SiC particle reinforced aluminum matrix composite laser welding performance optimization method

Abstract

The invention relates to the technical field of composite material laser welding, in particular to a SiC particle reinforced aluminum-based composite material laser welding performance optimization method which comprises the steps that a SiCp / A1-based composite material welding seam is obtained through a laser welding system under inert gas protection; in the welding process, powder for inhibiting interface reaction is added to the front portion of a laser beam, SiC powder is added to the rear portion of the laser beam, and SiC particles are introduced in the weld metal solidification process; swing laser is introduced to stir a molten pool, a high-speed electromagnetic valve type spray head is used for controlling on-off of SiC powder carrying airflow to achieve pulse type spraying powder adding, and the SiC powder airflow is introduced into a low-temperature area on the rear portion of the molten pool within the 1 / 2 period, located at the front edge of the molten pool, of the swing laser beam. According to the method, the interface reaction between the SiC particles and the Al matrix can be effectively inhibited, and the enhancement effect of the SiC powder on the mechanical property of the welding seam is improved.

Description

Technical Field

[0001] This application relates to the field of laser welding technology for composite materials, and in particular to a method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composite materials. Background Technology

[0002] SiC particle-reinforced aluminum matrix composites (SiC p A1-based composites (SiC composites) are widely used in aerospace, automotive, and shipbuilding industries due to their high specific strength, specific stiffness, specific modulus, and excellent corrosion resistance and high-temperature resistance. However, the significant differences in melting point, hardness, and other physicochemical properties between the SiC particle reinforcing phase and the aluminum alloy matrix, with the SiC particle melting point being much higher than that of the aluminum alloy matrix, make it difficult for the reinforcing phase to melt during fusion welding. This results in high molten pool viscosity and poor fluidity, preventing the timely escape of pores generated during the rapid solidification process of laser welding, leading to poor weld formation quality. Furthermore, during fusion welding, the aluminum alloy matrix and SiC particle reinforcing phase are prone to interfacial chemical reactions when the melting temperature exceeds 770℃, generating needle-like brittle Al4C3 phases. This further reduces the fluidity of the molten pool, preventing pores from escaping and affecting weld formation quality. On the other hand, the formation of brittle phases disrupts the bond between the reinforcing phase and the matrix, severely reducing the mechanical properties of the welded joint. The existence of these factors makes SiC... p / A1-based composites have poor weldability, making it difficult to obtain high-quality welded joints.

[0003] Currently, for SiC p Research on welding of Al-based composites includes two methods: fusion welding and solid-state welding. Fusion welding mainly focuses on laser welding, while solid-state welding mainly focuses on friction stir welding. Friction stir welding has advantages such as lower welding temperature and smaller heat-affected zone, and it is less likely to form the brittle Al4C3 phase in SiC. p / A1-based composites have unique advantages in welding, but due to the high hardness of SiC particles, they are prone to causing severe wear on the stirring head, resulting in inconsistent weld quality over long distances. Therefore, it is difficult to achieve long-distance SiC welds. p Friction stir welding of A1-based composite materials.

[0004] Laser welding, with its advantages of high processing flexibility, high adaptability, and no limitation on part size, is widely used in SiC. p / A1-based composites have broad application prospects in the field of bonding. However, in SiC... p The formation of porosity and brittle phases during laser welding of Al-based composite materials is a major factor affecting weld formation quality and mechanical properties, thus limiting the application of laser welding technology in SiC. p Applications of A1-based composite bonding.

[0005] For SiC p / A1-based composites are prone to porosity during laser welding. To mitigate this, methods such as using high power and high welding speed instead of low power and low welding speed, introducing shielding gas on the back side to prevent gas from entering the molten pool, and pre-welding treatment to remove the oxide film are employed. While these measures can reduce the number of pores in the weld to some extent, they cannot completely eliminate porosity in the joint, thus failing to achieve high-quality SiC. p / A1-based composite laser welding joint.

