alloy plates, wherein the cleaning time is 20min respectively, and then taking out the aluminum alloy plates, cleaning the residual nitric acid solution by using alcohol, and quickly transferring the aluminum alloy plates into an acetone solution for storage.
The electro-deposition copper film uses solution which takes copper sulfate as main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. Taking two 5A90 aluminum alloy plates out of an acetone solution, quickly transferring the two plates into a deposition solution for surface electro-deposition copper plating, wherein a copper film on a surface to be welded is compact and smooth, the thickness of a single-layer coating film is 10 mu m, the size of a crystal grain is 30-50nm, the copper film can prevent the surface to be welded of the aluminum alloy from contacting with oxygen, the aluminum alloy is prevented from being secondarily oxidized, a nano-scale copper crystal grain can activate the surface to be welded to increase the diffusion rate among atoms, the 5A90 aluminum alloy plates and the 7050 aluminum alloy plates are stacked, and the surfaces to be welded are oppositely placed to form a component to be welded.
The aluminum alloy is subjected to non-vacuum diffusion welding by stacking 5A90 aluminum alloy patterns with copper films electrodeposited on the surfaces and 7050 aluminum alloy patterns as components to be welded, placing the components in a diffusion welding furnace, and performing diffusion welding in an air environment to obtain a welding test piece. Welding technological parameters are as follows: the temperature is 540 ℃, the heat preservation time is 60min, the welding pressure is 5MPa, in order to improve the production efficiency, when the furnace temperature is 400 ℃, the components to be welded are placed into a welding furnace, after the temperature is raised to the target temperature, diffusion welding is carried out, and when the furnace temperature is cooled to 400 ℃, the 5A90 and 7050 aluminum alloy welding test pieces are taken out. The non-vacuum diffusion welding of the 5A90 and 7050 aluminum alloys is realized through the steps, the welding rate of the welding joint reaches over 95 percent, the thinning rate is 4.5 percent, and the strength of the welding joint is 146.7 MPa.
And (3) carrying out aging heat treatment on the welded 5A90 and 7050 aluminum alloy samples in an air environment, keeping the temperature for 10 hours at 160 ℃ as a technological parameter, further improving the comprehensive mechanical property of the joint, and improving the strength of the joint from 146.7MPa to 165.9 MPa.
EXAMPLE five
Firstly, the surfaces to be welded of 7B04, 2B06 and 7050 aluminum alloy plates are mechanically ground and polished by 400-mesh, 800-mesh and 1500-mesh sandpaper in sequence, and then the aluminum alloy plates are placed in an acetone solution for ultrasonic cleaning for 30min to remove oil stains on the surfaces of the aluminum alloys.
And cleaning the surfaces to be welded of the treated 7B04, 2B06 and 7050 aluminum alloy plates by using a sodium hydroxide solution with the concentration of 10 wt.% and a nitric acid solution with the concentration of 15 vol.% to remove oxide films on the surfaces to be welded of the 7B04, 2B06 and 7050 aluminum alloy plates, wherein the cleaning time is 20min respectively, and then taking out the aluminum alloy plates, cleaning the residual nitric acid solution by using alcohol, and quickly transferring the aluminum alloy plates into an acetone solution for storage.
The electro-deposition copper film uses solution which takes copper sulfate as main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the PH value is 8-9. And taking out the 7B04, 2B06 and 7050 aluminum alloy plates from the acetone solution, quickly transferring the aluminum alloy plates into a deposition solution for surface electro-deposition copper plating, wherein the copper film on the surface to be welded is compact and smooth, the thickness of a single-layer coating film is 10 mu m, and the grain size is 30-50 nm. The copper film can prevent the surface to be welded of the aluminum alloy from contacting with oxygen, so that the aluminum alloy is prevented from being secondarily oxidized, and the nano-scale copper crystal grains can activate the surface to be welded and increase the diffusion rate among atoms. Wherein the 2B06 aluminum alloy plate is located between the 7B04 and 7050 aluminum alloy plates, so double-sided electrodeposition of copper films is required. The 7B04, 2B06 and 7050 aluminum alloy plates were stacked, and the surfaces to be welded were placed opposite to each other to form a unit to be welded.
The method comprises the steps of stacking 7B04, 2B06 and 7050 aluminum alloy plates with copper films deposited on the surfaces to form a component to be welded, placing the component in a diffusion welding furnace, and performing diffusion welding in an air environment to obtain a welding test piece. Welding technological parameters are as follows: the temperature is 530 ℃, the heat preservation time is 150min, the welding pressure is 5MPa, in order to improve the production efficiency, when the furnace temperature is 400 ℃, the components to be welded are placed into the welding furnace, after the temperature is raised to the target temperature, diffusion welding is carried out, and when the furnace temperature is cooled to 400 ℃, the 7B04, 2B06 and 7050 aluminum alloy welding test pieces are taken out. The non-vacuum diffusion welding of the 7B04, 2B06 and 7050 aluminum alloys is realized through the steps, the welding rate of the welding joint reaches over 95 percent, the thinning rate is 7.2 percent, and the strength of the welding joint is 175.9 MPa.
