CN105458547A - Active brazing filler metal suitable for cast aluminum-based composite material reinforced through high-volume-fraction SiC and preparation method of active brazing filler metal - Google Patents

Abstract

The invention discloses active brazing filler metal suitable for a cast aluminum-based composite material reinforced through high-volume-fraction SiC and a preparation method of the active brazing filler metal. The brazing filler metal comprises melting-point depressant type active elements of Ga, Ma and a melting-point accelerant type element Ti. One the aspect of interface wettability, the brazing filler metal has good wetting effect on the high-volume-fraction SiC, and in-situ reinforcement of a brazing seam can be achieved. The shearing strength of the brazing filler metal is two to three times that of other brazing filler metal and is 98.8% that of base metal under the condition that brazing of SiCp/ZL101 with the volume ratio being 70% is conducted at 500 DEG C and 1.5 MPa for 30 min, and fracture paths extend into the base metal, and few part fractured along an interface of the base metal and the brazing filler metal, so that in-situ reinforcing active liquid phase diffusion welding of the cast aluminum-based composite material reinforced through high-volume-fraction SiC particles is achieved.

Description

A kind of active solder suitable for high volume fraction SiC strengthened cast aluminum matrix composite material and preparation method thereof

technical field

The invention belongs to the field of welding material preparation and welding technology, and mainly relates to the component design, preparation and brazing process of active solder for aluminum-based composite materials, especially for high-volume SiC particle-reinforced cast aluminum-based composite materials (70vol.% SiCp/ ZL101) "in-situ enhanced active liquid phase diffusion welding" under medium and low temperature conditions.

Background technique

Aluminum matrix composites are widely used in aerospace, automotive engine cylinders and other fields due to their high specific strength and specific stiffness, low thermal expansion coefficient, high thermal conductivity, high wear resistance, high fatigue and creep resistance, etc. However, due to the existence of the ceramic particle reinforcement phase in the aluminum matrix composite material, the weldability of the traditional fusion welding method to the aluminum matrix composite material is seriously deteriorated (reference [1]), mainly manifested in the harmful interface between the SiC particles and the superheated aluminum liquid Reaction (brittle, deliquescent, acicular Al ₄ C ₃ ) and ceramic particles segregate in the center of the weld. If brazing is used, the ceramic reinforcement phase deteriorates the wettability of the interface between the brazing filler metal and the composite base metal. Because the surface of the composite material is the interface where the metal matrix and the ceramic reinforcement phase coexist, the interface between the composite material and the solder can be divided into two categories: the metal solder and the metal matrix interface (M/M interface); the ceramic particle and the metal solder interface (P/M interface). There are two main problems in the brazing of aluminum matrix composites: one is the poor wettability of the P/M interface, especially for the composite material base material reinforced with high volume fraction ceramic particles, the wettability of the P/M interface is even worse; the other is the brazing The uniformity of strengthening phase distribution in fractures; the former is more critical (reference [2]).

In order to solve the above problems, it is necessary to carry out characteristic and targeted improvement research in many aspects such as brazing methods, brazing materials and brazing metallurgy. The research on the improvement of the brazing process of aluminum matrix composite materials at home and abroad is mainly divided into two categories: one is to focus on the improvement of the brazing method for the purpose of film removal. Yan Jiuchun of Harbin Institute of Technology and others proposed a brazing method assisted by ultrasonic vibration, using Zn-4Al-3Cu solder to weld 30vol.% Al ₂ O _3P /6061Al, which can obtain high-strength, large-scale brazing under atmospheric and low temperature conditions Linkers (References [3-7]). The second is to optimize and improve the composition design of the intermediate layer or solder from different angles. Looking at the intermediate layers or solders that have been reported so far, there are mainly: (1) pure Cu, pure Ag intermediate layers, etc.: the disadvantage is that it is easy to cause particle segregation and deteriorate the joint strength (references [8,9]). Particle segregation can be mitigated by using thinner elemental interlayers, alloy interlayers, or combined solder layers (Ref. [10]). (2) Powder intermediate layer: When Huang Jihua et al. used Al-40.7Ag-19.3Cu-3Ti mixed powder solder to weld 15vol.% SiCp/2009Al, the joint strength was improved to a certain extent, but more Al was generated inside the brazing seam ₃ Ti (around the unmelted Ti powder), Al ₂ Cu, Ag ₂ Al brittle intermetallic compounds, which deteriorate joint performance (Reference [11]). (3) Pre-plating Ni layer: Niu Jitai et al., in the brazing of 55vol.% SiCp/ZL101 composite material and Kovar alloy 4J29, first electroplated a layer of Ni with a thickness of about 40 μm on the surface of the composite material, and then used Zn-58Cd-2Ag- 2Cu alloy solder brazing improves the wettability of the joint interface (Reference [12]). (4) Mg-containing low-melting-point brazing filler metal: Zou Jiasheng et al. used Al-28Cu-5Si-2Mg alloy brazing filler metal (melting point 580-590° C.) for the 10vol.% SiCp/2024Al low-volume fraction composite base material to realize brazing connection , Mg and Si diffused into the base metal form a low melting point Al-Si-Mg alloy and melt, thereby destroying the combination of the surface oxide film and the base metal, compared with Al-28Cu-5Si solder, greatly improving the interface wettability (ref. [13]). However, most of these traditional solders for Al matrix composites mainly focus on achieving film breakage and improving the wettability of the base metal matrix/metal solder (M/M) interface, basically ignoring the low-shear joints. The main reason for the strength is the improvement of the poor wettability of the parent metal strengthening phase/brazing filler metal (P/M) interface.