[0006] For SiC p In laser welding of Al-based composites, interfacial reactions easily occur, generating the brittle Al4C3 phase. Researchers have addressed this issue by controlling the welding heat input and by pre- or in-situ introducing Ti and Zr elements during the welding process to suppress or eliminate these interfacial reactants. These measures effectively eliminate the brittle phase in the weld and improve the weld quality to some extent. p Mechanical properties of laser-welded joints in SiC-based composites. However, in particle-reinforced metal matrix composite welds, the more uniform the distribution of the reinforcing phase, the better the weld performance. While suppressing or eliminating brittle phases can reduce the loss of reinforcing phase particles, it still cannot avoid the problems of decreased reinforcing phase density and local segregation during welding, thus preventing further improvement in weld strength. Therefore, in SiC... p How to ensure complete escape of pores in the molten pool during the welding process of SiC-based composites, and how to control the density and distribution of the reinforcing phase, are crucial for optimizing SiC. p The mechanical properties of A1-based composite welds are of paramount importance. Summary of the Invention

[0007] This application provides a method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites to solve the problems mentioned in the background art.

[0008] The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites includes: SiC is obtained using a laser welding system under inert gas protection. p / A1-based composite weld seam; During the welding process, powder to suppress interfacial reactions is added to the front of the laser beam, and SiC powder is added to the rear of the laser beam, thus introducing SiC particles during the solidification of the weld metal. A oscillating laser is introduced to stir the molten pool. A high-speed electromagnetic valve nozzle is used to control the flow of SiC powder to achieve pulsed powder injection. During the half-cycle of the oscillating laser beam at the front of the molten pool, SiC powder is introduced into the low-temperature region at the rear of the molten pool.

[0009] Furthermore, it also includes: For SiCp / A1-based composite material undergoes pre-welding surface cleaning, which includes mechanical cleaning, chemical cleaning, and laser cleaning to remove oxide film and oil stains from the test plate surface; The laser cleaning process parameters include: pulsed laser power of 200W-300W, scanning speed of 2000mm / s-4000mm / s, and pulse frequency of 2kHz-4kHz.

[0010] Furthermore, it also includes: According to SiC p The characteristics of interfacial reaction in A1-based composites and the content of SiC particles are used to design filler components, addition methods, filler quantities, and the amount of weld reinforcement phase added to suppress interfacial reactions.

[0011] Furthermore, it also includes: Establishing oscillating laser welding parameters and SiC p The correlation between the porosity of weld seams in A1-based composites was investigated to determine the optimal oscillating laser welding process window.

[0012] Furthermore, the oscillating laser welding parameters include laser welding process parameters and laser oscillation parameters; The laser welding process parameters include welding plane angle θ, laser processing head deflection angle δ, laser offset y, laser power P, and welding speed v; the laser oscillation parameters include scanning mode, scanning frequency F, and scanning amplitude A. The welding plane angle θ is 20°-70°, the laser processing head deflection angle δ is 0°~15°, the laser offset y is -1mm~3mm, the laser power P is 2000W~4000W, and the welding speed v is 1m / min~4m / min; The scanning modes include clockwise circle, counterclockwise circle, and number 8; the scanning frequency F is 100Hz~300Hz, and the scanning amplitude A is 1mm~3mm.

[0013] Furthermore, the weld porosity is the ratio of the pore area of ​​the weld longitudinal section to the total cross-sectional area.

[0014] Furthermore, it also includes: When fillers that suppress interfacial reactions are added in situ, a powder feeder / wire feeder is added to the front end of the laser head so that the powder feeder / wire feeder intersects with the laser beam at one point, and welding and pre-filling are carried out simultaneously during the welding process.

[0015] Furthermore, it also includes: A high-speed solenoid valve nozzle is added after the laser head to achieve pulsed addition of SiC particles. The powder feeding direction of the nozzle is parallel to the laser beam, and the on / off frequency of the high-speed solenoid valve nozzle is consistent with the scanning frequency of the oscillating laser beam. By controlling the frequency of the solenoid valve's switching, the temperature range at which SiC particles are added to the molten pool can be selected. By adding SiC particles in the low-temperature zone at the rear of the molten pool, the interfacial reaction between SiC particles and the Al matrix can be suppressed.

