Vacuum metallurgical joining method of high-silicon aluminum alloy

Abstract

The application discloses a vacuum metallurgy connecting method of high-silicon aluminum alloy, and relates to the technical field of diffusion welding, and comprises the following steps: S1, a high-silicon aluminum alloy workpiece to be welded is subjected to pre-welding treatment in a mode of friction stir welding, so as to increase the content of aluminum elements on the surface of the high-silicon aluminum alloy workpiece to be welded; and S2, the high-silicon aluminum alloy workpiece to be welded subjected to the treatment in the step S1 is subjected to diffusion welding under vacuum conditions, so as to obtain a high-silicon aluminum alloy workpiece after welding. The application has the advantages that the operation is simple, before the diffusion welding of the high-silicon aluminum alloy with high content of silicon elements, a process metallurgy method is used to perform pre-welding treatment on the surface to be welded, so as to increase the content of aluminum elements on the welding surface, further increase the contact proportion of aluminum elements on the diffusion welding surface, and finally realize the increase of the strength of the diffusion welding joint. That is, the advantages of the high-silicon aluminum alloy material are maintained, and the strength of the diffusion welding joint is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diffusion welding, more particularly to the technical field of vacuum metallurgical connection method of high-silicon aluminum alloy. BACKGROUND

[0002] Silicon-aluminum alloy is a binary alloy composed of silicon and aluminum, which is a metal-based thermal management material mainly used for alloy materials of aerospace, space technology and portable electronic devices. High-silicon aluminum alloy material can maintain the excellent performance of silicon and aluminum, and the content of silicon and aluminum is quite rich, the preparation technology of silicon powder is mature, and the cost is low. At the same time, this material has no pollution to the environment and is harmless to the human body. The density of high-silicon aluminum alloy is between 2.4~2.7g / cm³, and the coefficient of thermal expansion (CTE) is between 7~20ppm / ℃, and the density and thermal expansion coefficient of the alloy material can be significantly reduced by increasing the silicon content. Among them, the silicon content of more than 22% is called high-silicon aluminum alloy, and the main content is 25%~70%.

[0003] For the composite connection of metals, welding is generally used, and the common welding methods include argon arc welding, brazing, diffusion welding, electron beam welding, friction stir welding, etc. Since silicon and aluminum will produce eutectic reaction at 577℃, the welding method is not suitable for the welding of high-silicon aluminum alloy, the available brazing filler metal is less, and it is all low-temperature filler metal, so the strength of the welded joint after welding is low, so the brazing method is generally not used. Friction stir welding is an effective and feasible welding method, but the structure that can be welded is limited, and the welding depth is limited, so it is not used.

[0004] Diffusion welding is to tightly press two workpieces to be welded together and place them in a vacuum or protective atmosphere furnace for heating, so that the small unevenness of the two welding surfaces produces micro-plastic deformation to achieve close contact. In the subsequent heating and holding, atoms diffuse to each other to form a metallurgical connection. The diffusion welding process can be divided into three stages. The first stage is the physical contact stage. Under the action of pressure and temperature, some points on the connected surface first reach plastic deformation. Under the action of continuous pressure, the contact area gradually expands to finally achieve reliable contact of the whole surface. The second stage is the mutual diffusion of atoms in the contact interface to form a firm bonding layer. The third stage is that the bonding layer formed in the contact part gradually develops in the volume direction to form a reliable connection joint. Of course, the three processes are not completely separated, but are interlaced, and finally form a solid-state metallurgical bond in the joint connection area due to diffusion, recrystallization and other processes. It can generate solid solution and eutectic, and sometimes generate intermetallic compound to form reliable connection.

[0005] Diffusion welding is a solid-phase connection, and the welding temperature is lower than the melting point of the workpiece. The diffusion welding method is used for welding high-silicon aluminum alloy, and the welding temperature is lower than the eutectic reaction temperature of silicon and aluminum (577 DEG C), so that the eutectic reaction of silicon and aluminum does not occur during welding.