In 2008, for the improvement of the poor wettability of the P/M interface, Zhang Guifeng of Xi'an Jiaotong University (references [14-17]) proposed active-transient liquid phase bonding (A-TLP), that is, in the traditional alloy Active elements such as Ti that can react with ceramic reinforcement are added to the brazing filler metal. This method aims to improve the wettability of the P/M interface by inducing the reactive wetting of the P/M interface and strengthening the liquefaction and removal of the film under the film through the metallurgical action of active elements such as Ti in the welding process; on the other hand, by adding Melting element (melting point is higher than Al and has no eutectic reaction with Al), the high melting point intermetallic compound phase (formed by aluminum and melting element) dispersed and crystallized during isothermal solidification is used as the raw material of solid solution brazing joint after isothermal solidification In-situ strengthening phase is obtained to obtain in-situ strengthening brazing joint (reference [17]). This kind of active liquid phase diffusion welding that can obtain in situ strengthened braze is called "in situ enhanced active liquid phase diffusion welding" (InsituActive-TLPbonding, InsituActive-TLP, reference [2]). For the low volume fraction 10vol.% SiCp/ZL101 composite material, the applicant used the Al-19Cu-1Ti intermediate layer to realize InsituA-TLP, which not only has good interface wetting, but also obtains in-situ strengthened brazing joints, and the joints are sheared and fractured The paths are almost entirely inside the composite parent metal, resulting in strong joints with an efficiency factor of up to 99% (Refs [2,17]). However, when the applicant used the above-mentioned Al-19Cu-1Ti interlayer developed earlier to braze high volume fraction 70vol.% SiCp/ZL101 composite materials, the wettability was poor (even including the M/M interface), and the joint strength was low (40MPa). Subsequently, the applicant developed the Al-Cu-Mg-Ti active solder, which can increase the shear strength of the joint to about 60MPa[16], but the brazing temperature is high (600°C) but the strength is not very high. .

Since the melting point of the traditional Al-12Si eutectic solder (HL400) is too high (577°C), it cannot be used for ZL101-based composites (solidus 557°C), so other researchers have improved the design of solders for ZL101-based composites. On the one hand, the idea of adding Mg and Ni to traditional solders (such as low melting point HL401 and HL402, solidus about 525°C) is mainly adopted, but the effect is limited in terms of reducing the melting point of solder and improving wettability. For example, Wang Kehong's research group used two kinds of powdered brazing filler metals, Al-15Cu-8Si-4Ni-1.5Mg (melting point 593°C) and Al-20Cu-12.5Si-2Ni-1.5Mg (melting point 584°C) containing Mg and Ni. The 70vol.% SiCp/ZL101 aluminum matrix composite material is vacuum brazed at a higher temperature, and the brazing shear strength of the joint is the highest at 49.7MPa (reference [18]). Niu Jitai’s research group used Al-22Cu-7Si-1Mg-1Ni five-element alloy brazing filler metal containing Mg and Ni to carry out vacuum brazing on 60vol% SiCP/6063A composite material, and the maximum joint shear strength was 89.6 MPa (reference [19]).

The wettability of aluminum matrix composites during brazing will become worse with the increase of the volume fraction of the ceramic reinforcement phase, so that the active solder (Al-19Cu-1Ti), which is excellent for the base metal with low volume fraction, will Fraction (70vol.%) base metal showed very poor wettability and very low strength, although the matrix composition and reinforcement phase category of the composite base metal did not change, only the volume fraction of ceramic reinforcement phase increased. Therefore, it is extremely necessary to develop a new active solder system for difficult-to-wet high-volume-fraction aluminum matrix composites to achieve the desired "in-situ enhanced active liquid phase diffusion welding".

references:

[1] Chen Maoai. Welding of composite materials. Chemical Industry Press, 2005.

[2] Zhang Guifeng, Liao Xianjin, Chen Bo, Zhang Linjie, Zhang Jianxun. SiCp/ZL101 Aluminum Matrix Composites In Situ Enhanced Active Liquid Phase Diffusion Welding Method (InsituA-TLP). Welding, 2014, (1): 18-22.

[3] Yan Jiuchun, Yang Chunli, Liu Huijie, Cui Wei, Xie Weifeng, Guo Weibing. Research status and scientific issues of ultrasonic hybrid welding. Chinese Journal of Mechanical Engineering, 2015.

[4] JC Yan, ZWXu, LShi, XMa, SQ Yang. Ultrasonic assisted fabrication of particle reinforced bonds joining aluminum metal matrix composites. Mater Des, 2011, 32:343-347.

[5] JC Yan, HB Xu, L Shi, XH Wang, SQ Yang. Vibration assisted brazing of SiCp/A356composites: microstructure and mechanical behavior. SciTechnolWeldJoin, 2008, 13(8): 760-764.

[6] ZWXu, JCYan, CWang, SQYang.SubstrateoxideunderminingbyaZn-Alloyduringwettingofaluminaareinforced6061Almatrixcomposite.MaterChemPhys,2008,112(3):831-837.

[7] YCLei, HLXue, WXHu, ZZLiu, JCyan. Effect of farcultrasonic vibration on microstructure of joint of plasma arc 'insitu' welding of SiCp/6061Al. SciTechnolWeldJoin, 2011; 16(7):575-80.

[8] ZLi, YZhou, THNorth. Counteraction of particulate segregation during transient liquid-phase bonding of aluminum-based MMC materials. Journal of Materials Science, 1995, 32:5571-5575.

[9] ASuzumura, YJXing. DiffusionbrazingofshortAl2O3Fiber-ReinforcedAluminumComposite.MaterialsTransactions, 1996, 37(5): 1109-1115.

[10] Liu Weihong, Sun Daqian, Sun Dexin, Jia Shusheng. Al2O3P/6061Al Composite Materials Transient Liquid Phase Diffusion Bonding. Journal of Welding, 2007,28(3):57-60.

[11] Zhao Zude, Shu Dayu, Huang Jihua, Hu Chuankai, Kang Feng. Joint Strength and Fracture Properties of Al-Ag-Cu-Ti Reaction Diffusion Welded SiCP/2009Al Composites. Journal of Welding, 2008, 29(11): 100-104.

[12] Niu Jitai, Lu Jinbin, Mu Yunchao, Luo Xiangwei. Brazing analysis of SiCp/ZL101 composite material and Kovar 4J29. Journal of Welding, 2010,31(5):37-40.

[13] Zou Jiasheng, Zhao Qizhang, Chen Zheng. Research on Brazing Technology of SiC Particle Reinforced Aluminum Matrix Composite Materials. Light Alloy Processing Technology, 2004,32(3):48-52.

[14] GF Zhang, JX Zhang, Y Pei, SY Li, DLChai. Joining of Al2O3p/Al composite by transient liquid phase (TLP) bonding and novel process of active-transient liquid phase (A-TLP) bonding. Materials Science and Engineering A, 2008, 488: 146-156.

