阅读说明：本技术 钎料合金、钎料及其制备方法和应用以及制得的钎焊产品 (Brazing alloy, brazing filler metal, preparation method and application of brazing filler metal and prepared brazing product ) 是由 杜全斌 张肇伟 范九红 李伟 刘春鹏 王星星 于 2020-05-18 设计创作，主要内容包括：本发明提供了一种钎料合金、钎料及其制备方法和应用以及制得的钎焊产品,涉及焊接材料技术领域。上述钎料合金在传统Zn-Al基钎料基础上,通过添加Mg、Ni、Cr、Ga和稀土元素以特定组分配比制备得到。其中,上述钎料合金中Ni可提高钎料强度；Mg可提高钎料的电极电位；Cr可形成致密氧化膜降低腐蚀速率；Ga可提高腐蚀产物的粘附性,使其均匀覆盖在钎料表面上,减小钎料裸露面积；稀土元素可细化晶粒和净化界面,降低晶间腐蚀倾向。本发明通过上述组分之间的合理配比,能够实现协同增效的作用,在提高钎料的钎焊强度的同时,又保证钎料具有良好的耐腐蚀性,能够充分满足现有铝-铜材料钎焊连接的工艺需要。(The invention provides a brazing alloy, a brazing filler metal, a preparation method and application of the brazing filler metal and a prepared brazing product, and relates to the technical field of welding materials. The brazing filler metal alloy is prepared by adding Mg, Ni, Cr, Ga and rare earth elements according to a specific component proportion on the basis of the traditional Zn-Al-based brazing filler metal. Wherein, Ni in the brazing alloy can improve the strength of the brazing alloy; mg can improve the electrode potential of the brazing filler metal; cr can form a compact oxide film to reduce the corrosion rate; ga can improve the adhesiveness of corrosion products, so that the corrosion products can be uniformly covered on the surface of the brazing filler metal, and the exposed area of the brazing filler metal is reduced; the rare earth elements can refine crystal grains and purify interfaces, and reduce the intergranular corrosion tendency. According to the invention, through reasonable proportioning of the components, the synergistic effect can be realized, the brazing strength of the brazing filler metal is improved, the brazing filler metal is ensured to have good corrosion resistance, and the process requirements of the existing aluminum-copper material brazing connection can be fully met.)

1. The brazing filler metal alloy is characterized by being prepared from the following components in percentage by mass:

3-25 wt% of Al, 0.1-5.5 wt% of Mg, 0.01-1.5 wt% of Ni, 0.05-3 wt% of Cr, 0.1-1.5 wt% of Ga, 0.01-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%.

2. Solder alloy according to claim 1, characterized in that the solder alloy is mainly prepared from the following components in mass percent:

9-22 wt% of Al, 1-3 wt% of Mg, 0.5-1.5 wt% of Ni, 0.3-1.5 wt% of Cr, 0.5-1.5 wt% of Ga, 0.2-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%.

3. Solder alloy according to claim 1, characterized in that the solder alloy is mainly prepared from the following components in mass percent:

9 wt% of Al, 2 wt% of Mg, 1 wt% of Ni, 0.5 wt% of Cr, 1 wt% of Ga, 0.5 wt% of rare earth elements and 86 wt% of Zn86 wt.

4. A solder alloy according to any one of claims 1 to 3, wherein the solder alloy comprises Al, Ni, Cr and Mg in percentages by mass which satisfy the following relationship: [ Al ] is more than or equal to 1.37[ Ni ] +3.63[ Cr ] +1.69[ Mg ];

preferably, the rare earth elements comprise at least one of cerium, lanthanum, praseodymium, neodymium, yttrium and scandium;

preferably, the solder alloy further comprises impurity elements, and the mass percentage of the impurity elements in the solder alloy is 0-0.03 wt%.

5. A method of making a solder alloy according to any of claims 1 to 4, comprising the steps of:

providing a mixture containing the components in the formula amount, and then alloying the mixture to obtain a solder alloy;

preferably, the preparation method comprises the following steps:

(A) mixing and alloying Mg, Ni, Cr, Ga and rare earth elements with the formula amount and partial amount of Al respectively to form AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy;

(B) and (C) mixing and alloying the residual Al, Zn with the formula amount and the AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy obtained in the step (A) to obtain the brazing filler metal alloy.