[0006] In the diffusion welding connection of high-silicon element content silicon aluminum alloy, the content of silicon element is high, when the two blank welding surfaces contact, the contact proportion of silicon element and silicon element is large, the silicon atom is relatively stable and not easy to diffuse with each other, the welding rate after welding is low, it is not easy to form a stable welding joint, and the strength of the weld position is low. SUMMARY

[0007] The purpose of the present application is to solve the technical problems of low welding surface welding rate, not easy to form a stable welding joint and low strength of the weld position in the diffusion welding connection of high-silicon element content silicon aluminum alloy, the present application provides a vacuum metallurgical connection method of high-silicon aluminum alloy. The strength of the weld position is improved, and the quality reliability of the high-silicon aluminum component is improved. Before diffusion welding, the welding surface of the high-silicon element content silicon aluminum alloy to be welded is treated before welding, and the content of aluminum element on the welding surface is improved.

[0008] In order to achieve the above purpose, the present application specifically adopts the following technical scheme:

[0009] The present application provides a vacuum metallurgical connection method of high-silicon aluminum alloy, comprising the following steps:

[0010] S1, the welding surface of the high-silicon aluminum alloy workpiece to be welded is treated before welding by friction stir welding, so as to improve the content of aluminum element on the welding surface of the high-silicon aluminum alloy workpiece to be welded;

[0011] S2, the high-silicon aluminum alloy workpiece to be welded treated in step S1 is diffusion welded under vacuum condition, and the high-silicon aluminum alloy workpiece after welding is obtained.

[0012] In one embodiment, in step S1, the welding surface of the high-silicon aluminum alloy workpiece to be welded is treated before welding by friction stir welding, and mode one is as follows:

[0013] A plurality of auxiliary holes are processed on the welding surface of the high-silicon aluminum alloy workpiece to be welded, the depth of the auxiliary hole is 2 / 5~1 / 2 of the height of the stirring pin, the radius of the auxiliary hole is 1 / 2~1 / 3 of the radius of the stirring pin, the distance between the center of the outermost auxiliary hole and the edge of the high-silicon aluminum alloy workpiece to be welded is greater than the radius of the shoulder, the distance between the centers of the two adjacent auxiliary holes on the inside is not less than the diameter of the shoulder, the auxiliary hole is filled with aluminum powder, and the aluminum powder and the high-silicon aluminum alloy workpiece to be welded are welded into one body by friction stir welding.

[0014] In one embodiment, the specific steps of mode one are as follows:

[0015] S11, using high silicon element content of silicon aluminum alloy raw material, processing into blank, that is, processing the base plate and the cover plate;

[0016] S12, processing the auxiliary hole on the surface to be welded of the blank, and paying attention to not processing the hole on the edge of the blank during processing;

[0017] S13, filling the aluminum powder in the auxiliary hole of the blank;

[0018] S14, using the friction stir welding equipment, friction stir welding the blank after processing the auxiliary hole and the filled aluminum powder;

[0019] S15, adopting numerical control cutting to process the surface to form the diffusion welding smooth surface, the cutting processing depth is less than the depth of the auxiliary hole before the friction stir welding, and the roughness of the diffusion welding surface to be welded is better than 1.6 and the flatness is 0.05;

[0020] S16, ultrasonic cleaning, to obtain the workpiece after welding processing;

[0021] S17, diffusion welding the workpiece after welding processing.

[0022] In an embodiment, in step S1, the workpiece to be welded of high silicon aluminum alloy is processed before welding by the way of friction stir welding, and the second way is as follows:

[0023] uniformly distributed grooves are processed on the surface to be welded of the workpiece to be welded of high silicon aluminum alloy, the depth of the groove is 2 / 5~1 / 2 of the height of the stirring pin, the width of the groove is 2 / 5~1 / 2 of the diameter of the stirring pin, the distance between the center line of the outermost groove and the edge of the workpiece to be welded of high silicon aluminum alloy is greater than the radius of the shaft shoulder, the distance between the center lines of the two adjacent inner grooves is not less than the diameter of the shaft shoulder, the groove is filled with aluminum powder, and the aluminum powder and the workpiece to be welded of high silicon aluminum alloy are welded into one by friction stir welding.

