A method for homogenizing reinforcing phases of an aluminum-based composite material by ultrasonic vibration assisted laser welding

Abstract

The application discloses a method for homogenizing reinforced phases of aluminum matrix composite in plug-in ultrasonic vibration assisted laser welding, and is characterized by comprising the following steps: mechanically assembling and laser spot welding fixing the workpieces to be welded; performing formal welding operation on the workpieces to be welded, and inserting an ultrasonic vibration variable amplitude tungsten needle into a molten pool to stir when a keyhole is formed, and completing welding. The variable amplitude tungsten needle is used to directly act on the laser welding molten pool by ultrasonic vibration, and the aggregation of reinforced phases in the welding process is effectively improved. Compared with the traditional method of only optimizing welding parameters or adding filler materials, the application can realize the highly uniform distribution of reinforced phases in the welded joint area, improve the weld profile morphology, and significantly improve the weld quality.

Description

Technical Field

[0001] This invention belongs to the field of materials processing engineering technology, and specifically relates to a method for homogenizing the reinforcing phase of aluminum matrix composites by insert-type ultrasonic vibration-assisted laser welding. Background Technology

[0002] With the widespread application of aluminum matrix composites (Al-MMCs) in aerospace, automotive, and high-performance structural materials, improving the quality of their welded joints has become a key research focus. Reinforcing phases in Al-MMCs typically include SiC, BC, TiC, and CNTs, which significantly enhance the material's strength, heat resistance, and wear resistance. However, during laser welding, these reinforcing phases often aggregate or unevenly distribute in the welding area, leading to unstable weld joint performance and susceptibility to defects such as cracks and porosity, severely limiting their application in high-performance environments.

[0003] In laser joining of Al-MMCs structural components, methods such as optimizing laser welding modes, welding parameters, or in-situ fillers are commonly used to suppress the reaction of the reinforcing phase and adjust its non-uniform distribution. While these methods improve joint performance to some extent, they cannot completely homogenize the distribution of reinforcing phase particles and may even lead to segregation of alloying elements in the weld joint area, resulting in a sharp decline in joint performance. Furthermore, the difficulty in controlling heat input and material flowability during the welding process further increases the complexity of reinforcing phase homogenization. Although existing technologies have made some improvements through optimizing welding parameters and adding filler materials, they have not yet completely solved the problem of reinforcing phase homogenization. Summary of the Invention

[0004] To address the problem of incomplete homogenization of reinforcing phase particle distribution in aluminum-based composite materials in existing technologies, the present invention aims to provide a method for homogenizing the reinforcing phase in aluminum-based composite materials by inserting ultrasonic vibration-assisted laser welding. This method introduces ultrasonic vibration during the laser welding process of the workpiece to be welded, and the amplitude-modulated tungsten needle of the ultrasonic vibration system is directly inserted into the molten pool for stirring. It moves synchronously with the laser to obtain a welded joint of the workpiece to be welded with good shape, uniform distribution of reinforcing phase, and excellent joint mechanical properties.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for homogenizing the reinforcing phase of aluminum-based composites by insert-type ultrasonic vibration-assisted laser welding includes the following steps:

[0007] Mechanical assembly and laser spot welding are performed on the workpieces to be welded.

[0008] When performing the formal welding operation on the workpiece to be welded, a variable amplitude tungsten needle capable of ultrasonic vibration is inserted into the molten pool to stir the weld when the keyhole is formed, thus completing the welding.

[0009] Furthermore, the mechanical assembly and laser spot welding of the workpiece to be welded includes the following steps: the workpiece to be welded is mechanically assembled using copper pads, wherein the copper pads consist of two pairs of upper and lower copper pads with a groove on the lower pad, the workpiece to be welded is positioned, and then the two ends are fixed by laser spot welding.

[0010] Furthermore, the workpiece to be welded is an aluminum-based composite material reinforced with silicon carbide particles.

[0011] Furthermore, the size of the workpiece to be welded is 5~40μm, and the volume fraction of the silicon carbide particle reinforcement phase is 5~25%.

[0012] Furthermore, the process parameters for laser spot welding are as follows:

[0013] Laser power: 800W~1500W;

[0014] Welding speed: 0.5m / min~1.0m / min;

[0015] Defocusing amount: -3mm to 3mm;

[0016] Protective gas: 99.99% Ar;

[0017] Protective gas flow rate: 15L / min~25L / min for both front and back;

[0018] Welding location: Both ends of the butt weld of the workpiece to be welded.

