A method of laser welding an aluminum alloy to an aluminosilicate glass

Abstract

The present application relates to a kind of laser welding method of aluminum alloy and aluminum-silicon glass, belong to laser technical field.The laser welding method of the present application includes the following steps, S1, according to the size, shape of aluminum alloy and aluminum-silicon glass to be welded, setting processing track, and carrying out welding fixture preparation;S2, the pretreatment operation of aluminum alloy and aluminum-silicon glass to be welded is carried out;S3, according to the pretreated aluminum alloy and aluminum-silicon glass in S2, clamping is carried out according to requirements using welding fixture, and welding preparation is well done;S4, set laser laser processing parameter;S5, laser is according to the processing track set in S1 to aluminum alloy and aluminum-silicon glass laser welding operation is carried out, and aluminum alloy-aluminum-silicon glass weldment is formed;S6, remove welding fixture, complete entire welding operation process.The aluminum alloy-aluminum-silicon glass weldment obtained by production can meet the high-standard quality requirement of high-end manufacturing industry to industry applied in aerospace etc.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser, and particularly relates to a laser welding method for aluminum alloy and aluminum-silicon glass. BACKGROUND

[0002] With the rapid development of modern electronic information technology, the application of aluminum-silicon glass and metal sealing in electronic components and semiconductor devices is more and more extensive.

[0003] An ideal electronic packaging material should meet the following performance requirements: ①a reasonable expansion coefficient, the expansion coefficients between the packaging material and the connector should be matched, so as to avoid the thermal stress caused by the difference between the thermal expansion coefficients of the two when welding or working, and thus the product is damaged; ②a good heat conduction performance, which can timely dissipate the large amount of heat generated by the semiconductor working, and thus protects the internal part from failure due to high temperature; ③a good airtightness, which can resist the influence of harmful environments such as high temperature, high humidity, corrosion and radiation on electronic devices; ④a high strength and rigidity, which plays a supporting and protecting role on the internal part of the assembly; ⑤a good processing forming and welding performance, so as to be processed into various complex shapes and facilitate welding packaging; ⑥for electronic packaging materials applied in the field of aviation and aerospace, the density requirement is as small as possible, so as to reduce the weight of the device. A large number of sealing connectors are used on various electronic equipment assemblies of aviation, aerospace and electronic units, and most of these sealing connectors are sealed and connected by using Kovar alloy and aluminum-silicon glass.

[0004] The metal-glass sealing connector has a large difference in expansion coefficient, and has poor matching performance when being welded and packaged with the Kovar alloy shell. After welding, the sealing performance is easily lost due to the large stress. At the same time, the Kovar alloy cannot meet the lightweight demand of aviation and aerospace, and has a low thermal conductivity, which will affect the service life of the product. The silicon-aluminum alloy has excellent properties such as controllable thermal expansion coefficient, good thermal conductivity, high specific strength and rigidity, good plating performance and good welding performance, and meets the requirements of the development direction of electronic packaging technology such as miniaturization, lightweight and high-density assembly. Therefore, the sealing process of the silicon-aluminum alloy and the aluminum-silicon glass is a research direction of the sealing connector.

[0005] The content of Al2O3 and SiO2 in the aluminum-silicon glass is very high, and the aluminum-silicon glass has good chemical stability, electrical insulation, mechanical strength and low thermal expansion coefficient, and is generally used for processing and manufacturing halogen lamp glass, screen cover plate, chemical pipeline, alkali-free substrate and alkali-free glass fiber, and belongs to special industrial aluminum-silicon glass. At the same time, the glass has the characteristics of high transparency and suitable chemical tempering, and is therefore widely used in the field of aviation and aerospace.

[0006] The traditional high-temperature brazing sealing technology cannot meet the sealing requirements of aluminum alloy and aluminum-silicon glass because the aluminum alloy has poor high-temperature resistance, and the maximum temperature cannot exceed 600℃. If the temperature is too high, the aluminum will become soft and melt. Meanwhile, the environment used by aerospace components is special, and the components need to withstand high temperature, high humidity, corrosion, radiation and other harmful environments. Unlike the glass and metal in the door frame and window, which can be sealed by using adhesive tape or sealant, the aluminum-silicon glass and metal sealing body used in the door frame and window has a narrow service temperature range, and there is no other factor interference (no high temperature, high humidity, corrosion, radiation and other harmful environments). Therefore, a sealing method with low sealing temperature and good sealing effect must be selected for sealing.