[0024] In an embodiment, the specific steps of the second way are as follows:

[0025] S11, using high silicon element content of silicon aluminum alloy raw material, processing into blank, that is, processing the base plate and the cover plate;

[0026] S12, processing the groove on the surface to be welded of the blank, and paying attention to not processing the groove on the edge of the blank during processing;

[0027] S13, filling the aluminum powder in the groove of the blank;

[0028] S14, using the friction stir welding equipment, friction stir welding the blank after processing the groove and the filled aluminum powder;

[0029] S15, adopt numerical control cutting processing surface to form diffusion welding light surface, cutting processing depth is less than the depth of the groove before friction stir welding, ensure that the roughness of the diffusion welding surface to be welded is better than 1.6, and the flatness is 0.05;

[0030] S16, ultrasonic cleaning, to obtain the workpiece after welding treatment;

[0031] S17, diffusion welding of the workpiece after welding treatment.

[0032] In one embodiment, in step S1, the workpiece to be welded of high-silicon aluminum alloy is treated before welding by friction stir welding, and mode three is as follows:

[0033] A pure aluminum plate is placed on the surface to be welded of the workpiece to be welded of high-silicon aluminum alloy, the length and width dimensions of the pure aluminum plate are the same as those of the surface to be welded of the workpiece to be welded of high-silicon aluminum alloy, and the thickness of the pure aluminum plate is less than the height of the stirring needle, generally within 1.5 mm. There is no special requirement for the selection of the diameter of the stirring needle and the diameter of the shoulder. The pure aluminum plate and the workpiece to be welded of high-silicon aluminum alloy are welded into one body by friction stir welding.

[0034] In one embodiment, the specific steps of mode three are as follows:

[0035] S11, using a high-silicon element content silicon-aluminum alloy raw material to process a blank, i.e., to process a base plate and a cover plate;

[0036] S12, using a pure aluminum raw material to process a pure aluminum plate;

[0037] S13, assembling the blank and the pure aluminum plate, and clamping them using a friction stir welding clamp to prevent relative movement between the two during the friction stir welding process;

[0038] S14, friction stir welding the blank and the pure aluminum plate;

[0039] S15, adopt numerical control cutting processing surface to form diffusion welding light surface, cutting processing depth is less than the depth of the groove before friction stir welding, ensure that the roughness of the diffusion welding surface to be welded is better than 1.6, and the flatness is 0.05;

[0040] S16, ultrasonic cleaning, to obtain the workpiece after welding treatment;

[0041] S17, diffusion welding of the workpiece after welding treatment.

[0042] In one embodiment, in step S1, the workpiece to be welded of high-silicon aluminum alloy is treated before welding by friction stir welding, and mode four is as follows:

[0043] The high-silicon aluminum alloy workpiece to be welded is subjected to friction stir welding on the surface to be welded by using a needle-free hollow stirring head, pure aluminum material is selected for the material in contact with the surface to be welded inside the stirring head, the pure aluminum material region of the stirring head is abraded by friction with the surface to be welded of the high-silicon aluminum alloy workpiece during welding, and the abraded pure aluminum material is welded with the high-silicon aluminum alloy workpiece to be welded as a whole, thereby increasing the aluminum element content on the surface of the workpiece.

[0044] In one embodiment, the implementation steps of mode four are as follows:

[0045] S11, using high-silicon element content silicon aluminum alloy raw material, processing into blank, that is, processing base plate and cover plate;

[0046] S12, friction stir welding the surface to be welded of the blank, the type of stirring head is selected as a needle-free hollow stirring head, and the material in contact with the surface to be welded of the blank inside the stirring head is pure aluminum material;

[0047] S13, forming a diffusion welding smooth surface by numerical control cutting processing, and the cutting processing depth is required to be as small as possible under the condition that the roughness of the diffusion welding surface to be welded is better than 1.6 and the flatness is 0.05;

[0048] S14, ultrasonic cleaning, to obtain the workpiece after welding pretreatment;

[0049] S15, diffusion welding the workpiece after welding pretreatment.