[0016] Furthermore, it also includes: If pre-filled material is selected, pre-filled foil is placed in the butt joint of the SiCp / Al-based composite material before welding, and SiC powder is added to the powder feeder; if in-situ addition is selected, different types of powder are placed in the dual-cylinder powder feeder before welding.

[0017] Furthermore, the inert gas includes argon and helium, with a flow rate of 5 L / min to 25 L / min.

[0018] The above-mentioned technical solution of this application has the following advantages: The laser welding performance optimization method for SiC particle-reinforced aluminum matrix composites provided in this application optimizes the laser welding performance of SiC particle-reinforced aluminum matrix composites by... p In the laser welding process of Al-based composites, powder that inhibits interfacial reactions is added to the front of the laser beam to eliminate brittle needle-like Al4C3 phases and pores, improve the fluidity of the molten pool, and enhance the weld formation quality. By adding SiC powder to the rear of the laser beam, SiC particles are introduced during weld metal solidification, increasing the density of the reinforcing phase in the weld and optimizing the mechanical properties of the SiCp / Al-based composite weld. The introduction of a oscillating laser stirs the molten pool, increasing its fluidity, accelerating the removal of pores, inhibiting SiC particle segregation, and promoting the homogenization of the reinforcing phase, further optimizing the joint's mechanical properties. Pulsed jet powder addition is achieved by controlling the flow of SiC powder using a high-speed electromagnetic valve nozzle. During the first half of the oscillating laser beam's cycle at the molten pool's leading edge, SiC powder is introduced into the low-temperature region at the rear of the molten pool, effectively suppressing the interfacial reaction between SiC particles and the Al matrix and enhancing the reinforcing effect of SiC powder on the weld's mechanical properties. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of this application or 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 this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1A schematic diagram of a laser welding system provided in an embodiment of this application; Figure 2 The SiC provided in the embodiments of this application p / 2A14 Aluminum-based composite laser-welded joint morphology: (ab) Direct laser welding technology; (cd) Laser welding using the scheme of this application.

[0021] Figure reference numerals: 1-Working platform; 2-Aluminum composite test plate; 3-Weld seam; 4-Powder feeding hose; 5-Powder feeding nozzle; 6-Laser processing head deflection angle δ; 7-Oscillating laser beam; 8-Laser; 9-High-speed solenoid valve type nozzle; 10-Welding direction; 11-Double-cylinder powder feeder; 12-Zr powder; 13-SiC powder. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0023] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0024] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means "two or more."

[0026] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0027] This application provides a method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites, including the following steps: S100: For SiC p / A1-based composite material undergoes surface cleaning before welding.

[0028] S200: Based on SiC p The characteristics of interfacial reaction in A1-based composites and the content of SiC particles are used to design filler components, addition methods, filler quantities, and the amount of weld reinforcement phase added to suppress interfacial reactions.

[0029] S300: Establishing Oscillating Laser Welding Parameters and SiC p The correlation between the porosity of weld seams in A1-based composites was investigated to determine the optimal oscillating laser welding process window.

[0030] S400: SiC obtained using a laser welding system under inert gas protection. p / A1-based composite weld.

[0031] S500: Quality Inspection. Non-destructive testing (NDT) is performed on welded joints, including X-ray inspection and penetrant testing.

[0032] In step S100, surface cleaning includes mechanical cleaning, chemical cleaning and laser cleaning to remove oxide film and oil stains and other impurities from the surface of the test plate. The cleaning area is only within 5mm-10mm of the welding area.

[0033] In step S100, the process parameters for laser cleaning mainly include pulsed laser power P, scanning speed v, and pulse frequency f. The pulsed laser power P is selected in the range of 200W-300W, the scanning speed is 2000mm / s-4000mm / s, and the pulse frequency is 2kHz-4kHz.