6. The method for preparing the brazing filler metal alloy according to claim 5, wherein the content of Mg in the AlMg alloy in the step (A) is 10-20 wt%, preferably 15 wt%;

preferably, the Ni content in the AlNi alloy in the step (A) is 5-20 wt%, preferably 10 wt%;

preferably, the content of Cr in the AlCr alloy in the step (A) is 4-6 wt%, preferably 5 wt%;

preferably, the content of the rare earth element in the Al-rare earth alloy in the step (A) is 10-16 wt%, and preferably 12 wt%;

preferably, the Ga content in the AlGa alloy of the step (A) is 22-40 wt%, preferably 30 wt%;

preferably, the method for alloying each raw material in the step (B) comprises the following steps:

(a) mixing and smelting the rest Al, AlNi alloy and AlCr alloy at 780-860 ℃ to obtain alloy liquid A;

(b) cooling to 700-710 ℃, and mixing and smelting the alloy liquid A and Zn according to the formula amount to obtain alloy liquid B;

(c) cooling to 685-695 ℃, and mixing and smelting the alloy liquid B, the AlGa alloy, the AlMg alloy and the Al-rare earth alloy in sequence to obtain alloy liquid C;

(d) sequentially refining, casting and solid dissolving the alloy liquid C to obtain a solder alloy;

more preferably, the refining method in the step (d) is a gas-solvent composite refining method;

more preferably, the casting in the step (d) is to cast the refined alloy liquid into a round ingot with the diameter of 60-100 mm, and preferably the diameter is 80 mm;

more preferably, the temperature for solid solution in the step (d) is 300-400 ℃, and preferably 360 ℃;

more preferably, the time for solid solution in the step (d) is 10-24 h, and preferably 12 h.

7. A brazing filler metal, characterized in that the brazing filler metal is mainly prepared from the brazing filler metal alloy of any one of claims 1 to 4;

preferably, the diameter of the brazing filler metal is 0.8-3.0 mm.

8. A method for preparing the brazing filler metal according to claim 7, wherein the method comprises the following steps:

sequentially carrying out hot extrusion and drawing on the brazing filler metal alloy according to any one of claims 1 to 4 to obtain a brazing filler metal;

preferably, the preparation method further comprises the step of carrying out surface passivation treatment on the solder after being drawn.

9. Use of a solder alloy as claimed in any one of claims 1 to 4, a solder as claimed in claim 7 in the manufacture of a soldered product.

10. A brazed product, characterized in that it is mainly prepared from the brazing filler metal of claim 7.

Technical Field

The invention relates to the technical field of welding materials, in particular to a brazing alloy, a brazing filler metal, a preparation method and application of the brazing filler metal and a prepared brazing product.

Background

In refrigeration, power, electronics and other industries, in order to achieve the purposes of light structure and cost saving, aluminum materials are often used to replace copper materials. However, due to the difference in certain properties between aluminum and copper, some important structural components must be made of copper, and therefore, there is a corresponding technical problem of aluminum-copper connection during the manufacturing process of some components.

At present, the connection method of aluminum-copper mainly comprises fusion welding, pressure welding, brazing and the like. Wherein, the strength of the fusion welding joint is low, and the fusion welding joint is not suitable for aluminum-copper connection; the pressure welding joint has the best quality, but the equipment is expensive, the production cost is high, and the pressure welding joint is not suitable for flow line production; the brazing method has the advantages of better welding quality than fusion welding, low cost and high production efficiency, and is suitable for flow line production, so the brazing method is a first-push connection mode of the existing aluminum-copper material connection.

The existing brazing filler metal for aluminum-copper brazing mainly comprises Al-Si-based brazing filler metal, Sn-Zn-based brazing filler metal and Zn-Al-based brazing filler metal. Wherein: the brazing temperature of the Al-Si based brazing filler metal is high, the aluminum base metal is easily melted during brazing, and a large amount of CuAl is easily generated during brazing aluminum-copper₂And Cu₃Al₂Intermetallic compounds, resulting in low joint strength; the Sn-Zn-based solder has low brazing temperature, is used for aluminum-copper soldering, has the shear strength of a brazed joint of more than 40MPa, but has poor corrosion resistance, and can fall off after being soaked in water or saline water for 1 to 4 weeks; compared with Sn-Zn base and Al-Si base solders, the melting temperature of the Zn-Al base solder is lower than that of the Al-Si base solder, the price is low, and the Zn-Al base solder is the preferred solder for soldering aluminum-copper dissimilar metals.

