阅读说明：本技术 焊接铝基复合材料和钛合金使焊缝金属间化合物颗粒弥散强化的钎焊方法 (Brazing method for welding aluminum-based composite material and titanium alloy to strengthen particles of intermetallic compound of welding line in dispersion mode ) 是由 许志武 李政玮 柴本 闫久春 于 2019-12-03 设计创作，主要内容包括：焊接铝基复合材料和钛合金使焊缝金属间化合物颗粒弥散强化的钎焊方法,本发明涉及铝基复合材料和钛合金钎焊领域。本发明要解决现有焊接铝基复合材料和钛合金方法,获得的接头性能低的技术问题。方法：一、将纯铝锭熔化；二、对钛合金表面进行改性；三、超声焊接。本发明可明显降低钛合金和铝基复合材料的焊接温度,有效防止焊接过程中母材的受热软化,且进入焊缝的TiAl<Sub>3</Sub>颗粒可起到弥散强化的作用,有利于获得高强度的焊接接头。本发明方法用于钎焊铝基复合材料和钛合金。(The invention discloses a brazing method for welding an aluminum-based composite material and a titanium alloy to disperse and strengthen intermetallic compound particles of a weld joint, and relates to the field of brazing of the aluminum-based composite material and the titanium alloy. The invention aims to solve the technical problem that the joint obtained by the existing method for welding the aluminum-based composite material and the titanium alloy is low in performance. The method comprises the following steps: firstly, melting a pure aluminum ingot; secondly, modifying the surface of the titanium alloy; and thirdly, ultrasonic welding. The invention can obviously reduce the welding temperature of the titanium alloy and the aluminum-based composite material, effectively prevent the heating softening of the base metal in the welding process and prevent the TiAl entering the welding line 3 The particles can play a role in dispersion strengthening, and are beneficial to obtaining high-strength welding joints. The method of the invention is used for brazing aluminum-based composite materials and titanium alloys.)

1. The brazing method for welding the aluminum-based composite material and the titanium alloy to disperse and strengthen the particles of the intermetallic compound of the welding seam is characterized by comprising the following steps:

firstly, putting a pure aluminum ingot into a brazing filler metal groove, and heating and melting to obtain a modified molten liquid;

secondly, immersing the titanium alloy into the modified molten liquid obtained in the first step, applying ultrasonic waves to modify the surface of the titanium alloy, then preserving the heat for 10 min-1 h, taking out, air-cooling and polishing the surface to obtain the titanium alloy with a modified layer;

and thirdly, brazing filler metal is placed between the aluminum-based composite material and the titanium alloy with the modified layer obtained in the second step, and ultrasonic welding is carried out to complete the method.

2. The brazing method for diffusion strengthening of particles of intermetallic compounds of weld joints by welding of aluminum-based composite material and titanium alloy according to claim 1, characterized in that in the first step, heating is carried out to 700 to 720 ℃ to melt pure aluminum ingot.

3. The brazing method for welding the aluminum-based composite material and the titanium alloy to strengthen the grain dispersion of the intermetallic compound of the weld according to claim 1, wherein the titanium alloy in the second step is commercially pure titanium TA1-4, TA15 titanium alloy, TC1-26 titanium alloy, TA5-28 titanium alloy or TB2-11 titanium alloy.

4. The brazing method for diffusion strengthening of particles of intermetallic compounds of a weld joint by welding of aluminum-based composite material and titanium alloy according to claim 1, wherein the size of titanium alloy in the second step is 10mm x 3 mm.

5. The brazing method for carrying out dispersion strengthening on particles of a weld intermetallic compound by welding an aluminum-based composite material and a titanium alloy according to claim 1, wherein in the second step, the frequency of ultrasonic waves is controlled to be 15 to 50kHz, the amplitude is controlled to be 4 to 15 μm, the power is controlled to be 100 to 2000W, and the ultrasonic loading time is controlled to be 1 to 100 s.

6. The brazing method for carrying out the dispersion strengthening of the particles of the intermetallic compound in the weld joint by welding the aluminum-based composite material and the titanium alloy according to claim 1, wherein the temperature for the second step is 700 to 720 ℃.

7. The brazing method for welding the aluminum-based composite material and the titanium alloy to disperse and reinforce the particles of the intermetallic compound of the weld according to claim 1, wherein the aluminum-based composite material in the third step is a carbon fiber reinforced aluminum-based composite material or a SiC reinforced aluminum-based composite material.

8. The brazing method for carrying out the dispersion strengthening on the particles of the intermetallic compound of the welding seam by welding the aluminum-based composite material and the titanium alloy according to claim 1, which is characterized in that the ultrasonic welding is carried out in the third step, wherein the ultrasonic frequency is controlled to be 15-50 kHz, the amplitude is 4-15 μm, the power is 100-2000W, and the ultrasonic loading time is 1-100 s.