[15] GF Zhang, W Su, JX Zhang, ASuzumura. Wetting Behavior of a Novel Al-Si-Ti Active Brazing Filler Metal Foilon Aluminum Matrix Composite. Journal of Materials Engineering and Performance, 2013, 22(7): 1982-1994.

[16] GF Zhang, BChen, MZ Jin, JX Zhang. Active-Transient Liquid Phase (A-TLP) Bonding of High Volume Fraction Si C Particle Reinforced A356 Matrix Composite. Materials Transactions, 2015, 56(2): 212-217.

[17] GF Zhang, XJ Liao, BChen, LJ Zhang, JX Zhang.ApproachtoIn-SituProducingReinforcingPhaseWithinanActive-TransientLiquidPhaseBondSeamforAluminumMatrixComposite.MetallurgicalandMaterialsTransactionsA,2015,46(6):2568-2578.

[18] Li Juan, Wang Kehong, Zhang Deku, Xu Jianing. Microstructure and properties of 70vol.% SiCp/ZL101 composite material brazed joint filled with Al-Cu-Si-Ni-Mg. Thermal Processing Technology, 2015,44(19): 183-186.

[19] Wang Peng, Xu Dongxia, Chen Long, Niu Jitai. Research on Vacuum Brazing Process and Wetting Mechanism of High Volume Fraction SiCP/6063Al Composites. Thermal Processing Technology, 2014,43(3):155-160.

Contents of the invention

The object of the present invention is to provide a kind of active brazing filler metal suitable for high volume fraction SiC reinforced cast aluminum matrix composite material (extremely difficult to wet) and preparation method thereof, so as to realize the expected high volume fraction SiC particle reinforced cast aluminum matrix composite material The "medium and low temperature" and "in-situ strengthening active liquid phase diffusion welding" (in-situ strengthening refers to the brazing seam; activity refers to the wettability of the interface).

To achieve the above object, the present invention adopts the following technical solutions:

A medium-temperature active solder suitable for high-volume SiC-strengthened cast aluminum-based composites, for high-volume-fraction aluminum-based composites (70vol. %SiCp/ZL101), the present invention proposes and prepares Mg as the core de-melting element and active element, Mg and Ga content are higher, Mg-Ga-Ti coexists, but the melting point is far lower than the commonly used Al-12Si eutectic The active solder of Al-Mg-Ga-Ti system, wherein the mass ratio of each element is: 10-30% of Mg, 10-20% of Ga, 0.1-3% of Ti, and the balance is Al. The film removal reaction of high Mg at the M/M interface does not depend too much on the swelling and cracking of the oxide film, and is suitable for high volume fraction aluminum-based composites with "small thermal expansion coefficient" and difficult cracking of the oxide film on the substrate; Mg can also be combined with ZL101 substrate And Si in SiC strengthening phase may react to form Mg ₂ Si phase. High gallium is conducive to the rapid softening of the solder and reduces the solidus of the active solder. It is suitable for high volume fraction aluminum-based composite materials with "high hardness and creep strength", which can make the solder and base metal bond earlier and more quickly. Large-scale contact, closure, and oxygen isolation promote the early low-temperature stage reaction. On the one hand, the addition of Ti is to induce and strengthen the reactive wetting of the particle/brazing filler metal (P/M) interface at the high temperature stage at the ceramic particle interface, and on the other hand, to form a Ti-containing, high-melting point in the brazing joint. , discretely distributed, and fine intermetallic compounds are used as in-situ strengthening phases, and it is also beneficial to bear the initial pressure and prevent the primary liquid phase from being extruded prematurely when the solidus decreases; the coexistence of Mg-Ga improves the early low-temperature section M /M interface wetting; Mg-Ga-Ti coexists and takes into account the P/M interface wetting reaction in the low temperature and high temperature sections.

The Al-Mg-Ga-Ti active solder is preferably Al-24Mg-16Ga-1Ti solder, which is composed of the following components according to the mass fraction: 24% of Mg, 16% of Ga, 1% of Ti , the balance being Al.

The melting range of the Al-24Mg-16Ga-1Ti solder is 383-497°C

The above-mentioned preparation method of active solder suitable for high volume fraction SiC reinforced cast aluminum matrix composites comprises the following steps:

Mix block pure Al, liquid Ga and block Al-5Ti master alloy and put them into the crucible, then under the protection of flowing argon (Ar), heat the crucible from room temperature to 750-800°C and start to keep it warm. After 10-30 minutes, add block-shaped pure Mg, and then continue to keep warm for 10-30 minutes. After the heat preservation, stop the argon protection when it is naturally cooled to 150-200°C, and then continue to cool naturally to room temperature to obtain a smelted block, which is the smelted block. Said Al-Mg-Ga-Ti active solder.

The heating adopts high-frequency induction heating.

The method also includes the following steps: forming the smelted block through rapid cooling and spinning to obtain a solder foil strip.

In terms of brazing technology, the Al-Mg-Ga-Ti active solder adopts the process conditions of solder micro-melting and higher pressure to obtain high-strength joints; wherein, micro-melting means that the brazing temperature is slightly higher than (only 2-10°C higher) The melting point of the active solder (take Al-24Mg-16Ga-1Ti solder as an example, that is, 2-10°C higher than 497°C), the purpose is to prevent the low temperature in the case of high volume fraction SiC The solidus liquid solder is extruded prematurely before it reacts and wets with the composite material; the higher pressure refers to the brazing pressure of 1-1.5MPa, and the purpose of using higher pressure is high volume fraction composite material The creep strength is high, and the application of high pressure is conducive to the earlier and wider contact and reaction between the base metal and the Ti-containing high-Mg active solder with the help of Ga, and is also conducive to preventing the continuous intrusion of air and shortening the isothermal temperature. Freezing time.

The brazing temperature is preferably 480-510°C.

The brazing process specifically refers to in-situ enhanced active liquid phase diffusion welding.

Another kind of active solder suitable for cast aluminum-based composite materials strengthened by high volume fraction SiC, the active solder is Al-Mg-Ti active solder, and the Al-Mg-Ti active solder is based on mass fraction It consists of the following components: 10-30% of Mg, 0.1-3% of Ti, and the balance of Al.