[0034] In step S200, SiC p In Al-based composites, the Al matrix and SiC particle reinforcement phase are prone to interfacial reactions as shown in (1) when the temperature exceeds 770℃: 4Al(l) + 3SiC(s) —>Al4C3(s) + 3Si(s)(1) To suppress interfacial reactions, two approaches can be taken. First, based on the relative free energies of different carbides at high temperatures (Al4C3 > TiC > ZrC), adding Ti and Zr elements during welding can induce in-situ reactions, reducing the formation of the brittle Al4C3 phase. Simultaneously, TiC and ZrC particles can be generated as reinforcing phases, enhancing the mechanical properties of the joint. Second, adding Si elements during welding increases the Si activity in the molten pool, significantly raising the interfacial reaction free energy ΔG and reducing the tendency for interfacial reactions to occur. Therefore, the filler composition for suppressing interfacial reactions consists of Ti, Zr, and Si elements, which can be used individually or in combination.

[0035] In step S200, the methods for adding fillers to the welding process to suppress interfacial reactions can be divided into two main categories. One is the pre-filled type, where fillers are added to the weld in the form of foil, powder, etc., before the laser welding process begins. This type of filler requires simple and easy-to-operate experimental equipment and is suitable for pre-experimentation on small-sized test plates. The other is the in-situ addition type, where fillers are introduced into the molten pool simultaneously in the form of wire, powder, etc., during the welding process. This type of filler requires complex experimental equipment but allows for precise control of the welding process and a high level of automation, making it suitable for large-sized welding processes. Furthermore, for both filler types, the combined fillers are mixed before being added.

[0036] In step S200, the amount of filler introduced into the molten pool directly affects the SiC content. p The final state of the Al-based composite weld requires careful selection of filler quantity based on the characteristics of the interfacial reaction and the SiC particle content. This is to control the formation of Al3M intermetallic compounds and MC phases, thereby regulating the proportion of different phases and microstructures in the joint and optimizing its microstructure and mechanical properties. For fillers that inhibit interfacial reactions, the appropriate filler quantity must be selected based on the SiC content. p The SiC particle content in Al-based composites is adjusted by introducing elemental content into the molten pool. For example, regarding Ti, insufficient Ti introduction during welding will still result in the formation of the brittle Al4C3 phase through interfacial reactions, deteriorating the joint's mechanical properties. Conversely, excessive Ti introduction prevents sufficient diffusion within the molten pool, leading to the reaction of excess Ti with Al to form Al3Ti. This excessively grown Al3Ti, appearing as flakes, negatively impacts the joint's mechanical properties. The amount of filler can be adjusted by controlling the thickness of the pre-placed foil (powder layer) and the rate of synchronous powder (wire) feeding.

[0037] In step S200, the amount of SiC particles added needs to be properly controlled. Too little addition will only effectively optimize the mechanical properties of the joint; too much addition will severely affect the fluidity of the molten alloy and deteriorate the weld formation quality. The amount of filler can be controlled by adjusting the synchronous powder feeding rate.

[0038] In step S300, the process parameters for oscillating laser welding include laser welding process parameters (welding plane angle θ, laser processing head deflection angle δ, laser offset y, laser power P, welding speed v) and laser oscillation parameters (scanning mode, scanning frequency F, scanning amplitude A). The selection range for the welding plane angle θ is 20°-70°, the laser processing head deflection angle δ is 0°~15°, the laser offset y is -1mm~3mm, the laser power P is 2000W~4000W, and the welding speed v is 1m / min~4m / min. The oscillating laser scanning modes include three types: clockwise circle, counterclockwise circle, and digital 8; the selection range for the scanning frequency is 100Hz~300Hz, and the scanning amplitude is 1mm~3mm.

[0039] In step S300, the weld porosity ω is the pore area S of the weld longitudinal section. p The ratio to the total cross-sectional area S, that is: In step S400, when the filler for inhibiting interfacial reaction is added in situ, a powder feeder / wire feeder can be added to the front end of the laser head so that the powder feeder / wire feeder intersects with the laser beam at one point. Welding and pre-filling are carried out simultaneously during the welding process to ensure that the filler can fully enter the molten pool.