However, the existing commercially available Zn-Al-based brazing filler metal generally has the problems of low brazing strength, the shearing strength of only 30-40 MPa, poor corrosion resistance, easy occurrence of aging and embrittlement phenomena in the storage process, serious influence on the brazing manufacturability of the brazing filler metal and the mechanical property of joints, and incapability of ensuring the reliability of the joints.

Therefore, it becomes necessary and urgent to develop a Zn-Al based solder alloy with high soldering strength and strong corrosion resistance, and further satisfy the requirements of soldering process performance and joint mechanical properties of the existing aluminum-copper material soldering connection.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide a brazing alloy which is prepared by compositely adding Mg, Ni, Cr, Ga and rare earth elements according to a specific component proportion on the basis of a traditional Zn-Al-based brazing filler metal.

The second purpose of the invention is to provide a preparation method of the brazing filler metal alloy, which has the advantages of short process flow, simple equipment and easy operation, and can realize large-scale industrial production of the brazing filler metal alloy.

The third purpose of the invention is to provide a brazing filler metal, which is mainly prepared from the brazing filler metal alloy and has the advantages of high brazing strength and strong corrosion resistance.

The fourth purpose of the invention is to provide a preparation method of the brazing filler metal, which has the advantages of simple preparation process and easy realization.

A fifth object of the present invention is to provide a use of the above solder alloy or solder for producing a soldered product.

A sixth object of the present invention is to provide a brazed product.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a brazing alloy which is mainly prepared from the following components in percentage by mass:

3-25 wt% of Al, 0.1-5.5 wt% of Mg, 0.01-1.5 wt% of Ni, 0.05-3 wt% of Cr, 0.1-1.5 wt% of Ga, 0.01-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%.

Further, the brazing filler metal alloy is mainly prepared from the following components in percentage by mass:

9-22 wt% of Al, 1-3 wt% of Mg, 0.5-1.5 wt% of Ni, 0.3-1.5 wt% of Cr, 0.5-1.5 wt% of Ga, 0.2-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%.

Further, the brazing filler metal alloy is mainly prepared from the following components in percentage by mass:

9 wt% of Al, 2 wt% of Mg, 1 wt% of Ni, 0.5 wt% of Cr, 1 wt% of Ga, 0.5 wt% of rare earth elements and 86 wt% of Zn86 wt.

Further, the mass percentages of Al, Ni, Cr and Mg in the brazing alloy satisfy the following relations: [ Al ] is more than or equal to 1.37[ Ni ] +3.63[ Cr ] +1.69[ Mg ];

preferably, the rare earth elements comprise at least one of cerium, lanthanum, praseodymium, neodymium, yttrium and scandium;

preferably, the solder alloy further comprises impurity elements, and the mass percentage of the impurity elements in the solder alloy is 0-0.03 wt%.

The invention provides a preparation method of the brazing filler metal alloy, which comprises the following steps:

providing a mixture containing the components in the formula amount, and then alloying the mixture to obtain a solder alloy;

preferably, the preparation method comprises the following steps:

(A) mixing and alloying Mg, Ni, Cr, Ga and rare earth elements with the formula amount and partial amount of Al respectively to form AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy;

(B) and (C) mixing and alloying the residual Al, Zn with the formula amount and the AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy obtained in the step (A) to obtain the brazing filler metal alloy.

Further, the content of Mg in the AlMg alloy in the step (A) is 10-20 wt%, preferably 15 wt%;

preferably, the Ni content in the AlNi alloy in the step (A) is 5-20 wt%, preferably 10 wt%;

preferably, the content of Cr in the AlCr alloy in the step (A) is 4-6 wt%, preferably 5 wt%;

preferably, the content of the rare earth element in the Al-rare earth alloy in the step (A) is 10-16 wt%, and preferably 12 wt%;

preferably, the Ga content in the AlGa alloy of the step (A) is 22-40 wt%, preferably 30 wt%;

preferably, the method for alloying each raw material in the step (B) comprises the following steps:

(a) mixing and smelting the rest Al, AlNi alloy and AlCr alloy at 780-860 ℃ to obtain alloy liquid A;

(b) cooling to 700-710 ℃, and mixing and smelting the alloy liquid A and Zn according to the formula amount to obtain alloy liquid B;