[0019] Furthermore, the process parameters for laser welding are as follows:

[0020] Laser power: 1000W~8000W;

[0021] Welding speed: 1.0m / min~7.0m / min;

[0022] Defocusing amount: -5mm to 5mm;

[0023] Ultrasonic power: 240W~840W;

[0024] Protective gas: 99.99% Ar;

[0025] Protective gas flow rate: 15L / min~25L / min.

[0026] Furthermore, the method for homogenizing the reinforcing phase of aluminum-based composites by inserting ultrasonic vibration-assisted laser welding is carried out using a digital welding system. The digital welding system includes a laser welding system, an ultrasonic vibration system, and a PLC controller. The laser welding system and the ultrasonic vibration system are synchronized through the PLC controller. The ultrasonic vibration system includes an amplitude-modulated tungsten needle.

[0027] Furthermore, the tip of the variable amplitude tungsten needle is aligned with the center of the laser spot in the laser welding system.

[0028] Furthermore, the workpieces to be welded are pre-treated before mechanical assembly and laser spot welding.

[0029] Furthermore, the process of forming a keyhole during the initial welding includes a cooling step after the ultrasonically vibrating tungsten needle is inserted into the molten pool for stirring.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention uses a tungsten needle to directly apply ultrasonic vibration to the laser-welded molten pool, effectively improving the aggregation of reinforcing phases during welding. Compared to traditional methods that rely solely on optimizing welding parameters or adding filler material, this invention achieves a highly uniform distribution of reinforcing phases in the weld joint area, improving weld contour morphology and significantly enhancing weld quality. The tungsten needle ensures uniform stirring of materials within the molten pool, promoting fusion and reducing welding defects such as porosity and cracks, thereby improving weld quality. Furthermore, this invention allows for real-time adjustment of the tungsten needle insertion depth and vibration parameters according to the welding process, enhancing process flexibility and making it suitable for metal matrix composites of varying thicknesses and types.

[0032] Furthermore, this invention integrates a laser welding system and an ultrasonic vibration system using a PLC controller, simplifying the multiple process steps required for traditional welding, improving welding efficiency, and reducing production costs.

[0033] Furthermore, this invention can be widely applied in various metal matrix composites containing particulate reinforcing phases to achieve the effect of homogenizing the reinforcing phase particles in welded joints, and is not limited to a specific material system. By controlling the material behavior within the molten pool through ultrasonic vibration, the flexibility and stability of the welding process under different materials and welding environments are ensured, significantly broadening the scope of industrial applications. Attached Figure Description

[0034] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings;

[0035] Figure 1 A schematic diagram of the laser-ultrasonic welding method for Al-MMCs to enhance phase homogenization provided by the present invention;

[0036] In the diagram, 1 is the ultrasonic vibration system, 2 is the laser head, 3 is the laser beam, 4 is the amplitude-changing tungsten needle, and 5 is the copper pad.

[0037] Figure 2Image of a butt weld joint of 15% SiCp / 2Al4Al obtained by laser welding without applying ultrasonic vibration;

[0038] Figure 3 Image of a laser butt weld joint of 15% SiCp / 2A14Al with ultrasonic assistance;

[0039] Figure 4 for Figure 2 Microstructure of region A in the center of the weld;

[0040] Figure 5 for Figure 3 Microstructure of region B in the center of the weld;

[0041] Figure 6 This is a diagram showing the welding results of Comparative Example 2. Detailed Implementation

[0042] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0043] This invention proposes a method for homogenizing the reinforcing phase of aluminum-based composites using an insertion-type ultrasonic vibration-assisted laser welding process, comprising the following steps:

[0044] See Figure 1 The method of homogenizing the reinforcing phase of aluminum matrix composite by insertion ultrasonic vibration-assisted laser welding adopts a digital welding system. The digital welding system includes a laser welding system, an ultrasonic vibration system 1, and a PLC controller. The laser welding system and the ultrasonic vibration system are synchronized through the PLC controller. The laser welding system includes a laser head 2, which can emit a laser beam 3. The ultrasonic vibration system includes an amplitude-modulated tungsten needle 4 located at the end. During the actual welding, the amplitude-modulated tungsten needle 4 contacts the molten pool to realize a specific insertion and withdrawal operation.