9. The brazing method for strengthening the dispersion of the particles of the intermetallic compound of the weld joint by welding the aluminum-based composite material and the titanium alloy according to claim 1, wherein the brazing filler metal in the third step is an Sn-based brazing filler metal, and the brazing temperature is controlled to be 200 to 400 ℃ during brazing.

10. The brazing method for strengthening the dispersion of the particles of the intermetallic compound of the weld joint by welding the aluminum-based composite material and the titanium alloy according to claim 1, wherein the brazing filler metal in the third step is a Zn-based brazing filler metal, and the brazing temperature is controlled to be 400 to 550 ℃ during brazing.

Technical Field

The invention relates to the field of brazing of aluminum-based composite materials and titanium alloys.

Background

The aerospace craft has the characteristics of high temperature resistance, high speed, strong maneuverability, large load, long voyage and the like, and has more and more rigorous requirements on the material performance of the craft, particularly on the aspect of light structure. The novel light high-strength material can not only improve various performances of the aircraft, but also reduce the manufacturing cost. The aluminum-based composite material has the advantages of low density, high strength, high rigidity and the like, and has great application potential in the fields of aerospace, automobiles, electronics and the like. The titanium alloy has strong high temperature resistance and excellent mechanical property, and is widely applied in the fields of aerospace, ships and the like in China.

The aluminum-based composite material and the titanium alloy are used as two materials with wide application prospects, the connection between the aluminum-based composite material and the titanium alloy can make up for the shortages, and the application range is extremely wide, so that the research on the connection between the aluminum-based composite material and the titanium alloy has great theoretical and practical significance.

Welding of aluminum-based composites and titanium alloys remains a difficult problem in modern manufacturing. Because the titanium alloy has good thermal stability and the surface of the titanium alloy is easy to form an oxide film, the titanium alloy belongs to a material difficult to wet, the welding process generally needs a vacuum environment and certain heat preservation time, the welding efficiency is low, and the performance of a joint is not high. Therefore, the invention discloses a welding method of an aluminum-based composite material and a titanium alloy, which is efficient, can be carried out in an atmospheric environment and can obtain a high-strength joint.

Disclosure of Invention

The invention provides a brazing method for welding an aluminum-based composite material and a titanium alloy to disperse and strengthen intermetallic compound particles of a welding seam, aiming at solving the technical problem of low performance of a joint obtained by the existing method for welding the aluminum-based composite material and the titanium alloy.

The brazing method for welding the aluminum-based composite material and the titanium alloy to disperse and strengthen the particles of the intermetallic compound of the welding line comprises the following steps:

firstly, putting a pure aluminum ingot into a brazing filler metal groove, and heating and melting to obtain a modified molten liquid;

secondly, immersing the titanium alloy into the modified molten liquid obtained in the first step, applying ultrasonic waves to modify the surface of the titanium alloy, then preserving the heat for 10 min-1 h, taking out, air-cooling and polishing the surface to obtain the titanium alloy with a modified layer;

and thirdly, brazing filler metal is placed between the aluminum-based composite material and the titanium alloy with the modified layer obtained in the second step, and ultrasonic welding is carried out to complete the method.

And in the second step, ultrasonic waves are utilized to realize rapid surface modification of the titanium alloy, the grain reinforcement of the intermetallic compound of the titanium alloy modification layer is realized within the heat preservation time, and then the titanium alloy after the surface modification is ground, namely the part which does not form the grain reinforcement of the intermetallic compound is ground.

Further, in the second step, the frequency of the ultrasonic wave is controlled to be 15-50 kHz, the amplitude is controlled to be 4-15 mu m, the power is controlled to be 100-2000W, and the ultrasonic loading time is controlled to be 1-100 s.

Further, in the third step of ultrasonic welding, the ultrasonic frequency is controlled to be 15-50 kHz, the amplitude is controlled to be 4-15 mu m, the power is 100-2000W, and the ultrasonic loading time is 1-100 s.

Furthermore, the brazing filler metal in the third step is Sn-based brazing filler metal, and the brazing temperature is controlled to be 200-400 ℃ during brazing.

Furthermore, the brazing filler metal in the third step is Zn-based brazing filler metal, and the brazing temperature is controlled to be 400-550 ℃ during brazing.