(c) cooling to 685-695 ℃, and mixing and smelting the alloy liquid B, the AlGa alloy, the AlMg alloy and the Al-rare earth alloy in sequence to obtain alloy liquid C;

(d) sequentially refining, casting and solid dissolving the alloy liquid C to obtain a solder alloy;

more preferably, the refining method in the step (d) is a gas-solvent composite refining method;

more preferably, the casting in the step (d) is to cast the refined alloy liquid into a round ingot with the diameter of 60-100 mm, and preferably the diameter is 80 mm;

more preferably, the temperature for solid solution in the step (d) is 300-400 ℃, and preferably 360 ℃;

more preferably, the time for solid solution in the step (d) is 10-24 h, and preferably 12 h.

The brazing filler metal provided by the invention is mainly prepared from the brazing filler metal alloy;

preferably, the diameter of the brazing filler metal is 0.8-3.0 mm.

The invention provides a preparation method of the brazing filler metal, which comprises the following steps:

sequentially carrying out hot extrusion and drawing on the brazing filler metal alloy to obtain brazing filler metal;

preferably, the preparation method further comprises the step of carrying out surface passivation treatment on the solder after being drawn.

The invention provides the brazing alloy and the application of the brazing alloy in preparing brazing products.

The brazing product is mainly prepared from the brazing filler metal.

Compared with the prior art, the invention has the beneficial effects that:

the brazing filler metal alloy provided by the invention is prepared by compositely adding Mg, Ni, Cr, Ga and rare earth elements according to a specific component proportion on the basis of the traditional Zn-Al-based brazing filler metal. Wherein, Ni in the solder alloy can improve the strength of the solder; mg can improve the electrode potential of the brazing filler metal; cr can form a compact oxide film, so that the corrosion rate is reduced; ga can improve the adhesiveness of corrosion products, uniformly cover the surface of the brazing filler metal, reduce the exposed area of the brazing filler metal and prevent the brazing filler metal from corroding; the rare earth elements can refine crystal grains and purify interfaces, and reduce the intergranular corrosion tendency. According to the invention, the components are reasonably proportioned, so that the synergistic effect can be realized, and compared with the traditional Zn-Al-based brazing filler metal, the brazing strength of the brazing filler metal is improved, and the brazing filler metal is ensured to have good corrosion resistance. The detection proves that the brazing filler metal alloy can fully meet the requirements of the brazing process performance and the joint mechanical property of the existing aluminum-copper material brazing connection.

The preparation method of the brazing alloy provided by the invention comprises the steps of firstly providing a mixture containing the components in the formula amount, and then alloying the mixture to prepare the brazing alloy.

The brazing filler metal provided by the invention is mainly prepared from the brazing filler metal alloy, has the advantages of high brazing strength and strong corrosion resistance, and can fully meet the requirements of the brazing process performance and the joint mechanical property of the existing aluminum-copper material brazing connection.

According to the preparation method of the brazing filler metal, provided by the invention, the brazing filler metal alloy is subjected to hot extrusion and drawing in sequence to obtain the brazing filler metal. The preparation method has the advantages of simple preparation process and easy realization.

The brazing alloy or the brazing filler metal provided by the invention can be widely applied to the preparation process of brazed products.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to one aspect of the invention, the brazing filler metal alloy is mainly prepared from the following components in percentage by mass:

3-25 wt% of Al, 0.1-5.5 wt% of Mg, 0.01-1.5 wt% of Ni, 0.05-3 wt% of Cr, 0.1-1.5 wt% of Ga, 0.01-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%.

The brazing filler metal alloy provided by the invention is prepared by compositely adding Mg, Ni, Cr, Ga and rare earth elements according to a specific component proportion on the basis of the traditional Zn-Al-based brazing filler metal. Wherein, Ni in the solder alloy can improve the strength of the solder; mg can improve the electrode potential of the brazing filler metal; cr can form a compact oxide film, so that the corrosion rate is reduced; ga can improve the adhesiveness of corrosion products, uniformly cover the surface of the brazing filler metal, reduce the exposed area of the brazing filler metal and prevent the brazing filler metal from corroding; the rare earth elements can refine crystal grains and purify interfaces, and reduce the intergranular corrosion tendency. The invention can realize the synergistic effect by reasonable proportioning of the components, and compared with the traditional Zn-Al-based brazing filler metal, the invention improves the brazing strength of the brazing filler metal, ensures that the brazing filler metal has good corrosion resistance, and can fully meet the requirements of the brazing process performance and the joint mechanical property of the existing aluminum-copper material brazing connection.