The present invention has the following innovative points:

1) On the one hand, this series of solders removes the film through Mg and Ga demelting elements (also active elements), which improves the wettability of the interface between the metal matrix and the solder metal (M/M), and through Mg, Ga, Ti Triple active elements almost completely eliminate the interface gap between ceramic particles and solder metal (P/M), and improve the wettability of the P/M interface, among which Ga has excellent low-temperature wettability, and can perfectly and continuously wet even at 450°C Wet large-size SiC (length up to 100 μm), and Ti mainly plays the role of wetting silicon carbide at high temperature; on the other hand, fine Al-Mg-Ga-Ti quaternary intermetallic compounds are discretely crystallized in the brazing seam, In this way, the in-situ strengthening of the solid solution type brazing seam matrix obtained by isothermal solidification is realized. The microhardness of the brazing seam is Hv80, which is Hv20 higher than that of the matrix, and the strength of the brazing seam is significantly strengthened.

2) The melting point (383℃～497℃) of Al-24Mg-16Ga-1Ti active solder is lower than the solidus temperature of ZL101 (557℃), far lower than the common Al-Si and Al-Si-Mg solders The melting point (above 577°C) is suitable for brazing of ZL101 base metal. Obviously, the reduction of the solidus (lower than the Al-Mg eutectic 450°C and the Al-Cu-Si ternary eutectic 525°C) is due to the addition of gallium (Ga), which is the rapid softening of the solder and the The initial large-scale contact on the surface of the composite material base material, and the subsequent diffusion and reaction of the active element Mg create favorable conditions. The more active elements contained in the brazing filler metal, the stricter the protection of the brazing filler metal is required, and the lower melting point and rapid softening after adding Ga are equivalent to the high volume fraction composite material interface with hard texture, large elastic modulus, and high creep strength. A soft intermediate layer is pre-set between them, which is very beneficial to increasing the number of close-bonded micro-regions, the degree of closeness, preventing the oxidation of the aforementioned close-fitting regions, and closing the gaps to prevent oxidation.

3) The brazing temperature is set at a medium temperature (about 500°C), that is, the solder is welded in a slightly molten or nearly semi-solid state, and pressure is allowed without solder extrusion; at the same time, avoid higher temperatures (such as 550°C ) The ZL101 matrix is excessively dissolved, and the Si entering the liquid phase will lead to the coarsening of the in-situ strengthening phase (Al-Ti-Si phase containing Si) in the brazing joint.

4) Excellent interfacial wetting, even for high volume fraction 70vol.% SiCp/ZL101, even at 450°C, large-sized SiC particles (up to 100 μm) can be completely wetted; ZL101 matrix can be dissolved at the same time.

5) Under the condition of 500℃×1.5MPa×30min, the average joint shear strength is 118.6MPa, which is 98.8% of the base metal shear strength (120MPa). It is worth pointing out that the shear strength is as high as 2 to 3 times that of other reported Mg-containing brazing joints (about 40-60 MPa).

In a word, the present invention is for the commonly used high volume fraction 70vol.% SiCp/ZL101 composite material, in order to further obtain higher shear strength under medium and low brazing temperature, based on the "in situ strengthened active liquid phase diffusion welding" proposed by the applicant (InsituA-TLP)" idea, "using reactive wetting to improve the wettability of the P/M interface" and "using rising melting elements to obtain in-situ strengthening of the brazing joint", developed a new Al-Mg-Ga -Ti-based active brazing filler metal, which not only improves the wettability of the P/M interface (even at a lower temperature of 450°C), but also obtains an in-situ strengthening phase in the brazing joint, and the effective coefficient of joint strength is as high as 98% of the base metal, The improvement effect is outstanding and stable, which proves the remarkable superiority of this series of solders. It is worth pointing out that the shear strength of the joint obtained by brazing 70vol.% SiCp/ZL101 composite material with the Al-24Mg-16Ga-1Ti brazing material provided by the present invention is as high as that of other various Mg-containing solder brazing joints reported at present. 2 to 3 times the shear strength (about 40~60MPa[16,18]); for the base material of high volume fraction aluminum matrix composite (70vol.%SiCp/ZL101), if a higher brazing temperature is allowed , can use Al-24Mg-1Ti based solder.

Description of drawings

Figure 1 shows the DSC curves of Al-24Mg-16Ga-1Ti(a) and Al-24Mg-1Ti(b) active solder strips: the solidus and liquidus of the former are much lower than the reported addition of Mg, Ni improved solder;

Figure 2(a) is a photo of the microstructure of Al-24Mg-1Ti solder foil on the wettability of 70vol.% SiCp/ZL101 aluminum matrix composite material (550℃×30min; flowing Ar): P/M interface part has been wetted Wet, some are not wetted, but the wetted part also reflects a certain beneficial effect of Mg-Ti; Figure 2(b) is the enlargement of area A in Figure 2(a), and Figure 2(c) is Figure 2( b) Enlargement of the dotted frame area in Figure 2(d) is the enlargement of B area in Figure 2(a), Figure 2(e) is the enlargement of the dotted frame area in Figure 2(d);

Figure 3(a) is the microstructure photo of Al-24Mg-16Ga-1Ti solder foil on the wettability of 70vol.% SiCp/ZL101 aluminum matrix composite material (550℃×30min; flowing Ar): P/M interface Nearly fully wetted; Figure 3(b) is the enlargement of the area A in Figure 3(a), Figure 3(c) is the enlargement of the dotted box area in Figure 3(b), and Figure 3(d) is the enlargement of Figure 3(a) ), and Figure 3(e) is the enlargement of the dotted box area in Figure 3(d);

Figure 4(a) is the photo of the microstructure of the joint obtained by using the Al-24Mg-1Ti intermediate layer (base material: 70vol.% SiCp/ZL101; 500℃×30min×1MPa; flowing Ar): there is a gap at the P/M interface, But it also reflects a certain role of Mg-Ti; Figure 4(b) is an enlargement of the dotted box area in Figure 4(a);

Figure 5a is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 450°C, 1MPa pressure, heat preservation for 30min, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Figure 5b is an enlargement (3000×) of the dotted frame part in Figure 5a;

Figure 5c is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 500°C, 1MPa pressure, heat preservation for 30min, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Figure 5d is an enlargement (3000×) of the dotted box part in Figure 5c;

Figure 5e is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 500 ° C, 1.25 MPa pressure, heat preservation for 30 min, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Figure 5f is an enlargement (3000×) of the dotted box part in Figure 5e;