[0050] Modes one to four all use silicon aluminum alloy with a silicon element content of 50 or higher, and the surface to be welded is subjected to welding pretreatment by using the friction stir welding method, so that the aluminum element content of the surface to be welded is increased. During the friction stir welding process, the stirring head has a downward pressure on the blank, and after the friction stir welding is completed, there are pits on the surface to be welded, and the flatness and roughness are poor. The surface to be welded is subjected to smooth surface treatment by using numerical control processing equipment, the flatness and roughness of the surface to be welded are improved, and the cutting processing depth is less than the depth of the pretreatment layer. On this basis, the workpiece is subjected to ultrasonic cleaning, and then diffusion welding is performed. Compared with before the welding pretreatment, the contact ratio of the aluminum element of the diffusion welding surface to the aluminum element is increased, the bonding rate of the welding surface is increased, and the strength of the diffusion welding joint is increased.

[0051] The beneficial effects of the present application are as follows:

[0052] 1. The present application is simple to operate, before diffusion welding of high-silicon element content silicon aluminum alloy, a process metallurgy method is used for welding pretreatment on the surface to be welded, the aluminum element content of the welding surface is increased, the contact ratio of the aluminum element of the diffusion welding surface to the aluminum element is increased, and finally the strength of the diffusion welding joint is increased. That is, the advantages of high-silicon aluminum alloy material are maintained, and the strength of the diffusion welding joint is increased.

[0053] 2. Low cost. The price of aluminum powder and pure aluminum plate is low, the cost of friction stir welding is low, and the cost of the method is low.

[0054] 3. In the process of pre-treatment of friction stir welding, the effect of refining grains is realized, and the strength of high-silicon aluminum alloy is improved.

[0055] 4. The machining smooth surface action in the application can effectively reduce the stress level of the component and homogenize the stress distribution, and significantly reduce deformation. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 It is a schematic diagram of the blank of example 1;

[0057] Figure 2 It is a schematic diagram after the auxiliary hole of example 1 is machined;

[0058] Figure 3 It is a schematic diagram of the base plate blank of example 2;

[0059] Figure 4 It is a schematic diagram of the cover plate blank of example 2;

[0060] Figure 5 It is a schematic diagram after the auxiliary hole of the base plate blank of example 2 is machined;

[0061] Figure 6 It is a schematic diagram after the auxiliary hole of the cover plate of example 2 is machined;

[0062] Figure 7 It is a schematic diagram of the base plate blank of example 3;

[0063] Figure 8 It is a schematic diagram of the cover plate blank of example 3;

[0064] Figure 9 It is a schematic diagram after the groove of the base plate and the cover plate of example 3 is machined;

[0065] Figure 10 It is a schematic diagram of the base plate blank of example 4;

[0066] Figure 11 It is a schematic diagram of the cover plate blank of example 4;

[0067] Figure 12 It is a schematic diagram of the base plate blank of example 5;

[0068] Figure 13 It is a schematic diagram of the cover plate blank of example 5;

[0069] Figure 14 It is a schematic diagram of the blank of example 6;

[0070] Figure 15 Cover blank part schematic diagram for example 6. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0072] Example 1

[0073] In this example, two pieces of silicon-aluminum alloy 50 plates with a size of 88mm x 56mm x 10mm are diffusion welded. The 88mm x 56mm plane is the welding plane.

[0074] The high-silicon aluminum alloy workpiece to be welded is pre-welded by friction stir welding. The specific operation steps of mode one are as follows:

[0075] Step 1: Use silicon-aluminum alloy 50 as raw material to process two pieces of pre-welding blank parts (base plate and cover plate) with a size of 88mm x 56mm x 10mm. The structure schematic diagram of the blank part is shown in Figure 1 In this example, the base plate and the cover plate for diffusion welding have the same shape and size;

[0076] Step 2: Process auxiliary holes on the 88mm x 56mm plane of the blank part. The size of the auxiliary hole is Φ2mm x 1.5mm, and the distance between the centers of two adjacent auxiliary holes is 8mm. The structure schematic diagram of the blank part after processing the auxiliary hole is shown in Figure 2

[0077] Step 3: Fill the Φ2mm x 1.5mm auxiliary hole with aluminum powder;

[0078] Step 4: Use the friction stir welding equipment to stir and friction weld the silicon-aluminum alloy 50 and the aluminum powder on the 88mm x 56mm plane where the auxiliary hole is processed to make them into one, so as to realize the pre-welding treatment of the plane. The specification of the stir head used is: the shoulder diameter is 8mm, the stir pin diameter is 3mm, and the stir pin height is 3mm;

