Sapphire and metal welding method and welding joint

Abstract

The invention relates to the technical field of laser welding, in particular to a sapphire and metal welding method and a welding joint. The welding method comprises the following steps that S1, sapphire and metal are cleaned and dried, and the surface roughness Ra of the to-be-welded surface of the metal ranges from 0.5 micrometer to 1.6 micrometers; s2, the sapphire and the metal are stacked together, the to-be-welded face of the sapphire makes contact with the to-be-welded face of the metal, pressure is applied to the to-be-welded face of the sapphire and the to-be-welded face of the metal, and interface pressure is generated at a welding interface; and S3, welding is conducted, specifically, under the inert atmosphere, the to-be-welded areas of the sapphire and the metal are welded through the femtosecond laser welding technology. According to the method, the interface pressure is introduced to assist the femtosecond laser welding technology, the shearing strength of a welding joint is improved, the requirement for the surface roughness of a welding material is lowered, and on the basis that the welding quality is guaranteed, the machining difficulty is lowered, and the machining efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of laser welding technology, and more specifically, to a method for welding sapphire to metal and a welded joint. Background Technology

[0002] Sapphire (also known as corundum) is an inorganic non-metallic material composed of single-crystal α-Al₂O₃, with an Al₂O₃ content as high as 99.99%. Sapphire possesses excellent physical and chemical properties, including a hardness second only to diamond, stable chemical properties, good mechanical properties, and high-temperature resistance. Furthermore, sapphire exhibits excellent light transmittance in the ultraviolet to infrared region, reaching up to 87%, thus finding wide application in fields such as electronic component packaging substrates, hypersonic aircraft fairings, and optical windows.

[0003] In sapphire applications, the need for bonding with metallic materials is particularly prominent. Metal-sapphire bonding is commonly used in infrared detector windows, high-power waveguide windows, electronic devices, and vacuum equipment. Therefore, metal-sapphire bonding is of great significance to the development of aerospace and other related industries. Ultrafast lasers possess high energy densities (typically reaching megawatts or GW / cm²). 2 (Intensity), pulse duration is extremely short (up to 10) -15 With advantages such as high speed, low temperature, low heat-affected zone (laser focal diameter is a few micrometers to tens of micrometers), non-contact heating, and high flexibility, it can induce nonlinear absorption effects and local phase transitions in transparent materials, making it one of the most promising methods for processing hard and brittle materials.

[0004] However, existing ultrafast laser welding technology for joining sapphire and metal requires extremely high surface roughness on both materials, necessitating optical contact or nanoscale roughness. This not only increases processing difficulty and reduces efficiency but may also lead to inconsistent processing quality, limiting its widespread industrial application. Therefore, providing a welding method for sapphire and metal that reduces the surface roughness requirements on both materials while ensuring weld strength is of great significance.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a welding method and weld joint for sapphire and metal. By introducing interfacial pressure-assisted femtosecond laser welding technology, this invention improves the shear strength of the weld joint, reduces the requirements for the surface roughness of the welding material, and improves processing efficiency, process stability and welding quality.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A method for soldering sapphire to metal, comprising the following steps: S1. Pretreatment: cleaning and drying the sapphire and metal, wherein the surface roughness Ra of the metal to be soldered is 0.5μm-1.6μm; S2. Assembly: The pretreated sapphire and the metal are stacked together, so that the solderable surface of the sapphire comes into contact with the solderable surface of the metal, and pressure is applied to them to generate interfacial pressure at the soldering interface. S3. Welding: Under an inert atmosphere, femtosecond laser welding is used to weld the areas to be welded of the sapphire and the metal.

[0008] Preferably, the surface roughness Ra of the sapphire surface to be soldered is 0.3μm-0.5μm.

[0009] Preferably, the thickness of the sapphire is 1-5 mm.

[0010] Preferably, the sapphire is able to transmit light in the range of 300nm-5000nm, and has a transmittance greater than 87%.

[0011] Preferably, the metal includes at least one of titanium alloy, copper, and Invar alloy.

[0012] Preferably, in step S2, the applied pressure S0 satisfies: S-0.27≤S0≤S+0.27; in, , The unit of S is MPa, Ra 金 α is the surface roughness of the metal to be welded, in μm; HV is the Vickers hardness of the metal, in MPa; E is the elastic modulus of the metal, in GPa; α, β, and γ are material constants: when the metal is a titanium alloy, α = 0.035, β = 0.25, γ = 0.15; when the metal is an Invar alloy, α = 0.028, β = 0.20, γ = 0.20; when the metal is copper, α = 0.015, β = 0.15, γ = 0.10.