Figure 5g is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 500 ° C, 1.5 MPa pressure, heat preservation for 30 minutes, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Figure 5h is the magnification (3000×) of the dotted box in Figure 5g: the interface wetting is optimal; and a finely dispersed Al-Mg-Ga-Ti strengthening phase is formed in situ in the solid solutionized brazing joint matrix;

Figure 5i is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 500 ° C, 1.75 MPa pressure, heat preservation for 30 min, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Fig. 5j is the magnification (3000×) of the dotted frame in Fig. 5i: there are many large-sized massive Al ₃ Ti phase segregation in the fracture;

Figure 5k is a schematic diagram of the influence of brazing temperature and pressure on the joint structure (1000×, welding temperature 550 ° C, 1 MPa pressure, heat preservation for 30 min, Ar protection, the middle layer is Al-24Mg-16Ga-1Ti);

Figure 5l is the enlargement (3000×) of the dotted frame in Figure 5k: 8-10 μm striped Al-Si-Ti phase segregation appears;

The base metal in Figures 5a to 5k is 70vol.% SiCp/ZL101; the lower interface can be densely wetted at 500℃×30min×1.5MPa, and dotted in-situ strengthening phases are formed in the solid-solutionized brazing joint matrix (see Figure 5g, Figure 5h);

Figure 6 is a schematic diagram of the effect of Al-24Mg-16Ga-1Ti solder under the condition of 500 ° C × 30min × 1.5MPa "brazing joint in-situ strengthening" (the brazing joint is as high as Hv80, which is nearly 1 times higher than the base metal matrix);

Figure 7 is a comparison chart of the shear strength of Al-24Mg-16Ga-1Ti, Ga-free Al-24Mg-1Ti, and Ti-free Al-24Mg-16Ga solder joints: it proves that Al-24Mg containing Mg, Ga and Ti at the same time -The superiority of 16Ga-1Ti solder;

Figure 8 is the temperature-shear strength (a) and pressure-shear strength (b) variation curves of Al-24Mg-16Ga-1Ti solder foil ribbon welding 70vol.% SiCp/ZL101 composite material joint: at 500 ° C × 30min × Under the condition of 1.5MPa, the shear strength of the joint is as high as 118MPa, which is 98% of the base metal, which proves the outstanding advantages of medium temperature and high strength;

Figure 9(a) is a schematic diagram of the fracture path of Al-24Mg-16Ga-1Ti brazing foil ribbon welding 70vol.% SiCp/ZL101 composite material joint (can be extended into the composite material base material, indicating that on the one hand, the ceramic interface can also be well wetted , even with a high volume fraction of the base metal, on the other hand the brazing joint is strengthened so that the fracture path can enter the interior of the composite base metal); Fig. 9(b) is an enlargement of the area A in Fig. 9(a), and Fig. ) is the enlargement of the dotted box area in Figure 9(b), Figure 9(d) is the enlargement of the B area in Figure 9(a), and Figure 9(e) is the enlargement of the dotted box area in Figure 9(d).

detailed description

The invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

The invention discloses a low-melting-point Al-Mg-Ga-Ti-based quaternary active brazing filler metal having three active elements of the melting-down type (Ga, Mg) and the melting-up type (Ti), which realizes "in-situ strengthening" Active liquid phase diffusion welding". This series of brazing filler metals removes the film by Mg and Ga demelting elements (also active elements) to improve the low-temperature wettability of the metal substrate and the brazing filler metal interface; eliminates the gap between the ceramic particles and the brazing filler metal interface through the triple active elements of Mg, Ga, and Ti, Improve P/M interface wettability, where Ga has low-temperature wettability, and can perfectly and continuously wet large-size SiC even at 450°C; at the same time, fine Al-Mg-Ga-Ti intermetallic compounds are discretely crystallized in the brazing joint , The microhardness of the brazing seam is Hv82, which is nearly 1 times higher than that of the matrix, and the brazing seam is strengthened in situ.

The present invention aims at the high volume fraction of the ceramic reinforcing phase (70vol.% SiCp/ZL101 composite material) not only directly causes the P/M interface to be difficult to wet, but also indirectly leads to the special difficulty that the M/M interface is also difficult to wet. Higher shear strength is obtained at a lower brazing temperature, following the "in-situ strengthening active liquid phase diffusion welding" proposed by the applicant (the in-situ strengthening in this term is for the braze itself; the activity is for In terms of interface wettability), further optimize the demelting elements (improving the wettability of the M/M interface), the active elements (improving the wettability of the P/M interface) and the rising elements (strengthening the weld) to Preparation of active alloy interlayer.

Aiming at the common problem of low shear strength (only 40-60MPa) of brazing filler metals added with Mg and Ni in existing reports, an active brazing filler metal based on Al-Mg-Ga-Ti alloy was proposed. The role of Mg and Ga is to ensure the wettability of the M/M interface in the early low temperature section; Mg, Ga, and Ti are added together to improve the wettability of the P/M interface, and Ga can play a role in wetting SiC at the low temperature section , and Ti mainly plays the role of wetting SiC at high temperature; at the same time, the in-situ crystallized Ti-containing high-melting point phase can be used to realize the in-situ strengthening effect on the brazing joint matrix that has become a solid solution after isothermal solidification; through the above improvement M The wettability of the /M and P/M interfaces and the in-situ strengthening of the brazing joints are obtained at the same time, forcing the fracture path to enter the composite base material, which greatly improves the shear strength of the joints. The present invention can rely on the aluminum matrix composite base material (70vol.% SiCp/ZL101 composite material) reinforced by high volume fraction SiC without any complicated auxiliary technology (such as brazing flux, scraping, vibration, gasket) By optimizing the solder composition design, a high-strength joint (98.8%) with a shear strength (118MPa) very close to that of the base metal was obtained.