[0007] There are many sealing methods for aluminum-silicon glass and metal, and the most studied and mature method is matching sealing. In the matching sealing process, the metal is pre-oxidized to form a dense oxide film with appropriate thickness on the surface of the metal before sealing. Then the metal and the heated aluminum-silicon glass are placed in a high-temperature furnace, and the metal and the heated aluminum-silicon glass are combined by diffusion and melting. After a certain time of heat preservation, the metal-aluminum-silicon glass composite material is cooled to room temperature and taken out. However, the matching sealing process needs to be heated in the furnace and then cooled, so the production method using matching sealing needs a long production cycle. At the same time, the oxidation of aluminum alloy has an adverse effect on the brightness and other characteristics of the aluminum alloy, which is not conducive to regular production. In order to shorten the production cycle, speed up the production and ensure the service requirements of sealing, direct welding of metal and aluminum-silicon glass has become the mainstream of production. Another fatal problem for aluminum alloy is that aluminum alloy is not suitable for high-temperature oxidation.

[0008] In recent years, relevant researches have been made on the welding technology of metal and glass. For example, the welding process disclosed in the patent documents “Glass and metal vacuum diffusion welding process” (application number 200810243068.7) and “Glass and metal vacuum brazing process” (application number 200910234678.5) needs to be operated in a vacuum environment. However, the size of aluminum-silicon glass and metal is limited by the vacuum chamber, and some large-size materials cannot be welded by using this welding process. For example, the patent documents “Anodic welding method between metal and glass and ceramic” (application number 200310105894.2) and “Metal welding convex vacuum glass with sealing strip and mounting hole” (application number 201310298572.8) are limited by the size of the welding vacuum chamber, and the working hours are large. The sealing temperature required for brazing is high, which damages the performance of aluminum alloy, cannot quickly and effectively realize the welding of aluminum-silicon glass and metal, and cannot meet the high quality requirements of glass-sealing body in aerospace occasions.

[0009] Therefore, in order to break through the limitation of metal and aluminum-silicon glass high-temperature sealing in the aerospace department, avoid the influence of high-temperature brazing on the performance of the sealing body, solve the problem of excessive time consumption, and improve the quality of products, a simple and controllable welding method with good weld is needed to realize the excellent welding of metal and aluminum-silicon glass. SUMMARY

[0010] To solve the above technical problems, the application provides a laser welding method for aluminum alloy and aluminum-silicon glass, which fully utilizes the performance of aluminum-silicon glass and aluminum-silicon alloy, adopts laser direct melting welding, discards the traditional brazing method in a vacuum chamber and the method of high-temperature oxidation of aluminum alloy to form an oxide film and then sealing, and solves the problems of low sealing strength and size specification limitation of traditional sealing.

[0011] The first object of the application is to provide a laser welding method for aluminum alloy and aluminum-silicon glass, comprising the following steps,

[0012] S1, according to the size and shape of the aluminum alloy and aluminum-silicon glass to be welded, setting the machining track and preparing the welding fixture;

[0013] S2, pretreating the aluminum alloy and aluminum-silicon glass to be welded;

[0014] S3, clamping the aluminum alloy and aluminum-silicon glass pretreated in S2 according to the requirements by using the welding fixture, and preparing for welding;

[0015] S4, setting the laser processing parameters of the laser;

[0016] S5, the laser performs laser welding operation on the aluminum alloy and aluminum-silicon glass according to the machining track set in S1, forming an aluminum alloy-aluminum-silicon glass welding body;

[0017] S6, removing the welding fixture and completing the whole welding operation process.

[0018] In an embodiment of the application, in S1, the aluminum alloy and aluminum-silicon glass refer to all aluminum alloys and aluminum-silicon glasses that can be used in electronic products for aerospace occasions.

[0019] In an embodiment of the application, in S2, the pretreatment operation includes:

[0020] Carrying out gas deposition treatment on the aluminum alloy to be welded to form a layer of Ti-Ni-Nb film on the surface of the aluminum alloy;

[0021] Carrying out water washing and cooling air drying on the aluminum-silicon glass to be welded.

[0022] In one embodiment of the present application, the thickness of the Ti-Ni-Nb film is 5-20 microns. The thickness of the Ti-Ni-Nb film must be controlled during the vapor deposition process. If the Ti-Ni-Nb film is too thin, the bonding is difficult to achieve due to the small stress buffer zone, and the sealing strength is low. If the Ti-Ni-Nb film is too thick, the stress buffer zone is too large, and the effective bonding is difficult to achieve, and the sealing strength is low.