[0045] Welding preparation steps: Select the size, volume fraction, and material thickness of the Al-MMCs reinforcing phase particles to be welded, such as silicon carbide particle-reinforced aluminum matrix composite material (SiCp / Al composite material) with a size of 5~40μm and a volume fraction of 5~25%, and pretreat the material to be welded; wherein, the pretreatment includes any one or more combinations of cleaning, alkaline washing, acid washing, and drying.

[0046] Fixing Steps: Mechanical assembly and laser spot welding are performed on both ends of the Al-MMCs to be welded, ensuring the stability of the workpiece during welding. Specifically, copper backing plates 5 are used for mechanical assembly of the materials to be welded. These copper backing plates 4 consist of two pairs of plates, with the lower plate having a groove to allow for positioning of the Al-MMCs by the back shielding gas. The laser spot welding process parameters are as follows:

[0047] Laser power: 800W~1500W;

[0048] Welding speed: 0.5m / min~1.0m / min;

[0049] Defocusing amount: -3mm to 3mm;

[0050] Protective gas: 99.99% Ar;

[0051] Protective gas flow rate: 15L / min~25L / min for both front and back;

[0052] Welding location: Both ends of the butt weld of the assembled workpieces to be welded;

[0053] Preferably, in the welding step, the process parameters for laser welding are as follows:

[0054] Laser power: 1000W~8000W;

[0055] Welding speed: 1.0m / min~7.0m / min;

[0056] Defocusing amount: -5mm to 5mm;

[0057] Ultrasonic power: 240W~840W;

[0058] Protective gas: 99.99% Ar;

[0059] Protective gas flow rate: 15L / min~25L / min;

[0060] Preparation steps for the ultrasonic vibration system: Install the amplitude-modulated tungsten needle of the ultrasonic vibration system onto the laser welding system; wherein, the amplitude-modulated tungsten needle can move synchronously with the laser beam and the tip of the amplitude-modulated tungsten needle is directly aligned with the center of the laser spot;

[0061] Welding steps: Butt welding is performed using a fiber laser and a digital welding system; specifically, when the keyhole is formed during the initial weld, a variable-amplitude tungsten needle is rapidly inserted into the molten pool for stirring.

[0062] Ultrasonic retraction step: At the end of welding, the amplitude-modulated tungsten needle is quickly pulled out of the molten pool by the PLC controller to avoid unnecessary interference during the cooling process of the weld joint.

[0063] In the fixing and welding steps, the areas of the Al-MMCs to be welded are in a clean and weldable state. The formal welding is performed using a fiber laser, which proceeds synchronously with the ultrasonic vibration system.

[0064] Preferably, the power and amplitude of the ultrasonic vibration system can be adjusted according to the material properties and welding conditions.

[0065] Preferably, the method for homogenizing the reinforcing phase of aluminum-based composites by insert-type ultrasonic vibration-assisted laser welding provided by the present invention further includes:

[0066] Cooling step: After the welding step is completed, the protective cover remains at the end point, and the protective gas is maintained for 10s~50s until it cools down to below the phase transition temperature of the material.

[0067] Example 1

[0068] A method for homogenizing the reinforcing phase in aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, employing a 2mm thick 15%SiCp / 2Al4Al workpiece as the workpiece to be welded, includes the following steps:

[0069] Welding preparation steps: Select 15%SiCp / 2A14Al as the Al-MMCs to be welded and perform pretreatment;

[0070] Fixing steps: Mechanical assembly and laser spot welding are performed to fix the two 15%SiCp / 2Al4Al workpieces to be welded;

[0071] Preparation steps for the ultrasonic vibration system: Install the ultrasonic vibration system on the laser welding system, ensuring that it can move synchronously with the laser and is accurately positioned.

[0072] Welding steps: The formal welding operation is carried out using a fiber laser and a digital welding system to butt weld 15% SiCp / 2A14Al composite material; when the keyhole is formed during the initial welding, the amplitude-modulated tungsten needle is quickly inserted into the molten pool for stirring.

[0073] Ultrasonic back-pulsation step: When welding is finished, quickly pull the ultrasonic amplitude tungsten needle out of the molten pool to avoid interfering with the joint cooling process.

[0074] The pretreatment includes mechanical grinding, alkaline washing, acid washing and drying to ensure that the surface to be welded is clean and free of oxides or oil.