[0079] Step 5: Machine the diffusion welding surface to be welded to a smooth surface with a thickness of 1mm to ensure the roughness and flatness requirements of the diffusion welding. The specific requirements are: roughness 1.6, flatness 0.05;

[0080] ​Step 6, after friction stir welding, machining smooth surface, before diffusion welding, the workpiece is ultrasonic cleaned, the specific method is to clean for 10 minutes at room temperature environment;

[0081] Step 7, assemble two 88mmx56mmx10mm diffusion welding blanks, the 88mmx56mm plane which has been treated before welding is the diffusion welding surface. The assembled workpiece is welded using a vacuum diffusion welding device, and the diffusion welding is completed under the joint action of temperature and pressure.

[0082] Example 2

[0083] In this example, a circular workpiece with an internal structure is diffusion welded, the substrate size is Φ90mmx12mm, there is a long slot with a width of 6mm and a depth of 4mm in the middle position, and the cover plate size is Φ90mmx8mm.

[0084] The workpiece to be welded is treated before welding by friction stir welding, the specific operation steps of mode one are as follows:

[0085] Step 1, silicon aluminum alloy 50 raw material, machining substrate, cover plate before welding blank, the substrate blank schematic diagram is shown in Figure 3 , the cover plate blank schematic diagram is shown in Figure 4 ;

[0086] Step 2, process auxiliary holes on the cover plate blank to be welded, the size of the auxiliary hole is Φ1.9mmx1.6mm, the center distance between the two auxiliary holes is 8mm, the schematic diagram of the substrate blank after processing auxiliary holes is shown in Figure 5 , the schematic diagram of the cover plate blank after processing holes is shown in Figure 6 ;

[0087] Step 3, fill the auxiliary hole of Φ1.9mmx1.6mm with aluminum powder;

[0088] Step 4, use friction stir welding equipment to stir and friction weld silicon aluminum alloy 50 and aluminum powder on the substrate and cover plate to be welded respectively, so as to realize the pre-welding treatment of the substrate and cover plate to be welded. The specification of the stir head used is: the shoulder diameter is 8mm, the stir pin diameter is 3mm, and the stir pin height is 3mm;

[0089] Step 5, machine the diffusion welding surface of the substrate and cover plate to 1mm smooth surface, ensure the roughness to be 1.6 and the flatness to be 0.05;

[0090] Step 6, ultrasonic clean the substrate and cover plate, the specific cleaning method is to clean for 10 minutes at room temperature environment;

[0091] Step 7, assemble the substrate and the cover plate, and use the diffusion welding equipment to realize diffusion welding of the silicon-aluminum alloy 50 substrate and the cover plate.

[0092] Example 3

[0093] In this example, the raw material is a silicon-aluminum alloy 50 liquid cooling heat dissipation cold plate, the substrate has a size of 100mmx60mmx14mm and has a flow channel structure inside, and the substrate blank is as shown in Figure 7 The cover plate has a size of 100mmx60mmx14mm, and the cover plate blank is as shown in Figure 8 .

[0094] The high-silicon aluminum alloy workpiece to be welded is subjected to pre-welding treatment by friction stir welding, and the specific operation steps of mode two are as follows:

[0095] Step 1, use silicon-aluminum alloy 50 raw materials to process the cover plate blank, and only process the outer size of the substrate to be 100mmx60mmx14mm, and temporarily do not process the internal flow channel;

[0096] Step 2, process grooves on the 100mmx60mm welding surface of the substrate and the cover plate, and the depth of the grooves is 1.5mm. The grooves are composed of a rectangle of 2mmx48mm and two semicircles with a diameter of 2mm in the length and width directions, the distance between the outer groove center line and the edge is 6mm, the distance between the center of the diameter of 2mm semicircle and the edge is 6mm, and the distance between the center lines of adjacent grooves is 8mm. The blank after the substrate and the cover plate are processed with grooves is as shown in Figure 9 .