[0023] In one embodiment of the present application, in S3, the aluminum-silicon glass covers part of the surface of the aluminum alloy, the welding clamps are respectively pressed against the surface of the aluminum-silicon glass and the bottom surface of the aluminum alloy, a clamping force in the vertical direction is provided, the side of the aluminum alloy covered by the aluminum-silicon glass is the weld, and the welding operation area is located between the two welding clamps on the surface of the aluminum-silicon glass, and the weld is located in the welding operation area in the vertical direction.

[0024] In one embodiment of the present application, in S4, the laser is a solid-state laser with a wavelength of 800-1070 nm.

[0025] In one embodiment of the present application, in S4, the laser processing parameters are as follows: the laser scanning speed is 1-3 mm·s -1 -3.3 mm·s -1 , the focal length is -3 mm≤f≤0 mm, the laser power is 150-299 W, the pulse width is 0.1-20 Ms, and the frequency is 20-30 Hz.

[0026] In one embodiment of the present application, in S5, the laser welding operation is carried out in a protective atmosphere.

[0027] In one embodiment of the present application, the protective atmosphere is an argon atmosphere.

[0028] In one embodiment of the present application, in S5, the laser emits a laser beam that penetrates the aluminum-silicon glass and is directly focused on the surface of the aluminum alloy according to the processing track set in S1, melts the aluminum alloy, and then bonds the aluminum alloy with the aluminum-silicon glass.

[0029] The second object of the present application is to provide an aluminum alloy-aluminum-silicon glass welded body prepared by the laser welding method.

[0030] The technical solution of the present application has the following advantages compared with the prior art:

[0031] (1) The laser welding method of the present application has the following advantages in the welding of aluminum-silicon glass and aluminum alloy after depositing the Ti-Ni-Nb film: first, the traditional sealing of aluminum alloy and aluminum-silicon glass is high-temperature sealing, which is to first oxidize the aluminum alloy at high temperature to form an oxide film, and then seal at high temperature, but the melting point of aluminum alloy is only 660 DEG C. For example, the maximum temperature resistance of aluminum-silicon alloy is only 580 DEG C, and if the temperature exceeds this value, the aluminum in the aluminum-silicon alloy will melt and precipitate, causing changes in the material organization and deformation of the parts. This does not meet the requirements of precision parts in aerospace. Second, the traditional Kovar alloy in aviation is replaced by aluminum alloy, which is of great significance to weight reduction in aerospace. Third, the thermal expansion coefficient of aluminum-silicon alloy is about 115x10 -7 / ℃, the thermal expansion coefficient of Ni-Ti-Nb film is about 114.3x10 -7 / ℃ (temperature range 30 DEG C-300 DEG C). The thermal expansion coefficient of aluminum-silicon glass is about 42x10 -7 / ℃-50x10 -7 / ℃, and the thermal expansion coefficient of Ni-Ti-Nb film is between that of aluminum-silicon alloy and aluminum-silicon glass.

[0032] (2) The laser welding method of the present application uses laser direct melting method to weld aluminum alloy and aluminum-silicon glass, which abandons the traditional vacuum sealing method, solves the size limitation and vacuum chamber condition limitation when using vacuum equipment, and also avoids the disadvantages of poor bonding strength and easy aging of the sealing strip. It also solves the problem of damage to the performance of aluminum alloy caused by high temperature in traditional brazing. Through optimization of process parameters, aluminum alloy and aluminum-silicon glass of different size specifications can be welded and prepared, which has the advantage of high controllability. The aluminum alloy-aluminum-silicon glass welding body produced can meet the high standard quality requirements of high-end manufacturing industries such as aerospace. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0034] Fig. 1 is a schematic diagram of the position of aluminum alloy and aluminum-silicon glass during welding of the present application;

[0035] Fig. 2 is a schematic diagram of the position of aluminum alloy, aluminum-silicon glass and welding fixture during welding of the present application;

[0036] BRIEF DESCRIPTION OF DRAWINGS: 1-laser beam, 2-aluminum-silicon glass, 3-aluminum alloy, 4-welding seam, 5-welding fixture, 6-clamping force. DETAILED DESCRIPTION

[0037] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand and implement the present application, but the embodiments are not intended to limit the present application.

[0038] In the present application, unless otherwise specified, the aluminum alloy and aluminum-silicon glass used in the embodiments refer to all aluminum alloys and aluminum-silicon glasses that can be used in electronic products in the fields of aerospace, etc.