[0013] Preferably, the laser power of the femtosecond laser welding is 4.8W-14.0W, the scanning speed is 10mm / s-15mm / s, the laser pulse width is 200fs-500fs, and the laser repetition frequency is 1MHz-20MHz.

[0014] Preferably, the laser wavelength of the femtosecond laser welding is 1025nm-1035nm, and the laser focal position is -0.01mm to +0.01mm.

[0015] Preferably, the scanning line spacing of the femtosecond laser welding is 50μm-100μm.

[0016] A method for welding sapphire and titanium alloy, wherein the welding is performed using any one of the aforementioned embodiments.

[0017] A welded joint is obtained by welding using any one of the aforementioned embodiments.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention introduces interfacial pressure-assisted femtosecond laser welding technology to weld sapphire and metals, reducing the requirements for the surface roughness of the welding materials. It can weld metal materials and sapphire with surface roughness at the micrometer level, eliminating the need for strict nanoscale surface treatment of the welding materials, reducing processing difficulty, and improving processing efficiency. Through interfacial pressure assistance, the welding quality and process stability are improved, and the shear strength of the weld joint is significantly increased. Furthermore, the introduction of inert gas during femtosecond laser welding provides energy protection and prevents material oxidation during the welding process, further improving the welding quality. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of an ultrafast laser welding method provided in an embodiment of the present invention; Figure 2 These are surface morphology images of the sapphire-titanium alloy welded joints in Embodiment 1 and Comparative Examples 3-6 of the present invention; Figure 3 The images show the weld morphology and EDS scan location data of the sapphire-titanium alloy welded joints in Comparative Example 2 and Example 1 of this invention. Figure 4 This is a photograph of the sapphire and metal connector welded in Comparative Example 1 of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0022] A method for soldering sapphire to metal, comprising the following steps: S1. Pretreatment: Clean and dry the sapphire and metal. The surface roughness Ra of the metal surface to be soldered is 0.5μm-1.6μm. S2. Assembly: The pre-treated sapphire and metal are stacked together, so that the solderable surface of the sapphire comes into contact with the solderable surface of the metal, and pressure is applied to it to generate interfacial pressure at the soldering interface. S3. Welding: Under an inert atmosphere, femtosecond laser welding is used to weld the areas to be welded between sapphire and metal. The welding process is as follows: Figure 1 As shown.

[0023] In existing technologies, ultrafast laser welding, with its advantages of high energy density, short pulse time, and extremely small heat-affected zone, can effectively avoid the large-scale thermal damage in traditional welding and successfully achieve the joining of sapphire and metal. However, existing femtosecond laser welding technology has extremely high requirements for material surface roughness and the contact gap between sapphire and metal (needing to achieve optical contact or nanoscale roughness). This not only reduces processing efficiency but may also lead to unstable processing quality, limiting its widespread application in industry.

[0024] To address the aforementioned problems, this invention introduces interfacial pressure-assisted femtosecond laser welding technology. By applying interfacial pressure, the shear strength of the weld joint is significantly improved, while the surface roughness requirements of the materials to be welded are reduced. This allows for welding of metals with micron-level roughness and sapphire without requiring stringent nanoscale surface treatment. It solves the problems of stringent surface roughness requirements and insufficient weld strength in existing technologies, improving not only processing efficiency but also weld quality and process stability. Furthermore, the use of inert gas protection during femtosecond laser welding prevents material oxidation, further enhancing weld quality. This method is applicable to welding various metals and sapphire, offering a wide range of applications. Joints welded using this method can be widely used in precision optical devices, semiconductor packaging, and aerospace fields.

[0025] In some embodiments, step S1 further includes sanding the metal surface to be soldered with sandpaper to obtain a suitable surface roughness. The method of the present invention is applicable to the soldering of metal materials with a surface roughness Ra of 0.5µm-1.6µm to sapphire. For example, the surface roughness of the metal surface to be soldered can be any one value or a range of any two values ​​from 0.5µm, 0.6µm, 0.8µm, 1.0µm, 1.2µm, 1.4µm, 1.6µm.