Typical but non-limiting preferred embodiments of the above-mentioned Al are: 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 22% and 25%; typical but non-limiting preferred embodiments of the above Mg are: 0.1%, 0.5%, 1%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, and 5.5%; typical but non-limiting preferred embodiments of the above-mentioned Ni are: 0.01%, 0.1%, 0.5%, 0.8%, 1.0%, 1.2%, and 1.5%; typical but non-limiting preferred embodiments of the above Cr are: 0.05%, 0.1%, 0.3%, 0.5%, 1.5%, 2%, 2.5% and 3%; typical but non-limiting preferred embodiments of the above Ga are: 0.1%, 0.5%, 0.8%, 1.0% and 1.5%; typical but non-limiting preferred embodiments of the above rare earth elements are: 0.01%, 0.2%, 0.5%, 0.6%, 0.7% and 1%.

The invention takes Zn expressed by 'balance' as an essential component to overcome the problem that the percentage range of each component in the brazing filler metal alloy is less than 100%, and the 'balance' can also comprise other optional components besides the components, as long as the sum of the percentage contents of each component in the brazing filler metal alloy is 100%.

In a preferred embodiment of the present invention, the solder alloy is mainly prepared from the following components in percentage by mass:

9-22 wt% of Al, 1-3 wt% of Mg, 0.5-1.5 wt% of Ni, 0.3-1.5 wt% of Cr, 0.5-1.5 wt% of Ga, 0.2-1 wt% of rare earth elements and the balance of Zn, wherein the sum of the mass percentages of the components is 100 wt%;

in the above preferred embodiment, the solder alloy is mainly prepared from the following components in percentage by mass:

9 wt% of Al, 2 wt% of Mg, 1 wt% of Ni, 0.5 wt% of Cr, 1 wt% of Ga, 0.5 wt% of rare earth elements and 86 wt% of Zn86 wt.

In a preferred embodiment of the present invention, the mass percentages of Al, Ni, Cr and Mg elements in the solder alloy satisfy the following relationship: [ Al ] > 1.37[ Ni ] +3.63[ Cr ] +1.69[ Mg ].

In a preferred embodiment of the present invention, the rare earth element includes at least one of cerium, lanthanum, praseodymium, neodymium, yttrium, scandium;

in a preferred embodiment, the rare earth element can refine grains and purify interfaces, the refined grains can improve uniformity of grain boundary distribution, reduce electrochemical potential difference between intragranular and grain boundaries, and purify the grain boundaries to further reduce the electrochemical potential difference between intragranular and grain boundaries, thereby reducing intergranular corrosion tendency.

In a preferred embodiment of the invention, the solder alloy further comprises impurity elements, and the mass percentage of the impurity elements in the solder alloy is 0-0.03 wt%.

In a preferred embodiment, the above-mentioned solder alloy contains an impurity element inevitably, but the mass percentage of the impurity element in the solder alloy should not exceed 0.03 wt%.

According to an aspect of the present invention, a method for preparing the above solder alloy comprises the steps of:

providing a mixture containing the components in the formula amount, and then alloying the mixture to obtain a solder alloy;

the preparation method of the brazing alloy provided by the invention comprises the steps of firstly providing a mixture containing the components in the formula amount, and then alloying the mixture to prepare the brazing alloy.

In a preferred embodiment of the present invention, the preparation method comprises the steps of:

(A) mixing and alloying Mg, Ni, Cr, Ga and rare earth elements with a part of Al according to the formula amount respectively to form AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy respectively;

(B) and (C) mixing and alloying the residual Al, Zn with the formula amount and the AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy obtained in the step (A) to obtain the brazing filler metal alloy.

The amount of Al forming part of the AlMg alloy, AlNi alloy, AlCr alloy, algal alloy and Al-rare earth alloy in the above step (a) is added to the amount of Al remaining in the step (b) and is the total amount of Al in the brazing filler metal alloy preparation composition of the present invention.

In a preferred embodiment, in the step (a), Mg, Ni, Cr, Ga and rare earth elements in the amounts specified in the formula are mixed with a part of Al and alloyed to prepare an intermediate alloy in advance, whereby the uniformity of the brazing material can be improved and the temperature for melting the brazing material can be reduced.