[0039] Embodiment 1

[0040] Referring to Figs. 1-2 The laser welding method of the aluminum alloy and the aluminum-silicon glass of the present application specifically comprises the following steps:

[0041] S1, according to the size and shape of the aluminum alloy and the aluminum-silicon glass to be welded, the machining track is set, and the welding clamp is prepared;

[0042] S2, the aluminum alloy and the aluminum-silicon glass to be welded are subjected to preliminary welding pretreatment operation; the preliminary pretreatment refers to subjecting the aluminum alloy to vapor deposition treatment to form a Ti-Ni-Nb film with a thickness of 5-6 μm on the surface of the aluminum alloy; the aluminum-silicon glass is subjected to simple surface water washing, and then is blown dry by cold air for use;

[0043] S3, the welding clamp clamps the aluminum alloy and the aluminum-silicon glass subjected to the pretreatment operation in S2 according to the requirements, and makes good welding preparation, the aluminum-silicon glass 2 is covered on part of the surface of the aluminum alloy 3, the welding clamp 5 abuts against the surface of the aluminum-silicon glass 2 and the bottom surface of the aluminum alloy 3 respectively, and provides clamping force 6 in the vertical direction, the side of the aluminum alloy 3 covered is the weld 4, and the welding operation area exists between the two welding clamps 5 on the surface of the aluminum-silicon glass 2, and the weld 4 is located in the welding operation area in the vertical direction;

[0044] S4, the laser machining parameters are set: the laser adopts a solid laser with a wavelength of 800 nm, the laser machining parameters are set as follows: the laser scanning speed is 1 mm·s -1 , the focal length f=0 mm, the laser power is 150 W, the pulse width is 20 Ms, and the frequency is 20 Hz.

[0045] S5, the laser emits the laser beam 1 according to the machining track set in S1, the laser beam 1 penetrates the aluminum-silicon glass 2 and is focused directly on the surface of the aluminum alloy 3, the Ti-Ni-Nb film on the surface of the aluminum alloy 3 is melted to be joined with the aluminum-silicon glass 2, and the aluminum alloy-aluminum-silicon glass welding body is formed, the whole laser welding operation is carried out in the atmosphere of argon, and the Ti-Ni-Nb film plays the role of "glue" here;

[0046] S6, the welding clamp is removed, and the whole welding operation process is completed.

[0047] Tested:

[0048] The sealing strength is 31Mpa, and as a comparison, the strength of the welding after forming an oxide film on the surface of the aluminum alloy is 6Mpa.

[0049] After being kept in the open water at 100℃ for 10min, the welded body is taken out and cleaned with clean water, and the coloring is checked for cracks; the welded body of the embodiment can appear visible cracks after 10 cycles, and the traditional welded body without using the process can appear cracks only after 2 times.

[0050] Example 2

[0051] The laser welding method of the aluminum alloy and the aluminum-silicon glass of the application specifically comprises the following steps:

[0052] The same as example 1, except that the thickness of the Ti-Ni-Nb film is 10-11μm, the laser adopts a solid laser with a wavelength of 900nm, the laser processing parameters are set as follows: the laser scanning speed is 1.3mm·s -1 , the focal length f=-1mm, the laser power is 189W, the pulse width is 0.5Ms, and the frequency is 24Hz.

[0053] Tested:

[0054] The sealing strength is 36Mpa, and as a comparison, the strength of the welding after forming an oxide film on the surface of the aluminum alloy is 7Mpa.

[0055] After being kept in the open water at 100℃ for 10min, the welded body is taken out and cleaned with clean water, and the coloring is checked for cracks; the welded body of the embodiment can appear visible cracks after 10 cycles, and the traditional welded body without using the process can appear cracks only after 2 times.

[0056] Example 3

[0057] The laser welding method of the aluminum alloy and the aluminum-silicon glass of the application specifically comprises the following steps:

[0058] The same as example 1, except that the thickness of the Ti-Ni-Nb film is 15-16μm, the laser adopts a solid laser with a wavelength of 950nm, the laser processing parameters are set as follows: the laser scanning speed is 2.5mm·s -1 , the focal length f=-2mm, the laser power is 229W, the pulse width is 10Ms, and the frequency is 28Hz.

[0059] Tested:

[0060] The sealing strength is 39 Mpa, and the sealing strength of the aluminum alloy after forming an oxide film on the surface and then welding is 8 Mpa.

[0061] After being kept at 100 DEG C for 10 minutes, the welded body is taken out and cleaned with water, and then coloring is performed to check whether there is crack; the welded body of the embodiment can appear visible crack after 15 cycles, and the conventional welded body without using the process appears crack only after 3 times.