[0026] In some specific embodiments of the present invention, in step S1, the cleaning involves placing the sapphire and the metal into ethanol for ultrasonic cleaning for 10-15 minutes, with the aim of removing contaminants from the surface of the welding materials.

[0027] In some specific embodiments of the present invention, the surface roughness Ra of the sapphire surface to be soldered is 0.3μm-0.5μm. For example, it can be any single value or a range of any two values ​​among 0.3μm, 0.35μm, 0.4μm, 0.45μm, and 0.5μm. When soldering using the method of the present invention, neither the sapphire nor the metal surface to be soldered needs to be processed to a mirror finish or nanoscale roughness, which reduces the processing difficulty and processing cost, and significantly improves processing efficiency and the stability of the production process.

[0028] In some specific embodiments of the present invention, the thickness of the sapphire is 1-5mm. For example, it can be any one value or a range of any two values ​​from 1mm, 2mm, 3mm, 4mm, to 5mm. By controlling the thickness of the sapphire to 1-5mm, the laser energy can penetrate and deposit better at the interface, achieving a better welding effect.

[0029] In some specific embodiments of the present invention, sapphire can transmit light in the range of 300nm-5000nm and has a transmittance greater than 87%. When femtosecond laser welding sapphire and metal, the laser must first pass through the sapphire and finally act on the contact interface between the sapphire and the metal. If the transmittance is too low, the laser energy will be greatly lost during the process of penetrating the sapphire, resulting in insufficient energy reaching the interface and affecting the welding effect. The high transmittance of sapphire is a prerequisite for the efficient and stable arrival of femtosecond laser energy at the welding interface. This ensures that the metal side receives sufficient energy to form an effective weld and also avoids damage to the sapphire itself due to absorption or scattering of the laser, thus achieving an efficient connection between sapphire and metal.

[0030] In some specific embodiments of the present invention, the metal can be a pure metal or an alloy, preferably including at least one of titanium alloy, copper and Invar alloy.

[0031] In some specific embodiments of the present invention, in step S2, the applied pressure S0 satisfies: S-0.27≤S0≤S+0.27; in, , The unit of S is MPa, Ra 金 denoted as , where is the surface roughness of the metal surface to be welded, in μm; HV is the Vickers hardness of the metal, in MPa; E is the elastic modulus of the metal, in GPa; and α, β, and γ are material constants. The parameters in the formula are shown in Table 1 when the metal materials are titanium alloy, Invar alloy, and copper, respectively. Table 1

[0032] The pressure S calculated using the above formula is the optimal applied pressure. S and Ra 金 A positive correlation exists: the higher the surface roughness of the metal, the more microscopic protrusions there are, requiring greater interfacial pressure to induce plastic deformation and fill the gap with the sapphire. Conversely, lower roughness results in a smoother surface, requiring less pressure to achieve close contact. Controlling the applied pressure within the range of S ± 0.27 yields good welding results. For example, S0 can be any single value or a range of any two values ​​from S-0.27, S-0.23, S-0.2, S-0.1, S-0.02, S, S+0.1, S+0.2, and S+0.27. A better result is achieved when S0 is equal to or close to S.

[0033] In some specific embodiments of the present invention, the laser power of the femtosecond laser welding is 4.8W-14.0W, for example, it can be any single value or a range of any two values ​​selected from 4.8W, 5.2W, 7W, 8.1W, 10W, 12W, and 14W; the scanning speed is 10mm / s-15mm / s, for example, it can be any single value selected from 10mm / s, 11mm / s, 12mm / s, 13mm / s, 14mm / s, and 15mm / s. The range of values ​​formed by any two points; the laser pulse width is 200fs-500fs, for example, it can be any one value or a range of any two points among 200fs, 250fs, 300fs, 350fs, 400fs, 450fs, and 500fs; the laser repetition frequency is 1MHz-20MHz, for example, it can be any one value or a range of any two points among 1MHz, 5MHz, 10MHz, 15MHz, and 20MHz.

[0034] In some specific embodiments of the present invention, the laser wavelength for femtosecond laser welding is 1025nm-1035nm, for example, it can be any one value or a range of any two values ​​among 1025nm, 1028nm, 1030nm, 1032nm, and 1035nm; the laser focal position is -0.01mm to +0.01mm, for example, it can be any one value or a range of any two values ​​among -0.01mm, -0.005mm, 0mm, +0.005mm, and +0.01mm.