In a preferred embodiment of the present invention, the content of Mg in the AlMg alloy of step (a) is 10 to 20 wt%, preferably 15 wt%;

in a preferred embodiment, the melting temperature of the AlMg alloy is reduced as much as possible, but the Mg content is too high, which tends to increase the Mg burnout during the melting process.

In a preferred embodiment of the present invention, the Ni content in the AlNi alloy of step (a) is 5 to 20 wt%, preferably 10 wt%;

as a preferred embodiment, the eutectic composition of the AlNi alloy is AlNi5.7, the Ni content is 5-20 wt%, and within the composition range, the melting temperature of the AlNi alloy is lower than 800 ℃, so that the melting temperature can be reduced to the maximum extent, the burning loss can be reduced, and the cost can be saved. The Ni content is preferably 10 wt%, which is beneficial to preparing the zinc-aluminum solder with lower Ni content on one hand, and the AlNi10 alloy has lower melting temperature and moderate strength plasticity on the other hand.

In a preferred embodiment of the present invention, the content of Cr in the AlCr alloy of step (a) is 4 to 6 wt%, preferably 5 wt%;

as a preferred embodiment, the Cr content in the AlCr alloy of step (a) above facilitates the formulation of higher Ni content solders, but increasing the Cr content will significantly increase the melting temperature of the AlCr alloy.

In a preferred embodiment of the present invention, the Ga content of the AlGa alloy of step (A) is 22 to 40 wt%, preferably 30 wt%;

as a preferred embodiment, the melting temperature of the AlGa alloy is reduced as much as possible, but too high Ga content is not favorable for preparing the zinc-aluminum solder with lower Ga content.

In a preferred embodiment of the present invention, the method for alloying each raw material in the step (B) comprises the steps of:

(a) mixing and smelting the rest Al, AlNi alloy and AlCr alloy at 780-860 ℃ to obtain alloy liquid A;

(b) cooling to 700-710 ℃, and mixing and smelting the alloy liquid A and Zn according to the formula amount to obtain alloy liquid B;

(c) cooling to 685-695 ℃, and mixing and smelting the alloy liquid B, the AlGa alloy, the AlMg alloy and the Al-rare earth alloy in sequence to obtain alloy liquid C;

(d) sequentially refining, casting and solid dissolving the alloy liquid C to obtain a solder alloy;

as a preferred embodiment, the reason why the alloying of each raw material in the step (B) is performed is that: zn, Mg and rare earth elements are volatile elements, are easy to burn in the smelting process, and the burning loss amount can be reduced by reducing the smelting temperature; al (about 660 ℃), AlNi alloy (below 800 ℃) and AlCr alloy (below 840 ℃) have higher melting temperature, so that the Al, the AlNi and the AlCr are melted firstly; the Zn content is high, the melting point is 419 ℃, and the temperature can be reduced and melted properly; the contents of AlGa alloy, AlMg alloy and Al-rare earth alloy are low, the melting temperature of AlGa alloy is lower than 650 ℃, the melting temperature of AlMg alloy is lower than 610 ℃, and the melting temperature of Al-rare earth alloy is lower than 660 ℃, so that the melting temperature can be further reduced, and the burning loss of alloy elements can be reduced.

In the above preferred embodiment, the refining method in the step (d) is a gas-solvent composite refining method;

the specific method of the gas-solvent composite refining method comprises the following steps: by Ar₂Transporting CaF₂、ZnCl₂Mixing the powder, adding the mixed powder into an alloy solution, stirring the alloy solution, and removing the non-metallic impurities and hydrogen.

In the preferred embodiment, the casting in the step (d) is to cast the refined alloy liquid into a round ingot with a diameter of 60-100 mm, preferably 80 mm;

in the preferred embodiment, the solid solution temperature in the step (d) is 300-400 ℃, preferably 360 ℃;

in the above preferred embodiment, the time for solid solution in the step (d) is 10 to 24 hours, preferably 12 hours.

According to one aspect of the present invention, a brazing filler metal is mainly prepared from the above brazing filler metal alloy;

the brazing filler metal provided by the invention is mainly prepared from the brazing filler metal alloy, has the advantages of high brazing strength and strong corrosion resistance, and can fully meet the requirements of the brazing process performance and the joint mechanical property of the existing aluminum-copper material brazing connection.

In the preferred embodiment, the diameter of the brazing filler metal is 0.8 to 3.0 mm.