Compared with the classic demelting elements Cu, Si, Zn, Mg is expected to play an active role in M/M and P/M. The reason is that for the P/M interface, Mg can improve the wettability of the P/M interface by reacting with SiC to form Mg ₂ Si; The swelling and cracking of the oxide film is suitable for high volume fraction aluminum-based composite materials with a small expansion coefficient; it can also react and crystallize with Si in the ZL101 matrix to form Mg ₂ Si) and physical mechanism (underflow under the film) to remove it evenly film (compared to Zn), improving the wettability of the M/M interface. Therefore, for the high-volume-fraction Al-matrix composite base material that is difficult to wet even the M/M interface, Mg is the first choice as the core de-melting element in the optimization of de-melting elements, in order to improve M/M and P/M at the same time. Wettability of the M interface. Considering that the Mg-containing solder must increase the pressure to prevent oxidation and promote contact with the surface of the base metal (especially in the case of high Mg), so although the solder may react with the oxide film on the surface of the base metal in the solid state, the Mg-containing solder The hardness of the material itself hinders its earlier and wider contact and reaction with the surface of the base metal, so gallium, which has a very low melting point and does not embrittle Al (Ga is easy to make the solder heat and soften quickly; and greatly reduces the brazing temperature. The solidus line of the material, increasing the distance between the solidus line and the liquidus line), is the earlier and wider contact between the active elements Mg and Ti and the surface of the base metal (including the stage when the solder is still in a solid state), and the interface is closed Create favorable conditions for isolation of air and interfacial reaction (in addition, the applicant is currently proving that Ga can also react with SiC, thereby improving the wettability of the P/M interface through a chemical mechanism); at the same time, considering the large volume fraction of the ceramic phase, the P/M If the proportion of the interface is large, the Mg content will be increased together with a larger welding pressure, which will create favorable conditions for earlier and wider contact and reaction between Mg and the surface of the base metal from the other side. Based on the analysis of the above scheme, the applicant designed an Al-Mg-Ga-Ti active solder with high content of Mg and Ga, coexistence of Mg-Ga-Ti, but low melting point according to the ternary alloy phase diagram. The mass ratio is: 10-30% Mg, 10-20% Ga, 0.1-3% Ti, and the rest is Al.

For the high volume fraction aluminum matrix composites that are difficult to wet even the metal matrix/metal solder (M/M) interface, in this series of active solders, Mg is used as the core de-melting element, and high Mg is at the M/M interface The film removal reaction does not depend too much on the swelling and cracking of the oxide film, and is suitable for the base material of aluminum matrix composite materials with high volume fraction; high gallium is conducive to the rapid softening of the solder, reducing the solidus line, and can make the solder and the base metal more Early and wider closure, oxygen barrier, contact, and reaction; on the one hand, the addition of Ti is to induce and strengthen the reactive wetting of the particle/brazing filler metal (P/M) interface at the high temperature stage at the ceramic particle interface, and on the other hand On the one hand, in order to form Ti-containing, high melting point, discretely distributed, and fine intermetallic compounds in the brazing joint as in-situ strengthening phases, it is also beneficial to withstand the initial pressure and prevent the initial liquid phase when the solidus decreases. Get squeezed out prematurely.

In terms of brazing process, the process conditions of micro-melting of solder and higher pressure are used to obtain high-strength joints. Among them, slight melting means that the brazing temperature is slightly higher (only a few degrees higher) than the melting point of the active solder. Premature extrusion; at the same time, avoid excessive temperature so that excessive Si in the matrix dissolves into the liquid solder, resulting in the formation of an in-situ strengthening phase (Al-Ti-Si phase) that is too coarse. The purpose of using higher pressure is that the high volume fraction composite material has high creep resistance, and the application of high pressure is beneficial to the earlier and wider contact and reaction between such base metal and Ti-containing high-Mg active solder with the help of Ga. , is also beneficial to shorten the isothermal solidification time. It should be pointed out that just because of the excellent wettability of the Al-Mg-Ga-Ti active solder (such as Al-24Mg-16Ga-1TGi) provided by the present invention, it can allow the use of high pressure conditions (otherwise it will be squeezed out) out).

Example 1

In this instance, the preparation method of Al-24Mg-16Ga-1Ti series quaternary active solder for aluminum-based composite material may further comprise the steps:

1) material selection

The selected raw materials are: block pure Al, block pure Mg, liquid 99.99% Ga, block Al-5Ti master alloy.

2) Ingredients and loading

The proportion of ingredients is 24% Mg, 16% Ga, 1% Ti, and the rest is Al. Mix 12 grams of block pure Al, 4.8 grams of liquid Ga and 6 grams of block Al-5Ti master alloy in a corundum crucible (glass tubes cannot be used).

3) Smelting

Under the protection of flowing Ar, use high-frequency induction heating to heat the ingredients in the crucible from room temperature to 750-800°C and start to keep warm. After keeping warm for 10 minutes, add 7.2 grams of Mg immediately, and then continue to keep warm for 20 minutes. After the heat preservation is completed, cool to 200 Close the gas at ℃, and then lower to room temperature to obtain a smelted block.

4) Strip molding

After the smelted block obtained in step 3) is remelted, a foil strip is made by adopting a rapid cooling strip stripping process.

Example 2

In this example, as contrast solder, the preparation of similar solder Al-24Mg-1Ti system ternary active solder comprises the following steps:

1) material selection

The selected raw materials are: block pure Al, block pure Mg, block Al-5Ti master alloy.

2) Ingredients and loading

The proportion of ingredients is 24% Mg, 1% Ti, and the rest is Al. 16.8 grams of block pure Al and 6 grams of block Al-5Ti master alloy were mixed together in a corundum crucible.

3) Smelting

Under the protection of flowing Ar, use high-frequency induction heating to heat the ingredients in the crucible from room temperature to 750-800°C and start to keep warm. After keeping warm for 10 minutes, immediately add 7.2 grams of Mg with corresponding content, and then continue keeping warm for 20 minutes. Cool to 200°C and turn off the gas, then lower to room temperature to obtain a smelted block.

4) Strip molding

After the smelted block obtained in step 3) is remelted, a foil strip is made by adopting a rapid cooling strip stripping process.

Implementation method of melting point test: The melting point of the Al-Mg-Ga-Ti active solder foil strip was actually measured by differential scanning calorimetry (DSC: Differential scanning calorimeter). As shown in Figure 1(a) and Figure 1(b), the melting range of Al-24Mg-16Ga-1Ti solder foil is 383-497°C, and the melting range of Al-24Mg-1Ti solder foil is 446-446℃. 537°C. Comparing the melting range of the two solders, it can be found that the melting point of Al-24Mg-16Ga-1Ti solder is significantly lower than that of Al-24Mg-1Ti solder foil, and 16wt.% Ga can reduce the melting point of solder by about 40-60 ° C. It can be used as a demelting element (MPD); and the liquidus temperature is lower than the solidus temperature (557°C) of the composite material matrix (ZL101), suitable for brazing.