[0075] In the fixing and welding steps, the areas of the 15%SiCp / 2Al4Al composite material to be welded are in a clean and weldable state, and the formal welding is performed using a fiber laser.

[0076] Preferably, the spot welding in the fixing step is laser spot welding. Both sides of the assembled 15%SiCp / 2Al4Al composite material are in a weldable state. The actual welding material is assembled tightly using two pairs of copper backing plates on each side, with the spot welding positions located at both ends of the weld seam.

[0077] Preferably, in the welding step, while the laser beam irradiates the docking position to form a keyhole, an ultrasonic amplitude-modulated tungsten needle is inserted into the molten pool to perform homogenization stirring.

[0078] Specifically:

[0079] In the fixed steps, the process parameters for laser spot welding are:

[0080] Laser power: 1000W;

[0081] Welding speed: 1.0 m / min;

[0082] Defocusing amount: 1mm;

[0083] Protective gas: 99.99% Ar;

[0084] Shielding gas flow rate: 15 L / min on both sides of the material to be welded;

[0085] Welding location: Both ends of the weld seam of the assembled 15%SiCp / 2A14Al composite material;

[0086] In the welding process, the process parameters for laser welding are as follows:

[0087] Laser power: 3000W;

[0088] Welding speed: 4.0 m / min;

[0089] Defocusing amount: -1mm;

[0090] Ultrasonic power: 500W;

[0091] Protective gas: 99.99% Ar;

[0092] Protective gas flow rate: 20L / min;

[0093] Cooling step: After the welding step is completed, the 15%SiCp / 2A14Al composite front protective cover remains at the end point, and the gas is held for 15 seconds until it cools to below 200℃.

[0094] Furthermore, the present invention provides a method for homogenizing the reinforcing phase of aluminum-based composites using an insert-type ultrasonic vibration-assisted laser welding process. This process is similar to conventional laser welding, including surface oil cleaning, alkaline washing, acid washing, drying, assembly, spot welding, and the final welding step. New solutions are proposed for the assembly method, spot welding method, final welding method, and cooling method. In the preferred embodiment mentioned in this invention, regarding the assembly method, the 15%SiCp / 2Al4Al composite material is clamped between four copper pads, positioned horizontally and vertically. For both the spot welding and final welding methods, fiber lasers are used for welding. Regarding the cooling method, after welding, cooling is performed by keeping the protective cover of the 15%SiCp / 2Al4Al composite material at the endpoint while continuously outputting protective gas for 15 seconds until it cools to below 200°C. The immersion ultrasonic-assisted laser welding of 15% SiCp / 2Al4Al composite material in Embodiment 1 of this invention addresses the problems of low joint quality, slow efficiency, uneven distribution of reinforcing phases, and limited industrial application in current laser welding of Al-MMCs. It proposes a new assembly, welding, and cooling scheme. By employing a copper pad clamping assembly method, heat dissipation of the materials to be welded is accelerated, preventing thermal deformation, eliminating numerous operational steps, significantly simplifying the production process, and improving welding efficiency. Through the coupling of the immersion ultrasonic vibration system and the laser system, the molten pool of Al-MMCs at the weld is directly stirred, homogenizing the distribution of the reinforcing phase. The precise design of the ultrasonic composite laser welding system perfectly achieves the homogenization of the reinforcing phase, improving joint quality.

[0095] Example 2

[0096] A method for homogenizing the reinforcing phase of aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, employing a welding method for 3 mm thick 10% SiCp / 2009Al composite materials, comprises the following steps:

[0097] (1) After selecting the type and thickness of Al-MMCs as 3mm 10%SiCp / 2009Al, the insertion depth of the ultrasonic amplitude tungsten needle was changed to 2.8mm according to the material thickness;

[0098] (2) The 10%SiCp / 2009Al composite material was manufactured by machine milling, and the sides to be welded were smoothed in particular;

[0099] (3) The 10%SiCp / 2009Al composite material was cleaned of oil, alkali, acid and dried to remove surface impurities and keep the welding position clean.

[0100] (4) The two workpieces of 10%SiCp / 2009Al to be welded are mechanically assembled and fixed by laser spot welding to ensure stability during the welding process. The main process parameters of spot welding are: laser power 1200W, welding speed 1.0m / min, defocusing amount -1mm, shielding gas 99.99%Ar, shielding gas flow rate 15L / min.