[0035] In some specific embodiments of the present invention, the femtosecond laser welding process controls the welding path of the laser beam through a galvanometer. The welding path is a parallel line, and the spacing between each scanning line is 50μm-100μm. For example, it can be any point value or a range of any two point values ​​among 50μm, 60μm, 70μm, 80μm, 90μm, and 100μm.

[0036] A method for welding sapphire and titanium alloy, wherein the welding is performed using any one of the aforementioned embodiments.

[0037] A welded joint is obtained by welding using any one of the aforementioned embodiments; the weld seam of the welded joint provided by the present invention has no obvious defects, the interface elements are uniformly diffused, the sapphire and the metal form a metallurgical bond, and the joint has high shear strength.

[0038] The embodiments of the present invention will be described in detail below with reference to specific examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0039] Example 1 This embodiment involves welding sapphire to a TC4 titanium alloy sheet. The sapphire has dimensions of 20×20×1mm, and the titanium alloy has dimensions of 20×40×2mm. The Vickers hardness HV=350MPa, the elastic modulus E=110GPa, and the welding area is 4mm². 2 ; S1. Pretreatment: Use 400-grit sandpaper to polish the surface of the titanium alloy to be welded, so that its surface roughness Ra=1.6µm. Use finished sapphire with a surface roughness Ra=0.5µm. Place the sapphire and titanium alloy in ethanol for ultrasonic cleaning for 12 minutes to remove surface contaminants and dry them. S2. Assembly: The pre-treated sapphire and titanium alloy are stacked one on top of the other, with the titanium alloy below the sapphire, so that the solderable surface of the sapphire is in contact with the solderable surface of the titanium alloy. According to the formula, S = (0.035 × 3.18 + 0.25) × 1.6 + 0.15 = 0.73 MPa. The stacked sapphire and titanium alloy are fixed with a clamp and a pressure of 0.75 MPa is applied to them. S3. Welding: Under an inert atmosphere, femtosecond laser welding is used to weld the areas to be welded on sapphire and titanium alloy. The laser power is 8.1W, the scanning speed is 10 mm / s, the laser focus position is +0 mm, the laser wavelength is 1030 nm, the laser repetition frequency is 10 MHz, the laser pulse width is 211 fs, and the welding scan line spacing is 50 μm.

[0040] Example 2 Example 2 is similar to Example 1, except that in step S2, the pressure applied to the stacked sapphire and titanium alloy is 0.5 MPa, and all other conditions are the same as in Example 1.

[0041] Example 3 Example 3 is similar to Example 1, except that in step S2, the pressure applied to the stacked sapphire and titanium alloy is 1 MPa, and all other conditions are the same as in Example 1.

[0042] Example 4 This embodiment involves welding sapphire to a 4J36 Invar alloy sheet. The sapphire has dimensions of 20×20×1mm, and the 4J36 Invar alloy has dimensions of 20×40×2mm. The Vickers hardness HV=200MPa, the elastic modulus E=140GPa, and the welding area is 4mm². 2 ; S1. Pretreatment: Use 400-grit sandpaper to polish the surface of the 4J36 Invar alloy to be soldered, so that its surface roughness Ra=1.6µm. Use finished sapphire with a surface roughness Ra=0.5µm. Place the sapphire and 4J36 Invar alloy in ethanol for ultrasonic cleaning for 10 minutes to remove surface contaminants, and then dry them. S2. Assembly: Place the pretreated sapphire and 4J36 Invar alloy on top of each other, with the 4J36 Invar alloy below the sapphire, so that the solderable surface of the sapphire is in contact with the solderable surface of the 4J36 Invar alloy. Calculate S = (0.028 × 1.43 + 0.20) × 1.6 + 0.20 = 0.58 MPa according to the formula. Fix the stacked sapphire and 4J36 Invar alloy with a fixture and apply a pressure of 0.58 MPa to them. S3. Welding: Under an inert atmosphere, femtosecond laser welding was used to weld the areas to be welded on sapphire and 4J36 Invar alloy. The laser power was 7.8W, the scanning speed was 10 mm / s, the laser focus position was +0 mm, the laser wavelength was 1030 nm, the laser repetition frequency was 10 MHz, the laser pulse width was 211 fs, and the welding scan line spacing was 50 μm.