[0040] In step S400, a high-speed solenoid valve nozzle is added after the laser head to achieve pulsed addition of SiC particles. The powder feeding direction of the nozzle is parallel to the laser beam, and the on / off frequency of the high-speed solenoid valve nozzle is consistent with the scanning frequency of the oscillating laser beam. By controlling the switching frequency of the solenoid valve, the temperature range in which SiC particles are added to the molten pool is selected. Adding SiC particles in the low-temperature zone at the rear of the molten pool suppresses the interfacial reaction between SiC particles and the Al matrix, thereby improving the strengthening effect of SiC powder on the mechanical properties of the weld.

[0041] In step S400, if pre-filling is selected, pre-filled foil needs to be placed in the butt joint of the SiCp / Al-based composite material before welding, and SiC powder needs to be added to the powder feeder; if in-situ addition is selected, different types of powder need to be added to the dual-cylinder powder feeder before welding.

[0042] In step S400, the protective gas includes argon and helium, and the flow rate of the protective gas is generally selected as 5L / min-25L / min. The protective gas can be applied coaxially with the laser beam or off-axis.

[0043] In SiC p In the circular beam oscillating laser welding process of Al-based composite materials, a high-speed electromagnetic valve nozzle is used to spray SiC powder into the low-temperature zone at the rear of the molten pool during half a cycle when the oscillating laser beam is at the leading edge of the molten pool. This increases the density of the reinforcing phase in the weld and effectively suppresses the interfacial reaction between SiC particles and the Al matrix, thereby improving the reinforcing effect of SiC powder on the mechanical properties of the weld.

[0044] By introducing a oscillating laser and adjusting its process parameters, the molten pool is stirred. This reduces the deteriorating effect of SiC particles in the base metal on the molten pool viscosity, improves molten pool fluidity, promotes the removal of porosity, and enhances weld formation quality. Furthermore, it suppresses SiC particle segregation in the weld fusion zone, promoting uniform distribution of SiC particles within the weld and mitigating the deteriorating effect of SiC particle segregation on the joint's mechanical properties. Moreover, when the oscillating laser beam is located at the latter half of its cycle in the molten pool, the stirring effect further promotes the uniform distribution of additional SiC particles within the weld, further optimizing the joint's mechanical properties.

[0045] Through SiC p Adding fillers to inhibit interfacial reactions during laser welding of Al-based composites can suppress the consumption of SiC particles by interfacial reactions, inhibit the formation of acicular brittle phases, reduce or eliminate their deteriorating effects on molten pool fluidity and weld mechanical properties, promote porosity overflow, and improve weld formation quality. Filler methods can be divided into pre-placed filler type and in-situ addition type, and filler components can be divided into single-component and mixed-component types.

[0046] The following is a detailed description through specific embodiments. This technical solution specifically implements a SiC particle-reinforced 2A14 aluminum matrix composite material (SiC...). p Laser welding of / 2A14 aluminum-based composite material, wherein the volume percentage of SiC particles is 15%, the average particle size is 20μm, the length of the test plate is 70mm, the width is 20mm, and the thickness is 2mm.

[0047] Example 1: S100: Laser cleaning is used for SiC p / 2A14 aluminum-based composite material underwent pre-welding surface cleaning to remove oxide film, oil, and other impurities from the test plate surface. Laser cleaning parameters: pulsed laser power P = 300W, scanning speed = 2500mm / s, pulse frequency = 3kHz.

[0048] S200: Based on SiCp The characteristics of interfacial reactions in A1-based composites and the selection of SiC particle content in SiC p Before laser welding of / 2A14 aluminum-based composites, a 0.05mm thick Ti foil is pre-placed in the weld seam to suppress interfacial reactions. SiC particles are then sprayed into the molten pool through a high-speed solenoid valve nozzle at a feed rate of 8g / min. The average particle size of the SiC particles is 20μm.

[0049] S300: Establishing Oscillating Laser Welding Parameters and SiC p The correlation between the porosity ω of the weld seam in / 2A14 aluminum-based composite was investigated to determine the optimal oscillating laser welding process window, wherein the welding plane angle θ is 45°, the laser processing head deflection angle δ is 10°, the laser offset y is 1mm, the laser power P is 2000W, the welding speed is 1.8m / min, the oscillating laser scanning mode is clockwise circle, the scanning frequency selection range is 100Hz, and the scanning amplitude is 1mm.