And carrying out aging heat treatment on the welded 7B04, 2B06 and 7050 aluminum alloy welding test pieces in an air environment, keeping the temperature for 24 hours at 160 ℃ as a technological parameter, further improving the comprehensive mechanical property of the joint, and improving the strength of the joint from 175.9MPa to 208.6 MPa.
According to the five embodiments of the welding results of five groups of aluminum alloy joints (including welding in the same type and welding in different types), the non-vacuum welding method provided by the application can enable the welding rate of the aluminum alloy joint to reach more than 85%, meanwhile, the thinning rate and the shearing strength of the welding joint meet the welding standard, and the strength of the aluminum alloy joint is improved by at least 20MPa after postweld heat treatment.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and the present invention is also applicable to the prediction of lateral maneuver trajectory and target speed of hypersonic velocity target. Any modification, equivalent replacement, and improvement made within the spirit and scope of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. An aluminum alloy surface activation non-vacuum diffusion welding and subsequent heat treatment method is characterized in that: the method is realized by the following steps:
the method comprises the following steps: cleaning the surfaces to be welded of each aluminum alloy: mechanically grinding and polishing the surface of the aluminum alloy, and placing the aluminum alloy in an acetone solution to remove surface oil stains;
step two: removing the oxide film on the surface of the aluminum alloy: sequentially using an alkali solution and an acid solution to clean the aluminum alloy and removing an oxide film on the surface to be welded on the surface;
step three: carrying out electrodeposition of a copper film on the surface to be welded of the aluminum alloy;
in the third step, the copper film electrodeposited on the surface of the aluminum alloy to be welded uses a solution with copper sulfate as a main salt, and the process conditions are as follows: the current density is 3.2A/dm 2 The method is characterized in that 50ms is taken as a period, the on-off ratio is 3:2, a square wave and single pulse mode is adopted, the electrodeposition time is 15min, the temperature is 50 ℃, and the pH value is 8-9;
in the third step, the thickness of the plated film of the middle layer is adjusted by controlling the electrodeposition time, the thickness of the plated film is 10 mu m, and the size of the crystal grain is 30-50 nm;
step four: carrying out non-vacuum diffusion welding on the aluminum alloy joint sample;
step four, firstly: firstly, preheating a non-vacuum diffusion welding furnace;
in the fourth step, the preheating temperature of the non-vacuum diffusion welding furnace is 400 degrees;
step four and step two: after the temperature in the non-vacuum diffusion welding furnace reaches the preheating temperature, stacking an aluminum alloy sample with a copper film deposited on the surface as a component to be welded, placing the component in the diffusion welding furnace into the non-vacuum diffusion welding furnace, simultaneously heating to the target temperature and applying pressure, and performing diffusion welding in an air environment;
the welding process parameters in the fourth step and the second step are that the temperature is raised to 450-550 ℃, and the applied welding pressure is 5-10 MPa;
step four and step three: after the welding of the components is finished, heat preservation, pressure maintaining and shaping are carried out in a furnace:
the heat preservation time in the fourth step and the third step is 60-150 min;
step four: after heat preservation, pressure maintaining and shaping, gradually reducing the temperature in the furnace to a preheating temperature, taking out the workpiece subjected to heat preservation, pressure maintaining and shaping from the non-vacuum diffusion welding furnace, and immediately putting the next group of components to be welded into the diffusion welding furnace;
step four and five: repeating the steps, and welding the multiple groups of components to be welded one by one until the welding process of all the components to be welded is completed;
step five: carrying out aging heat treatment on the welded aluminum alloy sample;
and fifthly, performing aging heat treatment on the aluminum alloy sample after welding in an air environment, wherein the process parameters are heat preservation for 10 hours, 24 hours or 48 hours under the condition that the heat preservation temperature is 160 ℃.
2. The method for activated non-vacuum diffusion welding and subsequent heat treatment of aluminum alloy surface as claimed in claim 1, wherein: in the first step, abrasive paper with the mesh number from low to high is sequentially selected to mechanically polish and polish the surface of the aluminum alloy to be welded, and then the aluminum alloy is placed in an acetone solution to be ultrasonically cleaned, so that oil stains on the surface of the aluminum alloy are removed.
3. The method for activated non-vacuum diffusion welding and subsequent heat treatment of aluminum alloy surface as claimed in claim 2, wherein: and in the second step, the alkali solution is a sodium hydroxide solution, and the acid solution is a nitric acid solution.
4. The method for activated non-vacuum diffusion welding and subsequent heat treatment of aluminum alloy surface as claimed in claim 3, wherein: in the second step, the concentration of the sodium hydroxide solution is 15 wt.%, and the concentration of the nitric acid solution is 10 vol.%.
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