[0043] Example 5 This embodiment involves welding sapphire to copper sheet. The sapphire size is 20×20×1mm, and the copper size is 20×40×2mm. The Vickers hardness HV=100MPa, the elastic modulus E=110GPa, and the welding area is 4mm². 2 ; S1. Pretreatment: Polish the copper surface to be soldered with 400-grit sandpaper to achieve a surface roughness Ra=1.6µm. Use finished sapphire with a surface roughness Ra=0.5µm. Place the sapphire and copper in ethanol for ultrasonic cleaning for 15 minutes to remove surface contaminants and then dry them. S2. Assembly: Place the pre-treated sapphire and copper on top of each other, with the copper below the sapphire, so that the solderable surfaces of the sapphire and copper are in contact. Calculate S = (0.015 × 0.9 + 0.15) × 1.6 + 0.10 = 0.36 MPa according to the formula. Fix the stacked sapphire and copper with a clamp and apply a pressure of 0.36 MPa to them. S3. Welding: Under an inert atmosphere, femtosecond laser welding is used to weld the areas to be welded on sapphire and copper. The laser power is 5.2W, the scanning speed is 10 mm / s, the laser focus position is +0 mm, the laser wavelength is 1030 nm, the laser repetition frequency is 10 MHz, the laser pulse width is 211 fs, and the welding scan line spacing is 50 μm.

[0044] Comparative Example 1 This comparative example involves welding sapphire to TC4 titanium alloy sheet. The sapphire dimensions are 20×20×1mm, and the titanium alloy dimensions are 40×40×2mm. The surface roughness of the sapphire surface to be welded is Ra0.5µm, and the surface roughness of the titanium alloy surface to be welded is Ra1.6µm. Continuous laser welding of the sapphire and titanium alloy was performed using the following parameters: laser power 1000W, welding speed 5mm / s, minimum spot radius 1mm, laser wavelength 1030nm, defocusing amount +0mm, and applied pressure load +0.25MPa.

[0045] Comparative Example 2 Comparative Example 2 is similar to Example 1, except that no pressure load is applied in step S2, and all other conditions are the same as in Example 1.

[0046] Comparative Example 3 Comparative Example 3 is similar to Example 1, except that the pressure applied in step S2 is 0.125 MPa, and all other conditions are the same as in Example 1.

[0047] Comparative Example 4 Comparative Example 4 is similar to Example 1, except that the pressure applied in step S2 is 0.25 MPa, and all other conditions are the same as in Example 1.

[0048] Comparative Example 5 Comparative Example 5 is similar to Example 1, except that the pressure applied in step S2 is 1.25 MPa, and all other conditions are the same as in Example 1.

[0049] Comparative Example 6 Comparative Example 6 is similar to Example 1, except that the pressure applied in step S2 is 1.75 MPa, and all other conditions are the same as in Example 1.

[0050] Comparative Example 7 Comparative Example 7 is similar to Example 1, except that the pressure applied in step S2 is 2.25 MPa, and all other conditions are the same as in Example 1.

[0051] Test case The shear strength of the welded joints obtained in each embodiment and comparative examples 2-7 was tested using a universal testing machine. The test was conducted according to GB / T 11363-2008, and the test results are shown in Table 2.

[0052] Table 2

[0053] As shown in Table 1, applying appropriate interfacial pressure during femtosecond laser welding enables the welding of sapphire with metal materials having surface roughness in the micrometer range, and the resulting joints exhibit high shear strength. When the surface roughness Ra of sapphire is 0.5µm and the surface roughness Ra of the metal is 1.6µm, the shear strengths of the welded joints of sapphire with 4J36 Invar alloy, copper, and titanium alloy can reach 120.0MPa, 122.5MPa, and 32.0MPa, respectively. This ensures welding quality while reducing polishing costs and improving production efficiency. Compared with Comparative Example 2, applying pressure significantly increases the shear strength of the weld. As the load increases, the shear strength of the weld first increases and then decreases. When the applied interfacial pressure is too high, the fixed gap becomes too small, causing severe cracking of the sapphire base material. Therefore, precise control of the interfacial pressure between the weldment components is necessary to achieve better welding quality.