[0050] S400: Employing a method such as... under inert gas protection. Figure 1 The laser welding system shown obtains SiC p / 2A14 aluminum-based composite weld. When the oscillating laser beam is at the starting point of 1 / 2 cycle of the molten pool front, the high-speed solenoid valve is opened, and SiC powder is injected into the low-temperature zone at the rear of the molten pool using a nozzle. The on / off frequency of the high-speed solenoid valve nozzle is consistent with the scanning frequency of the oscillating welding, and the powder feeding direction of the nozzle is parallel to the laser beam. Real-time protection of the laser welding process is achieved using coaxial argon gas supply, with a shielding gas flow rate of 15 L / min.

[0051] S500: Quality inspection. For SiC p X-ray non-destructive testing was performed on the welded joint of the / 2A14 aluminum-based composite material.

[0052] The SiC obtained in this embodiment p / 2A14 aluminum-based composite laser welding produces a well-formed weld surface, and welding defects such as cracks and porosity are effectively controlled. Compared with welds obtained by directly using laser welding technology, the porosity is significantly reduced, meeting the requirements of Class I aerospace standard welds, and the Al4C3 brittle phase in the weld is basically eliminated.

[0053] Example 2: This example is illustrated with diagrams. S100: Laser cleaning is used for SiC p / 2A14 aluminum-based composite material 2 undergoes pre-welding surface cleaning to remove oxide film, oil, and other impurities from the test plate surface. Laser cleaning parameters: pulsed laser power P = 300W, scanning speed = 2500mm / s, pulse frequency = 3kHz.

[0054] S200: Based on SiCp The characteristics of the interface reaction of A1-based composites and the selection of SiC particle content: During the welding process, Zr powder is introduced into the molten pool at the front edge of the molten pool using a bypass feeding method. The feeding speed is 16 g / min and the average particle size of Zr powder is 75 μm. SiC particles are sprayed into the molten pool through a high-speed solenoid valve nozzle. The feeding speed is 8 g / min and the average particle size of SiC particles is 20 μm.

[0055] S300: Establishing Oscillating Laser Welding Parameters and SiC p The correlation between the porosity ω of the weld seam in / 2A14 aluminum-based composite was investigated to determine the optimal oscillating laser welding process window, in which the welding plane angle θ was 45°, the laser processing head deflection angle δ was 10°, the laser offset y was 1mm, the laser power P was 2000W, the welding speed was 1.8m / min, the oscillating laser scanning mode was digital 8, the scanning frequency selection range was 150Hz, and the scanning amplitude was 1mm.

[0056] S400: Employing a method such as... under inert gas protection. Figure 1 The laser welding system shown obtains SiC p / 2A14 aluminum-based composite weld seam 3. Real-time protection of the laser welding process is achieved using coaxial argon gas supply at a flow rate of 15 L / min. Zr powder 12 is introduced into the molten pool via off-axis feeding. When the oscillating laser beam is at the beginning of half a cycle of the molten pool's leading edge, the high-speed solenoid valve is opened, and SiC powder 13 is injected into the low-temperature zone at the rear of the molten pool using nozzle 9. The on / off frequency of the high-speed solenoid valve nozzle is consistent with the scanning frequency of the oscillating welding head 7, and the powder feeding direction of the nozzle is parallel to the laser beam.

[0057] S500: Quality inspection. For SiC p X-ray non-destructive testing was performed on the welded joint of the / 2A14 aluminum-based composite material.

[0058] Combination Figure 2 SiC under different technical conditions p The cross-sectional morphology results of the laser welding of / 2A14 aluminum-based composites show that the SiC obtained using this technical solution is... p The surface finish of the laser-welded / 2A14 aluminum-based composite is excellent, and welding defects such as cracks and porosity are effectively controlled. Compared with welds obtained directly using laser welding technology, the porosity is significantly reduced, meeting the requirements of Class I aerospace standard welds. Furthermore, the brittle Al4C3 phase in the weld is essentially eliminated, and the TiC reinforcing phase generated by the interface reaction and the added SiC particles are evenly distributed. The tensile strength of the joint can reach that of SiC. p The tensile strength of the 2A14 aluminum-based composite matrix is ​​more than 50% (>260 MPa) of the base material (486 MPa), compared to SiC obtained directly by laser welding.p The / 2A14 aluminum-based composite joint has a tensile strength increased by more than 100MPa, with a growth rate of over 70%, and the mechanical properties of the joint are significantly improved.