Wettability test implementation method: the base material is 70vol.% SiCp/ZL101 aluminum-based composite material, and the sample size is 15mm×15mm×3mm. Before welding, the base metal is polished with 240# diamond grinding disc, 600# diamond grinding disc, and 600# water sandpaper in sequence, and then the solder foil strip (size 7mm×5mm×0.15mm) and the ground base metal are both in acetone Perform 10min ultrasonic cleaning. The wetting experiment adopts high-frequency induction to heat the tubular steel cavity wall. The sample and solder are placed inside the steel cavity, protected by 5L/min Ar gas, the holding temperature is set at 550°C, and the holding time is 30 minutes. The wetting behavior of Al-24Mg-1Ti solder on 70vol.%SiCp/ZL101 aluminum matrix composite material is shown in Figure 2(a)~(e). It can be found from the low-magnification images that the interface between the metal solder and the base metal Very dense, in the case of high magnification, part of the SiC surface is very densely wetted (this is mainly due to the reactive wetting of SiC by active Ti), but it can also be clearly found that there are even 30 μm continuous gaps, and some SiC particle surfaces are not wetted at all. In contrast, it can be clearly found from Figure 3(a)~(e) that Al-24Mg-16Ga-1Ti solder has very good wettability to 70vol.% SiCp/ZL101 aluminum matrix composite material, not only M/M The interface is dense, and the P/M interface is also very dense without obvious gaps or holes. This is mainly due to the double wetting effect of Ga and Ti on SiC, which greatly improves the wettability of the P/M interface. However, Mg2Si phases are found in the residual solder and base metal matrix in Figure 2(a)～(e) and Figure 3(a)～(e), indicating that Si in the base metal matrix dissolves into the solder, and the Mg in the solder It also diffuses into the matrix of the base material, so as to achieve the effect of removing the film and improving the M/M interface. The above results show that the wettability of Al-24Mg-16Ga-1Ti solder to 70vol.% SiCp/ZL101 aluminum matrix composite is better than that of Al-24Mg-1Ti solder.

Brazing experiment implementation method: the base material is 70vol.% SiCp/ZL101 aluminum matrix composite material, the sample size of the upper plate is 7.5mm×7.5mm×3mm, and the sample size of the lower plate is 15mm×15mm×3mm. Before welding, The base metal was polished sequentially with 240# diamond grinding disc, 600# diamond grinding disc, and 600# water sandpaper, and then the solder foil (size 9mm×9mm×0.15mm) and the polished base metal were subjected to 10min ultrasonic in acetone cleaning. The welding experiment uses high-frequency induction coil heating, 5L/min Ar gas protection, and the holding time is 30min.

See Figure 4(a) and Figure 4(b) for the joint structure of the Al-24Mg-1Ti intermediate layer at 500 °C and 1 MPa pressure. It can be seen from the figure that the M/M interface and part of the P/M interface are very dense, but There are also some gaps and holes in some P/M interfaces, which affect the performance of the joint. Therefore, in view of its high melting point and poor interface, it is not the most preferred solder solution.

The microstructure of the joint using the Al-24Mg-16Ga-1Ti intermediate layer under different welding parameters is shown in Figure 5a to Figure 5l. It can be seen from the figure that at 450 ° C × 1 MPa, the M/M and P/M interfaces are very dense. And there is a white transition layer with a thickness of about 0.5 μm around SiC, which shows that Ga does play a role in reactively wetting SiC (only Ti and Ga with high atomic numbers can form a bright layer, and the measured Ti content Ga is very little, and Ga is more, indicating that Ga plays a beneficial role in the wetting of the P/M interface); and a coarse white network phase with high Mg content is found in the brazing joint, which is a brittle intermetallic compound, which greatly deteriorates the the joint strength. As the welding temperature increases to 550 °C, it can be clearly found that there are segregated strengthening phases and IMC/SiC interfaces belonging to the weak bonding zone inside the brazing joint, and these two defects will be the source of cracks in the fracture process. However, at an appropriate welding temperature of 500°C (only 3°C higher than the solder liquidus) and a pressure of 1 MPa, it can be clearly found that there is no coarse white network phase with high Mg content in the brazing seam, and the brazing seam matrix becomes a solid solution, and There is no segregation phenomenon in the dispersed distribution of the fine strengthening phase, and this improvement strengthens the performance of the joint. However, there are gaps in part of the P/M interface that need to be eliminated urgently, so the applicant continues to increase the pressure at 500°C. In the case of 500°C×1.5MPa, the entire M/M and P/M interface is very dense, and the brazing seam Medium-discrete crystallization produces fine and dispersed point-like phases (about Al-2.0Mg-1.0Ga-0.4Ti(at.%)), the size is about 0.2-0.8μm, and the microhardness of the brazing joint is Hv82 (see figure 6), Hv40 is higher than that of the matrix, which significantly strengthens the strength of the weld, and can play the role of in-situ strengthening of the braze. However, when the welding pressure increased to 1.75MPa, there was a large gap at the P/M interface and a large Al ₃ Ti phase was formed in the joint, which greatly deteriorated the joint performance.

The shear strength comparison of Al-24Mg-16Ga-1Ti, Ga-free Al-24Mg-1Ti, and Ti-free Al-24Mg-16Ga solder joints is shown in Figure 7, which proves that Al-24Mg-16Ga- The superiority of 1Ti solder. Therefore, the Al-24Mg-16Ga-1Ti solder can be selected as the key research object. The role of Mg and Ga is to ensure the wettability of the M/M interface. Mg, Ga, and Ti are added together to improve the wettability of the P/M interface. Wettability, in which Ga can play the role of wetting silicon carbide at low temperature, and Ti will work at high temperature to improve the wettability of the high temperature section.