[0101] (5) Install the ultrasonic vibration system on the laser welding system to ensure that it can be accurately inserted into the molten pool and move synchronously with the laser;

[0102] (6) The formal welding operation was carried out by a digital welding system coupled with fiber laser and ultrasonic vibration. The 10%SiCp / 2009Al composite material was butt welded. At the same time as the laser started welding, the ultrasonic amplitude tungsten needle was inserted into the molten pool for stirring. The formal welding process parameters were: laser power 5000W, welding speed 4.0m / min, defocusing amount -1mm, ultrasonic power 600W, shielding gas 99.99%Ar, and shielding gas flow rate of 20L / min for both the front and back sides.

[0103] (7) When the welding is finished, the ultrasonic amplitude tungsten needle is quickly withdrawn;

[0104] (8) After welding, continue to output the protective gas flow for 30 seconds until the weld joint cools down to a lower temperature.

[0105] Example 3

[0106] A method for homogenizing the reinforcing phase in aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, employing a 2mm thick 15%SiCp / 2Al4Al workpiece as the workpiece to be welded, includes the following steps:

[0107] Welding preparation steps: Select 5%SiCp / 2A14Al as the Al-MMCs to be welded and perform pretreatment;

[0108] Fixing steps: Mechanical assembly and laser spot welding are performed to fix the two workpieces to be welded, which are 5%SiCp / 2Al4Al.

[0109] Preparation steps for the ultrasonic vibration system: Install the ultrasonic vibration system on the laser welding system, ensuring that it can move synchronously with the laser and is accurately positioned.

[0110] Welding steps: The formal welding operation is carried out using a fiber laser and a digital welding system to butt weld 5% SiCp / 2A14Al composite material;

[0111] Ultrasonic back-pulsation step: When welding is finished, quickly pull the ultrasonic amplitude tungsten needle out of the molten pool to avoid interfering with the joint cooling process.

[0112] The pretreatment includes mechanical grinding, alkaline washing, acid washing and drying to ensure that the surface to be welded is clean and free of oxides or oil.

[0113] In the fixing and welding steps, the areas of the 5%SiCp / 2Al4Al composite material to be welded are in a clean and weldable state, and the formal welding is performed using a fiber laser.

[0114] Preferably, the spot welding in the fixing step is laser spot welding. Both sides of the assembled 5%SiCp / 2Al4Al composite material are in a weldable state. The actual welding material is assembled tightly using two pairs of copper backing plates on each side, with the spot welding positions located at both ends of the weld seam.

[0115] Preferably, in the welding step, while the laser beam irradiates the docking position to form a keyhole, an ultrasonic amplitude-modulated tungsten needle is inserted into the molten pool to perform homogenization stirring.

[0116] Specifically:

[0117] In the fixed steps, the process parameters for laser spot welding are:

[0118] Laser power: 800W;

[0119] Welding speed: 1.0 m / min;

[0120] Defocusing amount: -3mm;

[0121] Protective gas: 99.99% Ar;

[0122] Shielding gas flow rate: 20 L / min on both sides of the material to be welded;

[0123] Welding location: Both ends of the weld seam to be welded on the assembled 5%SiCp / 2A14Al composite material;

[0124] In the welding process, the process parameters for laser welding are as follows:

[0125] Laser power: 1000W;

[0126] Welding speed: 1.0 m / min;

[0127] Defocusing amount: -4mm;

[0128] Ultrasonic power: 240W;

[0129] Protective gas: 99.99% Ar;

[0130] Protective gas flow rate: 25L / min;

[0131] Cooling step: After the welding step is completed, the 5%SiCp / 2A14Al composite front protective cover remains at the end point, and the gas is held for 10 seconds until it cools to below 200℃.

[0132] Example 4

[0133] A method for homogenizing the reinforcing phase in aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, employing a 2mm thick 25%SiCp / 2Al4Al workpiece as the workpiece to be welded, includes the following steps:

[0134] Welding preparation steps: Select 25%SiCp / 2A14Al as the Al-MMCs to be welded and perform pretreatment;

[0135] Fixing steps: Mechanical assembly and laser spot welding are performed to fix the two 25%SiCp / 2Al4Al workpieces to be welded;

[0136] Preparation steps for the ultrasonic vibration system: Install the ultrasonic vibration system on the laser welding system, ensuring that it can move synchronously with the laser and is accurately positioned.