According to an aspect of the present invention, a preparation method of the above brazing filler metal comprises the steps of:

sequentially carrying out hot extrusion and drawing on the brazing filler metal alloy to obtain brazing filler metal;

according to the preparation method of the brazing filler metal, provided by the invention, the brazing filler metal alloy is subjected to hot extrusion and drawing in sequence to obtain the brazing filler metal. The preparation method has the advantages of simple preparation process and easy realization.

In the above preferred embodiment, the production method further includes a step of performing surface passivation treatment on the solder after the drawing;

preferably, the surface passivation treatment comprises surface degreasing, cleaning, surface polishing, cleaning and surface passivation, wherein the surface degreasing adopts alkaline solution for chemical degreasing, and the solution formula is Na₂CO₃(10～30g/L)、Na₃PO₄(10-30 g/L), the temperature is 75-85 ℃, and the oil removing time is 2-10 min. The surface polishing is chemical polishing, and the formula of the solution is CrO₃(200～300g/L)、HNO₃(20～30mL/L)、 H₂SO₄(3-10 mL/L) and alkyl sulfate (0.5-3 g/L), the temperature is 20-40 ℃, and the time is 0.5-3 min. Chemical passivation formula CrO₃(100～200g/L)、BaCO₃(1-5 g/L), the temperature is 20-40 ℃, and the time is 5-30 s.

Preferably, the preparation method of the brazing filler metal comprises the following steps:

(1) mixing and alloying Mg, Ni, Cr, Ga and rare earth elements with a part of Al according to the formula amount respectively to form AlMg alloy, AlNi alloy, AlCr alloy, AlGa alloy and Al-rare earth alloy respectively;

wherein the Mg content in the AlMg alloy is 15 wt%; the Ni content in the AlNi alloy is 10 wt%; the Cr content in the AlCr alloy is 10 wt%; the Ga content in the AlGa alloy is 30 wt%;

(2) preheating a graphite crucible in a resistance furnace, placing the residual Al in the crucible, and then heating the resistance furnace to 725-735 ℃;

(3) after the residual Al is completely melted, adding AlNi alloy and AlCr alloy, heating to 780-860 ℃, and stirring for 3-5 min;

(4) when the temperature of the alloy liquid is reduced to 700-710 ℃, keeping the temperature in the furnace at 700-710 ℃, adding Zn according to the formula amount in three times, wherein the mass parts of Zn added in the three times are 35%, 35% and 30%, respectively, and adding Zn in the second and third times after the Zn added in the last time is melted and stirred for 3-5 min;

(5) cooling the alloy liquid to 685-695 ℃, adding the AlGa alloy, and stirring for 3-5 min after the AlGa alloy is completely melted;

(6) keeping the temperature of the alloy liquid at 685-695 ℃, adding AlMg alloy, pressing the AlMg alloy below the liquid level of the alloy to prevent the AlMg alloy from being lost, and stirring for 3-5 min after the AlMg alloy is completely melted;

(7) keeping the temperature of the alloy liquid at 685-695 ℃, adding the Al-rare earth alloy, and stirring for 3-5 min after the Al-rare earth alloy is completely melted;

(8) keeping the temperature of the alloy liquid at 685-695 ℃, refining the alloy liquid obtained in the step (7) by using a refining agent, standing for 5-10 min, and sampling to detect the chemical components of the alloy;

(9) when the temperature of the alloy liquid is reduced to 520-580 ℃, carrying out slag dragging and casting on the alloy liquid with qualified chemical components in the step (8), and casting into the alloy liquid with the size ofThe round ingot casting;

(10) carrying out solid solution aging on the round ingot in the step (9) at 360 ℃ for 12 h;

(11) removing peel and slag of the round cast ingot subjected to solid solution aging in the step (10), and then sequentially performing hot extrusion and three-time drawing to finally obtain the round cast ingot with the diameter ofThe brazing filler metal of (1).

According to an aspect of the invention, the solder alloy as described above, the use of the solder as described above for the preparation of a brazed product.

The brazing alloy or the brazing filler metal provided by the invention can be widely applied to the preparation process of brazed products.

According to an aspect of the present invention, a brazing product is mainly prepared from the above brazing filler metal.

In the above preferred embodiment, the brazing product comprises a braze joint.

The technical solution of the present invention will be further described with reference to examples and comparative examples.