[0054] Figure 2The surface morphology of the sapphire and titanium alloy welded joints in Embodiment 1 and Comparative Examples 3-6 of the present invention is shown in (a) as the weld morphology, (b) as an enlarged view of region A, (c) as an enlarged view of region B, and (d) as an enlarged view of region C. Figure 2 It can be seen that when the applied interfacial pressure is appropriate, the weld is defect-free and the welding effect is good; when the applied interfacial pressure is too low (0.125MPa, 0.25MPa), complete welding cannot be achieved; when the applied pressure is too high (1.25MPa, 1.75MPa), cracks appear in the sapphire base material.

[0055] Figure 3 The figures show the weld morphology and EDS scan position data of the sapphire and titanium alloy welded joints in Comparative Example 2 and Example 1. (a) is the weld morphology of Comparative Example 2, (b) is the EDS scan position data of Comparative Example 2, (c) is the weld morphology of Example 1, and (d) is the EDS scan position data of Example 1. Figure 3 It can be seen that when no interfacial pressure is applied, the sapphire and titanium alloy fail to bond tightly, with a significant gap at the interface. Numerous cracks form at the weld / base material interface, and O, Al, Ti, and V elements diffuse only at the interface. The sapphire and titanium alloy fail to form a metallurgical bond. When the interfacial pressure is 0.75 MPa, there is no gap between the sapphire and the titanium alloy base material, no cracks at the weld / base material interface, a uniform transition at the sapphire-titanium alloy connection without cracks, no significant fluctuations in elemental signals, and uniform element diffusion at the interface. The sapphire and titanium alloy can form a metallurgical bond.

[0056] Figure 4 The image shows a photograph of the sapphire and metal joint soldered using the method in Example 1, such as... Figure 4 As shown, after high-power continuous laser scanning, obvious ablation marks appeared on the surface of the titanium alloy, and the sapphire was completely broken, failing to achieve an effective connection between the sapphire and the titanium alloy. This indicates that continuous laser welding is not suitable for high-quality connection between sapphire and metal.

[0057] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for welding sapphire to metal, characterized in that, Includes the following steps: S1. Pretreatment: cleaning and drying the sapphire and metal, wherein the surface roughness Ra of the metal to be soldered is 0.5μm-1.6μm; S2. Assembly: The pretreated sapphire and the metal are stacked together, so that the solderable surface of the sapphire comes into contact with the solderable surface of the metal, and pressure is applied to them to generate interfacial pressure at the soldering interface. S3. Welding: Under an inert atmosphere, femtosecond laser welding is used to weld the areas to be welded of the sapphire and the metal.

2. The welding method between sapphire and metal according to claim 1, characterized in that, The surface roughness Ra of the sapphire surface to be soldered is 0.3μm-0.5μm.

3. The welding method between sapphire and metal according to claim 1, characterized in that, The thickness of the sapphire is 1-5mm.

4. The welding method between sapphire and metal according to claim 1, characterized in that, The sapphire can transmit light in the 300nm-5000nm range, with a transmittance greater than 87%.

5. The welding method between sapphire and metal according to claim 1, characterized in that, The metal includes at least one of titanium alloys, copper, and Invar alloys.

6. The welding method between sapphire and metal according to claim 1, characterized in that, In step S2, the applied pressure S0 satisfies: S-0.27≤S0≤S+0.27; in, , The unit of S is MPa, Ra 金 α is the surface roughness of the metal to be welded, in μm; HV is the Vickers hardness of the metal, in MPa; E is the elastic modulus of the metal, in GPa; α, β, and γ are material constants: when the metal is a titanium alloy, α = 0.035, β = 0.25, γ = 0.15; when the metal is an Invar alloy, α = 0.028, β = 0.20, γ = 0.20; when the metal is copper, α = 0.015, β = 0.15, γ = 0.

10.

7. The welding method for sapphire and metal according to claim 1, characterized in that, The femtosecond laser welding uses a laser power of 4.8W-14.0W, a scanning speed of 10mm / s-15mm / s, a laser pulse width of 200fs-500fs, and a laser repetition frequency of 1MHz-20MHz.

8. The method for welding sapphire to metal according to claim 1, characterized in that, The laser wavelength for the femtosecond laser welding is 1025nm-1035nm, and the laser focal position is -0.01mm to +0.01mm.

9. The welding method for sapphire and metal according to claim 1, characterized in that, The scanning line spacing of the femtosecond laser welding is 50μm-100μm.

10. A welded joint, characterized in that, It is obtained by welding using the welding method described in any one of claims 1-9.

Images