[0137] Welding steps: The formal welding operation is carried out using a fiber laser and a digital welding system to butt weld the 25% SiCp / 2A14Al composite material.

[0138] Ultrasonic back-pulsation step: When welding is finished, quickly pull the ultrasonic amplitude tungsten needle out of the molten pool to avoid interfering with the joint cooling process.

[0139] The pretreatment includes mechanical grinding, alkaline washing, acid washing and drying to ensure that the surface to be welded is clean and free of oxides or oil.

[0140] In the fixing and welding steps, the areas of the 25%SiCp / 2A14Al composite material to be welded are in a clean and weldable state, and the formal welding is performed using a fiber laser.

[0141] Preferably, the spot welding in the fixing step is laser spot welding. Both sides of the assembled 25%SiCp / 2Al4Al composite material are in a weldable state. The actual welding material is assembled tightly using two pairs of copper backing plates on each side, with the spot welding positions located at both ends of the weld seam.

[0142] Preferably, in the welding step, while the laser beam irradiates the docking position to form a keyhole, an ultrasonic amplitude-modulated tungsten needle is inserted into the molten pool to perform homogenization stirring.

[0143] Specifically:

[0144] In the fixed steps, the process parameters for laser spot welding are:

[0145] Laser power: 1500W;

[0146] Welding speed: 0.5 m / min;

[0147] Defocusing amount: 2mm;

[0148] Protective gas: 99.99% Ar;

[0149] Shielding gas flow rate: 25 L / min on both sides of the material to be welded;

[0150] Welding location: Both ends of the weld seam of the assembled 25%SiCp / 2A14Al composite material;

[0151] In the welding process, the process parameters for laser welding are as follows:

[0152] Laser power: 8000W;

[0153] Welding speed: 5.0 m / min;

[0154] Defocusing distance: 5mm;

[0155] Ultrasonic power: 800W;

[0156] Protective gas: 99.99% Ar;

[0157] Protective gas flow rate: 15L / min;

[0158] Cooling step: After the welding step is completed, the 25%SiCp / 2A14Al composite front protective cover remains at the end point, and the gas is held for 30 seconds until it cools to below 200℃.

[0159] Example 5

[0160] A method for homogenizing the reinforcing phase of aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, employing a welding method for 3 mm thick 10% SiCp / 2009Al composite materials, comprises the following steps:

[0161] (1) After selecting the type and thickness of Al-MMCs as 3mm 10%SiCp / 2009Al, the insertion depth of the ultrasonic amplitude tungsten needle was changed to 2.8mm according to the material thickness;

[0162] (2) The 10%SiCp / 2009Al composite material was manufactured by machine milling, and the sides to be welded were smoothed in particular;

[0163] (3) The 10%SiCp / 2009Al composite material was cleaned of oil, alkali, acid and dried to remove surface impurities and keep the welding position clean.

[0164] (4) The two workpieces of 10%SiCp / 2009Al to be welded are mechanically assembled and fixed by laser spot welding to ensure stability during the welding process. The main process parameters of spot welding are: laser power 1300W, welding speed 0.7m / min, defocusing amount 3mm, shielding gas 99.99%Ar, shielding gas flow rate 15L / min.

[0165] (5) Install the ultrasonic vibration system on the laser welding system to ensure that it can be accurately inserted into the molten pool and move synchronously with the laser;

[0166] (6) The formal welding operation was carried out by a digital welding system coupled with fiber laser and ultrasonic vibration. The 10%SiCp / 2009Al composite material was butt welded. At the same time as the laser started welding, the ultrasonic amplitude tungsten needle was inserted into the molten pool for stirring. The formal welding process parameters were: laser power 5000W, welding speed 7.0m / min, defocusing amount -5mm, ultrasonic power 500W, shielding gas 99.99%Ar, and shielding gas flow rate of 20L / min for both the front and back sides.

[0167] (7) When the welding is finished, the ultrasonic amplitude tungsten needle is quickly withdrawn;

[0168] (8) After welding, continue to output the protective gas flow for 30 seconds until the weld joint cools down to a lower temperature.

[0169] Comparative Example 1

[0170] Similar to Example 1, but without applying ultrasonic vibration, laser welding was performed directly. The resulting microstructure of the 15% SiCp / 2Al4Al butt weld joint is as follows: Figure 2 As shown.