[0062] Example 4

[0063] The laser welding method of the aluminum alloy and the aluminum-silicon glass comprises the following steps:

[0064] The embodiment 1 is basically the same, except that the thickness of the anodic oxide film is 18-19 mu m, the laser is a solid laser with a wavelength of 1060 nm, the laser processing parameters are set as follows: laser scanning speed is 3.3 mm / s -1 , focal length f = -3 mm, laser power is 290 W, pulse width is 18 ms, and frequency is 30 Hz.

[0065] After testing:

[0066] The sealing strength is 33 Mpa, and the sealing strength of the aluminum alloy after forming an oxide film on the surface and then welding is 9 Mpa.

[0067] After being kept at 100 DEG C for 10 minutes, the welded body is taken out and cleaned with water, and then coloring is performed to check whether there is crack; the welded body of the embodiment can appear visible crack after 15 cycles, and the conventional welded body without using the process appears crack only after 3 times.

[0068] In summary, the laser welding method of the aluminum alloy and the aluminum-silicon glass provided by the application uses a laser direct melting method to weld the aluminum alloy and the aluminum-silicon glass, avoids the drawbacks of traditional aluminum alloy and aluminum-silicon glass welding, such as the need to be placed in a heat treatment furnace and a vacuum furnace for heat preservation to realize welding, breaks through the size limitation and the condition limitation of the vacuum chamber when using a vacuum device, and avoids the drawbacks of poor bonding strength, easy aging, and environmental pollution when sealing with a rubber strip, and the aluminum alloy and the aluminum-silicon glass of different sizes can be welded and prepared by optimizing the process parameters, and the aluminum alloy-aluminum-silicon glass welded body can meet the high-standard quality requirements of the high-end manufacturing industry such as aerospace.

[0069] Obviously, the above embodiments are merely example for clearly illustrating, and are not limitation to the embodiments. For ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and can not be exhausted. The obvious changes or variations derived therefrom are still within the scope of the present invention.

Claims

1. A laser welding method for aluminum-silicon alloy and aluminum-silicon glass, characterized in that, Includes the following steps, S1. Based on the dimensions and shape of the aluminum-silicon alloy and aluminum-silicon glass to be welded, set the processing trajectory and prepare the welding fixture; the coefficient of thermal expansion of the aluminum-silicon alloy is 115×10⁻⁶. -7 / ℃; S2. Pre-treatment of the aluminum-silicon alloy and aluminum-silicon glass to be welded; the pre-treatment includes: performing vapor deposition on the aluminum-silicon alloy to form a Ti-Ni-Nb film on its surface; washing the aluminum-silicon glass with water and cooling it to air dry; the thickness of the Ti-Ni-Nb film is 5μm-20μm, and the coefficient of thermal expansion is 114.3×10⁻⁶. -7 / ℃ S3. Use welding fixtures to clamp the pretreated aluminum-silicon alloy and aluminum-silicon glass from S2 as required, and prepare for welding. S4. Set the laser processing parameters; S5. The laser performs laser welding operation on aluminum-silicon alloy and aluminum-silicon glass according to the processing trajectory set in S1 to form an aluminum-silicon alloy-aluminum-silicon glass weld body. S6. Remove the welding fixture to complete the entire welding operation.

2. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 1, characterized in that, In S3, aluminosilicate glass covers part of the surface of the aluminosilicate alloy. Welding fixtures abut against the surface of the aluminosilicate glass and the bottom surface of the aluminosilicate alloy respectively, providing clamping force in the vertical direction. The side of the aluminosilicate alloy that is covered is the weld. There is a welding operation area between the two welding fixtures on the surface of the aluminosilicate glass. The weld is located in the weld operation area in the vertical direction.

3. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 1, characterized in that, In S4, the laser is a solid-state laser with a wavelength of 800nm-1070nm.

4. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 1, characterized in that, In S4, the laser processing parameters are: laser scanning speed is 1 mm·s. -1 -3.3mm·s -1 The focal length is -3mm≤f≤0mm, the laser power is 150W-299W, the pulse width is 0.1Ms-20Ms, and the frequency is 20Hz-30Hz.

5. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 1, characterized in that, In S5, the laser welding operation is performed in a protective atmosphere.

6. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 5, characterized in that, The protective atmosphere is an argon atmosphere.

7. The laser welding method for aluminum-silicon alloy and aluminum-silicon glass according to claim 1, characterized in that, In S5, the laser follows the processing trajectory set in S1. The laser beam emitted by the laser penetrates the aluminosilicate glass and is directly focused on the surface of the aluminosilicate alloy, melting it and bonding it with the aluminosilicate glass.

8. An aluminum-silicon alloy-aluminum-silicon glass weld body prepared by the laser welding method according to any one of claims 1-7.

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