[0059] In summary, the proposed solution is reasonable and feasible, and is particularly suitable for the laser welding process of SiC particle-reinforced 2xxx and 6xxx series aluminum matrix composites.

[0060] It should be clarified that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. This application is not limited to the specific structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0061] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for optimizing laser welding properties of SiC particulate reinforced aluminum matrix composites, characterized in that, include: SiC p / A1 matrix composite weld During the welding process, powder to suppress interfacial reactions is added to the front of the laser beam, and SiC powder is added to the rear of the laser beam, thus introducing SiC particles during the solidification of the weld metal. A oscillating laser is introduced to stir the molten pool. A high-speed electromagnetic valve nozzle is used to control the flow of SiC powder to achieve pulsed powder injection. During the half-cycle of the oscillating laser beam at the front of the molten pool, SiC powder is introduced into the low-temperature region at the rear of the molten pool.

2. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: SiC p Pre-weld surface cleaning of SiC p / A1 matrix composites, including mechanical cleaning, chemical cleaning and laser cleaning, to remove surface oxide film and oil stains The laser cleaning process parameters include: pulsed laser power of 200W-300W, scanning speed of 2000mm / s-4000mm / s, and pulse frequency of 2kHz-4kHz.

3. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: According to SiC p Characteristics of SiC / A1 interfacial reactions and the content of SiC particles were designed to inhibit interfacial reactions by filler components, addition methods, filler amounts, and supplemental amounts of weld reinforcement phases.

4. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: Establishing the correlation between the parameters of the oscillating laser welding and the porosity of the SiC p / A1 matrix composite welds, confirming the optimal oscillating laser welding process window.

5. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 4, characterized in that, The oscillating laser welding parameters include laser welding process parameters and laser oscillation parameters; The laser welding process parameters include welding plane angle θ, laser processing head deflection angle δ, laser offset y, laser power P, and welding speed v; the laser oscillation parameters include scanning mode, scanning frequency F, and scanning amplitude A. The welding plane angle θ is 20°-70°, the laser processing head deflection angle δ is 0°~15°, the laser offset y is -1mm~3mm, the laser power P is 2000W~4000W, and the welding speed v is 1m / min~4m / min; The scanning modes include clockwise circle, counterclockwise circle, and number 8; the scanning frequency F is 100Hz~300Hz, and the scanning amplitude A is 1mm~3mm.

6. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 4, characterized in that, The weld porosity is the ratio of the pore area of ​​the longitudinal section of the weld to the total area of ​​the section.

7. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: When fillers that suppress interfacial reactions are added in situ, a powder feeder / wire feeder is added to the front end of the laser head so that the powder feeder / wire feeder intersects with the laser beam at one point, and welding and pre-filling are carried out simultaneously during the welding process.

8. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: A high-speed solenoid valve nozzle is added after the laser head to achieve pulsed addition of SiC particles. The powder feeding direction of the nozzle is parallel to the laser beam, and the on / off frequency of the high-speed solenoid valve nozzle is consistent with the scanning frequency of the oscillating laser beam. By controlling the frequency of the solenoid valve's switching, the temperature range at which SiC particles are added to the molten pool can be selected. By adding SiC particles in the low-temperature zone at the rear of the molten pool, the interfacial reaction between SiC particles and the Al matrix can be suppressed.

9. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, Also includes: If pre-filled material is selected, pre-filled foil is placed in the butt joint of the SiCp / Al-based composite material before welding, and SiC powder is added to the powder feeder; if in-situ addition is selected, different types of powder are placed in the dual-cylinder powder feeder before welding.

10. The method for optimizing the laser welding performance of SiC particle-reinforced aluminum matrix composites as described in claim 1, characterized in that, The inert gas includes argon and helium, with a flow rate of 5 L / min to 25 L / min.

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