[0097] Step 3, fill the grooves with aluminum powder;

[0098] Step 4, use the friction stir welding equipment to friction stir weld the aluminum powder and the silicon-aluminum alloy 50 into one body, and realize the pre-welding treatment of the welding surface of the substrate and the cover plate. The specification of the stir head used is: the shoulder diameter is 8mm, the stir pin diameter is 3mm, and the stir pin height is 3mm;

[0099] Step 5, machine the substrate and the cover plate to have a smooth surface of 1mm on the diffusion welding surface, so as to ensure that the roughness is 1.6 and the flatness is 0.05;

[0100] Step 6, refer to Figure 7 , and process the flow channel structure inside the substrate;

[0101] Step 7, ultrasonic clean the substrate and the cover plate, and the specific cleaning method is to clean for 10 minutes at room temperature;

[0102] Step 8, assemble the substrate and the cover plate, and use the diffusion welding equipment to realize diffusion welding of the silicon-aluminum alloy 50 substrate and the cover plate.

[0103] Example 4

[0104] In this example, the silicon-aluminum alloy 50 structure with closed internal cavities is diffusion welded, the substrate has an outer size of Φ100mm x 20mm, a through hole with a diameter of Φ20mm in the middle, and four closed internal cavities, and the substrate blank is as shown in Figure 10 ; the cover plate has a size of Φ100mm x 20mm, and the cover plate blank is as shown in Figure 11 .

[0105] The high-silicon aluminum alloy workpiece to be welded is subjected to pre-welding treatment by friction stir welding, and the specific operation steps of mode three are as follows:

[0106] Step 1, process the cover plate blank, and only process the outer size Φ100mm x 20mm of the substrate, and temporarily do not process the internal cavities and through holes;

[0107] Step 2, process two pure aluminum plates with a size of Φ100mm x 1.2mm;

[0108] Step 3, assemble the silicon-aluminum alloy 50 blank and the pure aluminum plate, and use a friction stir welding clamp to clamp them, so that they do not move relative to each other during the friction stir welding process;

[0109] Step 4, use friction stir welding to weld the substrate and the pure aluminum plate, and the cover plate and the pure aluminum plate. The specifications of the stir head used are: the shoulder diameter is 8mm, the stir pin diameter is 2.5mm, and the stir pin height is 2.5mm;

[0110] Step 5, machine the diffusion welding surface of the substrate and the cover plate to a smooth surface of 0.8mm, with a roughness of 1.6 and a flatness of 0.05;

[0111] Step 6, refer to Figure 10 , process the internal cavities and through holes of the substrate;

[0112] Step 7, ultrasonic clean the substrate and the cover plate, and the specific cleaning method is to clean them with alcohol for 10 minutes in a room temperature environment;

[0113] Step 8, assemble the substrate and the cover plate, and use the diffusion welding equipment to realize the diffusion welding of the silicon-aluminum alloy 50 substrate and the cover plate.

[0114] Example 5

[0115] In this example, the silicon-aluminum alloy 50 with internal flow channel structure is diffusion welded, the substrate has an outer size of 70mm x 55mm x 15mm, and the substrate has a flow channel structure inside, and the substrate blank is as shown in Figure 12 ; the cover plate has a size of 70mm x 55mm x 10mm, and the cover plate blank is as shown in Figure 13 .

[0116] The high-silicon aluminum alloy workpiece to be welded is subjected to pre-welding treatment by means of friction stir welding, and the specific operation steps of mode three are as follows:

[0117] Step 1: Use silicon-aluminum alloy 50 raw materials to process cover plate blank parts. The base plate is only processed to have an outer dimension of 70mmx55mmx15mm, and the internal flow channel is temporarily not processed.

[0118] Step 2: Use pure aluminum raw materials to process two pure aluminum plates with a size of 70mmx55mmx1.2mm.

[0119] Step 3: Assemble the silicon-aluminum alloy 50 blank parts and the pure aluminum plates, and use a friction stir welding clamp to clamp them, so that the two do not move relative to each other during the friction stir welding process.

[0120] Step 4: Use friction stir welding to weld the base plate and the pure aluminum plate, and the cover plate and the pure aluminum plate. The specifications of the stir head used are: the shoulder diameter is 8mm, the stir pin diameter is 2.5mm, and the stir pin height is 2.5mm.

[0121] Step 5: Machine the base plate and the cover plate to have a diffusion welding surface of 0.8mm, with a roughness of 1.6 and a flatness of 0.05.