[0171] The microstructure of the welded joint of the 15% SiCp / 2Al4Al composite material prepared in Example 1 is as follows: Figure 3 and Figure 5 As shown, it can be seen that the comparison... Figure 2 and Figure 4 Laser welded joints without ultrasonic treatment, from Figure 3 and Figure 5 It is evident that after applying ultrasonic assistance, the weld contour shape is improved, porosity is reduced, and the reinforcing phase particles in the joint do not show obvious segregation and growth. The reinforcing phase is evenly distributed, the matrix grains are refined to a certain extent, and the welding quality is better.

[0172] Comparative Example 2

[0173] A method for homogenizing the reinforcing phase of aluminum-based composites using an insertion-type ultrasonic vibration-assisted laser welding method is disclosed. The method employs an ultrasonic vibration-coupled laser welding method for 2 mm thick 15% SiCp / 2Al4Al composite materials. The steps are as follows:

[0174] After welding, remove the workpiece to inspect the weld. See [reference needed]. Figure 6 It was found that when the ultrasonic power was too high, the unsuitable vibration parameters completely cracked the weld and heat-affected zone of the 15%SiCp / 2A14Al composite material, causing the weld to fall off completely and making it impossible to form a connection. Therefore, it is necessary to use the ultrasonic power range in this invention.

[0175] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0176] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for homogenizing the reinforcing phase in aluminum-based composites using immersion ultrasonic vibration-assisted laser welding, characterized in that, Includes the following steps: Mechanical assembly and laser spot welding are performed on the workpieces to be welded. When performing the formal welding operation on the workpiece to be welded, when the keyhole is formed during the initial welding, an ultrasonically vibrating tungsten needle is inserted into the molten pool to stir and complete the welding. The method for homogenizing the reinforcing phase of aluminum-based composites by insert-type ultrasonic vibration-assisted laser welding is carried out using a digital welding system. The digital welding system includes a laser welding system, an ultrasonic vibration system, and a PLC controller. The laser welding system and the ultrasonic vibration system are synchronized through the PLC controller. The ultrasonic vibration system includes an amplitude-modulated tungsten needle. The tip of the amplitude-modulated tungsten needle is aligned with the center of the laser spot of the laser welding system. When the keyhole is formed during the initial welding, an ultrasonically vibrating tungsten needle is inserted into the molten pool for stirring. After the welding is completed and the laser beam is turned off and the molten pool solidifies, the ultrasonically vibrating tungsten needle is pulled back in time by the PLC controller. The workpiece to be welded is an aluminum-based composite material reinforced with silicon carbide particles; The silicon carbide particles have a size of 5~40μm, and the volume fraction of the silicon carbide particle reinforcing phase is 5%~25%. The process parameters for laser spot welding are: Laser power: 800W~1500W; Welding speed: 0.5m / min~1.0m / min; Defocusing amount: -3mm to 3mm; Protective gas: 99.99% Ar; Protective gas flow rate: 15L / min~25L / min for both front and back; Welding location: Both ends of the butt weld of the workpiece to be welded; The process parameters for laser welding are as follows: Laser power: 1000W~8000W; Welding speed: 1.0m / min~7.0m / min; Defocusing amount: -5mm to 5mm; Ultrasonic power: 240W~840W; Protective gas: 99.99% Ar; Protective gas flow rate: 15L / min~25L / min; The process of forming a keyhole during the initial welding involves inserting an ultrasonically vibrating tungsten needle into the molten pool for stirring, followed by a cooling step.

2. The method for homogenizing the reinforcing phase of aluminum matrix composites by insertion-type ultrasonic vibration-assisted laser welding according to claim 1, characterized in that, The mechanical assembly and laser spot welding of the workpiece to be welded includes the following steps: the workpiece to be welded is mechanically assembled using copper pads, wherein the copper pads consist of two pairs of upper and lower copper pads with a groove on the lower pad, the workpiece to be welded is positioned, and then the two ends are fixed by laser spot welding.

3. The method for homogenizing the reinforcing phase of aluminum matrix composites by insertion-type ultrasonic vibration-assisted laser welding according to claim 1, characterized in that, Pre-treatment of the workpieces to be welded is performed before mechanical assembly and laser spot welding.

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