For the optimized Al-24Mg-16Ga-1Ti intermediate layer, the effect of welding conditions (temperature and pressure) on the shear strength of the joint obtained by brazing 70vol.% SiCp/ZL101 is shown in Figure 8(a), Figure 8( b). Under the optimal condition of 500℃×1.5MPa, the joint strength is the highest, up to 119.3MPa. In order to verify the repeatability, according to the same implementation method, welding multiple samples, the average shear strength of the joint under this condition can be measured as high as 118.6MPa, accounting for about 98.8% of the strength of the base metal (the shear strength of the base metal is about 120MPa) , demonstrating that the joint strength dispersion is small. For different temperatures, under the pressure of 1MPa, the joint strength is the highest when the welding temperature is 500°C, and its average shear strength can reach 90.6MPa, accounting for about 75.5% of the base metal strength (the base metal shear strength is about 120MPa). If the temperature is too high (550°C), the strength of the joint will decrease instead, because the segregated Al-Si-Ti phase in the brazing seam weakens the performance of the interface and the brazing seam. Above-mentioned welding test proves that the advantage of the Al-24Mg-16Ga-1Ti quaternary active solder that the present invention provides is: (1) brazing temperature is lower (500 ℃); (2) joint shear strength is high (118MPa, 98% of the base material); (3) stable performance and good repeatability.

The fracture paths of the Al-24Mg-16Ga-1Ti interlayer under the optimized welding conditions of 500°C×1.5MPa are shown in Figure 9(a)-(e). It can be seen from the figure that, except for a small part of the fracture along the metal solder/base metal interface, most of the fracture path can extend to the inside of the base metal (mostly along the base metal matrix, and a small part breaks through the SiC particles in the base metal), indicating that the interface Both the strength of the joint and the brazing joint are high enough to force the fracture path into the interior of the composite base metal. This fracture path behavior is consistent with the joint strength results.

In summary, the Al-Mg-Ga-Ti system quaternary active solder proposed in the present invention has successfully realized the "medium and low temperature" and "in-situ strengthening active liquid phase" expected for high volume fraction SiC particle reinforced cast aluminum matrix composites. Diffusion welding" (in-situ strengthening refers to the braze; active refers to the wettability of the interface). The advantages of this brazing material are as follows: (1) In terms of activated wettability: on the one hand, the wettability of the M/M interface is improved by removing the film of Mg and Ga demelting elements; on the other hand, the triple active elements of Mg, Ga, and Ti Completely eliminate the P/M gap and improve the wettability of the P/M interface. Ga has low temperature wettability, and can eliminate the P/M (even large-sized SiC particles up to 100 microns) interface gap at a lower temperature of 450 °C , Improve P/M interface wettability. (2) In terms of brazing joint strengthening, fine strengthening phases of dispersed Al-2.5Mg-1.5Ga-0.3Ti (at.%) were successfully obtained, realizing in-situ strengthening of solid solution-based brazing joints. The composition characteristics of the in-situ strengthening phase are "micro-Ti and no Si", indicating that due to the temperature characteristics of medium-temperature welding, the dissolution of the base metal matrix is limited (different from the underflow film removal mechanism under the traditional TLP film), and the chemical film removal mechanism of Mg and Ga played a role that cannot be ignored. (3) The performance of the joint has been greatly improved: Brazing 70vol.% SiCp/ZL101 at 500℃×1.5MPa×30min, the shear strength is 2 to 3 times that of other solders, 98.8% of the base metal, and the fracture path It extends to the inside of the base metal, and very few parts break along the interface between the base metal and the solder. (4) Low brazing temperature: good wetting and diffusion can be obtained at 500°C, and the brazing seam matrix can become a solid solution (Al-1.3Mg-0.8Ga). (5) Solve the melting and adding of high melting point element Ti in the process of solder preparation. Therefore, it is very suitable for medium temperature brazing (about 500 ° C) high volume fraction SiC particle reinforced cast aluminum matrix composites.

Claims (9)

1. An active solder material suitable for high-volume fraction SiC reinforced cast aluminum-based composite materials, characterized in that: the active solder material is an Al-Mg-Ga-Ti system active solder material, and the Al-Mg-Ga - The Ti-based active solder is composed of the following components according to the mass fraction: 10-30% of Mg, 10-20% of Ga, 0.1-3% of Ti, and the balance of Al. 2. The active solder suitable for cast aluminum-based composites reinforced with high volume fraction SiC according to claim 1, characterized in that: said Al-Mg-Ga-Ti active solder is preferably Al-24Mg-16Ga - 1 Ti solder, which is composed of the following components according to the mass fraction: 24% Mg, 16% Ga, 1% Ti, and the balance is Al. 3. The active solder suitable for casting aluminum-based composite materials strengthened by high volume fraction SiC according to claim 2, characterized in that: the melting range of the Al-24Mg-16Ga-1Ti solder is 383-497°C . 4. the active solder suitable for high volume fraction SiC reinforced cast aluminum matrix composites according to claim 1, characterized in that: the brazing process parameters of the Al-Mg-Ga-Ti system active solder include : The brazing temperature is 2-10° C. higher than the melting point of the Al-Mg-Ga-Ti-based active solder, and the brazing pressure is 1-1.5 MPa. 5 . The active solder suitable for high volume fraction SiC reinforced cast aluminum matrix composites according to claim 4 , characterized in that the brazing temperature is 480-510° C. 5 . 6 . The active solder suitable for high volume fraction SiC reinforced cast aluminum matrix composites according to claim 4 , wherein the brazing process specifically refers to in-situ enhanced active liquid phase diffusion welding. 7 . 7. A method for preparing an active solder material suitable for high volume fraction SiC reinforced cast aluminum matrix composites as claimed in claim 1, characterized in that: comprising the following steps: Mix block pure Al, liquid Ga and block Al-5Ti master alloy and add them into the crucible, then under the protection of flowing argon, heat the crucible to 750-800°C and start to keep warm, wait for 10-30 minutes before adding Block pure Mg, then continue to keep warm for 10-30 minutes, stop the argon protection when it is naturally cooled to 150-200°C after the heat preservation, and then continue to cool naturally to room temperature to obtain a smelted block, which is the Al-Mg- Ga-Ti active solder. 8 . The method according to claim 7 , characterized in that: the method further comprises the following step: forming the smelted block by spinning to obtain a solder foil strip. 9. An active solder suitable for cast aluminum-based composite materials reinforced by high volume fraction SiC, characterized in that: the active solder is an Al-Mg-Ti active solder, and the Al-Mg-Ti active solder is The brazing material is composed of the following components according to the mass fraction: 10-30% of Mg, 0.1-3% of Ti, and the balance of Al.