[0122] Step 6: Refer to Figure 12 to process the internal flow channel of the base plate.

[0123] Step 7: Ultrasonic clean the base plate and the cover plate. The specific cleaning method is to clean them in an alcohol solution at room temperature for 10 minutes.

[0124] Step 8: Assemble the base plate and the cover plate, and use a diffusion welding device to realize diffusion welding of the silicon-aluminum alloy 50 base plate and the cover plate.

[0125] Example 6

[0126] This example performs diffusion welding on a silicon-aluminum alloy 50 structure with a closed internal cavity. The base plate has an outer dimension of Φ90mmx14mm and an internal flow channel structure. The base plate blank part is shown in Figure 14 . The cover plate has a size of Φ90mmx14mm, and the cover plate blank part is shown in Figure 15 .

[0127] The high-silicon aluminum alloy workpiece to be welded is subjected to pre-welding treatment by means of friction stir welding, and the specific operation steps of mode four are as follows:

[0128] Step 1: Use silicon-aluminum alloy 50 raw materials to process cover plate blank parts. The base plate is only processed to have an outer dimension of Φ90mmx14mm, and the internal flow channel is temporarily not processed.

[0129] Step 2, stir friction welding of the workpiece to be welded of the silicon-aluminum alloy 50, the type of the stir head is selected as a hollow stir head without needle, the material in the stir head contacting the workpiece is pure aluminum material;

[0130] Step 3, machining a smooth surface of 0.8mm, ensuring that the roughness of the diffusion welding surface to be welded is 1.6 and the flatness is 0.05;

[0131] Step 4, ultrasonic cleaning of the workpiece after the stir friction welding and machining of the smooth surface;

[0132] Step 5, diffusion welding of the workpiece of the silicon-aluminum alloy 50 after the welding pre-treatment.

[0133] In summary, the specific embodiments of the present application are described, but the present application is not limited thereto, as long as the purpose of the present application is not deviated, the present application can also have various changes. For example, for the heat dissipation workpiece with a liquid cooling heat dissipation channel and a cavity type, the silicon-aluminum alloy 50 or the silicon-aluminum alloy with a higher content of silicon element can be pre-treated before welding, and then the channel and the cavity structure are processed. For another example, in the process of stir friction welding, the distance between the center of the outer hole, the center line of the outer groove and the edge can be reduced by adding a pilot block at the edge position. All these methods and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, which shall be within the protection scope of the present application.

Claims

1. A method for vacuum metallurgical joining of high-silicon aluminum alloys, characterized in that, It comprises the following steps: S1, the high-silicon aluminum alloy workpiece to be welded is treated by friction stir welding before welding, so as to increase the content of aluminum element on the surface of the high-silicon aluminum alloy workpiece to be welded; S2, the high-silicon aluminum alloy workpiece treated by step S1 is welded by diffusion welding under vacuum condition, so as to obtain the high-silicon aluminum alloy workpiece after welding.

2. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 1, characterized in that, In step S1, the high-silicon aluminum alloy workpiece to be welded is treated by friction stir welding before welding, and mode one is as follows: A plurality of auxiliary holes are processed on the surface of the high-silicon aluminum alloy workpiece to be welded, the auxiliary holes are filled with aluminum powder, and the aluminum powder and the high-silicon aluminum alloy workpiece to be welded are welded into one by friction stir welding.

3. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 2, characterized in that, The depth of the auxiliary hole is 2 / 5~1 / 2 of the height of the stirring pin, the radius of the auxiliary hole is 1 / 2~1 / 3 of the radius of the stirring pin, the distance between the center of the outermost auxiliary hole and the edge of the high-silicon aluminum alloy workpiece to be welded is greater than the shoulder radius, and the distance between the centers of the two adjacent auxiliary holes on the inside is not less than the shoulder diameter.

4. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 2 or 3, characterized in that, The specific steps of mode one are as follows: S11, using high-silicon element content silicon aluminum alloy raw material, processing into blank; S12, processing auxiliary holes on the surface of the blank to be welded; S13, filling the auxiliary holes of the blank with aluminum powder; S14, using friction stir welding equipment, welding the blank after processing the auxiliary holes and the filled aluminum powder by friction stir welding; S15, forming a diffusion welding smooth surface by numerical control cutting processing, and the cutting processing depth is less than the depth of the auxiliary hole before friction stir welding; S16, ultrasonic cleaning, to obtain the workpiece after welding treatment; S17, diffusion welding the workpiece after welding treatment.