The invention firstly utilizes the acoustic cavitation of the liquid brazing filler metal under the action of ultrasonic waves to realize the rapid surface modification of the titanium alloy, then realizes the particle enhancement of the intermetallic compound of the modified layer within a certain heat preservation time, and finally completes the ultrasonic welding process within a very short time and at a lower temperature. In the welding process, particles of intermetallic compounds in the modified layer can enter the welding line, and the effect of dispersion strengthening is realized on the welding line. The invention can be carried out in atmospheric environment without vacuum or protective gas; the time for the surface modification process, the heat preservation after modification and the welding is short, and the welding efficiency is high; the temperature in the surface modification and welding process is low, and the base metal is not melted; the obtained joint has high strength which can reach more than 70 MPa; in addition, the modification layer and the welding seam reinforced by the intermetallic compound particles can also ensure that the titanium alloy and aluminum matrix composite material joint can keep certain strength at high temperature.

The invention has the beneficial effects that:

the invention firstly carries out surface modification on the titanium alloy by the main means of ultrasonic waveThe auxiliary method is characterized in that the acoustic cavitation phenomenon of liquid brazing filler metal (the melting point is lower than that of titanium alloy) under the ultrasonic action is utilized to remove an oxide film on the surface of a titanium alloy base metal, and then the brazing filler metal and the titanium alloy are combined to form a low-melting-point modified layer on the surface of the titanium alloy base metal, so that the purpose of reducing the welding temperature is achieved. The strength of the brazing filler metal used for the surface modification of the titanium alloy must not be too low, otherwise the overall joint performance will be degraded. After surface modification, TiAl dispersed in the modified layer is generated by prolonging the heat preservation time₃Particles, thereby improving the strength of the modified layer. In addition, the titanium alloy and the aluminum-based composite material with the modified surfaces are subjected to ultrasonic-assisted welding, and the welding process also utilizes ultrasonic assistance. In this case, the brazing filler metal may be selected from low-temperature or medium-temperature brazing filler metals, but the melting point of the brazing filler metal should be lower than the liquidus line of the aluminum matrix composite. TiAl in the modified layer during soldering₃The particles can enter the welding line and play a role in dispersion strengthening on the welding line. In addition, the liquid brazing filler metal can generate a large amount of cavitation bubbles under the action of ultrasonic waves, and special phenomena such as local high temperature, high pressure and high-speed liquid flow generated after the cavitation bubbles are collapsed can enable the titanium alloy and the aluminum-based composite material to be welded in a very short time. The invention can obviously reduce the welding temperature of the titanium alloy and the aluminum-based composite material, effectively prevent the heating softening of the base metal in the welding process and prevent the TiAl entering the welding line₃The particles can play a role in dispersion strengthening, and are beneficial to obtaining high-strength welding joints.

In conclusion, the welding method has the following beneficial effects:

1. the randomness of the material to be welded. The invention can select titanium alloy and aluminum-based composite material at will without the limit of the base material components.

2. The selection and the component proportion of the brazing filler metal in the welding process are flexible. The invention can use any brazing filler metal, can be used at high and low temperatures, has flexible component proportion, and can be a single component or a composite brazing filler metal.

3. The welding process has low temperature and wide selectable range. The invention can select proper brazing filler metal according to the use condition of the test piece, and then select the welding temperature according to the components of the brazing filler metal. For example, the soldering temperature of the Sn-9Zn solder can be about 200 ℃, and the soldering temperature of the Zn-5Al solder can be about 400 ℃.

4. The application position of the ultrasound is flexible. In the surface modification process, the ultrasonic waves can be loaded at any position of the clamp and are not limited by the position and the distance; in the welding process, ultrasonic waves can be loaded on a material to be welded and can also be applied on a clamp; the ultrasound may be applied continuously or intermittently.

5. The strength of the surface modification layer is high. For example, TA15 titanium alloy can be obtained from TiAl by ultrasonically assisted surface modification with pure aluminum₃A particle reinforced modified layer having a shear strength in excess of 140 MPa.

6. The strength of the joint is high. TiAl of modified layer during welding₃The particles can directly enter the welding line and are dispersed and distributed, the particles can be reinforced for the welding line, and the strength of the obtained joint is higher than that of the brazing filler metal.

7. Low cost, strong adaptability and high welding efficiency. The welding can be finished in the atmospheric environment and is hardly influenced by the surrounding environment.

8. The invention has wide application range, and is suitable for welding materials with various thicknesses and various complex parts.

The method of the invention is used for brazing aluminum-based composite materials and titanium alloys.

Drawings

FIG. 1 is a schematic view of surface modification of a titanium alloy in accordance with one step of an embodiment;

FIG. 2 is a schematic illustration of one step three ultrasonic welding of an embodiment;

FIG. 3 is a scanning electron microscope image of a titanium alloy with a modified layer obtained in step three of the example;

FIG. 4 is a scanning electron microscope image of a brazed joint obtained in the first example;

FIG. 5 is a scanning electron microscope image of a titanium alloy with a modified layer obtained in the third step of the second embodiment.

Detailed Description

The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.