5. The vacuum metallurgical joining method for high-silicon aluminum alloys according to claim 1, characterized in that, In step S1, the high-silicon aluminum alloy workpiece to be welded is treated by friction stir welding before welding, and mode two is as follows: A plurality of auxiliary holes are processed on the surface of the high-silicon aluminum alloy workpiece to be welded, the auxiliary holes are filled with aluminum powder, and the aluminum powder and the high-silicon aluminum alloy workpiece to be welded are welded into one by friction stir welding.

6. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 5, characterized in that, The specific steps of mode two are as follows: S11, using high-silicon element content silicon aluminum alloy raw material, processing into blank; S12, processing auxiliary holes on the surface of the blank to be welded; S13, filling the auxiliary holes of the blank with aluminum powder; S14, using friction stir welding equipment, welding the blank after processing the auxiliary holes and the filled aluminum powder by friction stir welding; S15, forming a diffusion welding smooth surface by numerical control cutting processing, and the cutting processing depth is less than the depth of the auxiliary hole before friction stir welding; S16, ultrasonic cleaning, to obtain the workpiece after welding treatment; S17, diffusion welding the workpiece after welding treatment.

7. The vacuum metallurgical joining method for high-silicon aluminum alloys according to claim 1, characterized in that, In step S1, the high-silicon aluminum alloy workpiece to be welded is treated by friction stir welding before welding, and mode three is as follows: Place a pure aluminum plate on the surface to be welded of the high-silicon aluminum alloy workpiece to be welded, the length and width dimensions of the pure aluminum plate are the same as those of the surface to be welded of the high-silicon aluminum alloy workpiece to be welded, and the thickness of the pure aluminum plate is less than the height of the stirring pin, and the pure aluminum plate and the high-silicon aluminum alloy workpiece to be welded are welded into one body by friction stir welding.

8. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 7, characterized in that, The specific steps of the third mode are as follows: S11, using a high-silicon element content silicon aluminum alloy raw material to process a blank; S12, using a pure aluminum raw material to process a pure aluminum plate; S13, assembling the blank and the pure aluminum plate, and clamping them using a friction stir welding clamp to prevent relative movement between the two during friction stir welding; S14, friction stir welding the blank and the pure aluminum plate; S15, forming a diffusion welding light surface by numerical control cutting processing of the surface, and the cutting processing depth is less than the thickness of the pure aluminum plate before friction stir welding; S16, ultrasonic cleaning to obtain a workpiece after pre-welding treatment; S17, diffusion welding the workpiece after pre-welding treatment.

9. The vacuum metallurgical joining method for high-silicon aluminum alloys according to claim 1, characterized in that, In step S1, the high-silicon aluminum alloy workpiece to be welded is pre-treated by friction stir welding, and the fourth mode is as follows: A needle-free hollow stirring head is used to friction stir weld the surface to be welded of the high-silicon aluminum alloy workpiece to be welded, the material in contact with the surface to be welded inside the stirring head is pure aluminum material, the pure aluminum material region of the stirring head is worn out by friction with the surface to be welded of the high-silicon aluminum alloy workpiece to be welded during the welding process, and the worn pure aluminum material is welded into one body with the high-silicon aluminum alloy workpiece to be welded, thereby increasing the aluminum element content of the surface of the workpiece.

10. A method of vacuum metallurgical joining of high-silicon aluminum alloys according to claim 9, characterized in that, The specific implementation steps of the method are as follows: S11, using a high-silicon element content silicon aluminum alloy raw material to process a blank, i.e., processing a base plate and a cover plate; S12, friction stir welding the surface to be welded of the blank, the type of the stirring head is selected to be a needle-free hollow stirring head, and the material in contact with the surface to be welded of the blank inside the stirring head is pure aluminum material; S13, forming a diffusion welding light surface by numerical control cutting processing of the surface; S14, ultrasonic cleaning to obtain a workpiece after pre-welding treatment; S15, diffusion welding the workpiece after pre-welding treatment.

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