Aluminum alloy intermediate temperature solder for braze welding

Abstract

It relates to an aluminum alloy solder with its components' mass percentage 16-20%Cu,5-8%Si,0.2-2.0%Mn,0-2%Mg, and the rest being Al. Small portion of Ti and B fine grains can be added to the solder to improve processing performance. The molten temperature of solder ranges 500-540DEG C, solder welding temperature 540-570DEG C, suitable for aluminum alloy soldering with the solids line temperature below 540DEG C. The solder can be made into different types like blocks, quick condensed strips or bars, suitable for vacuum soldering, protective solder and flame solder. The solder 6A02,2A5 alloy joint has tensile strength bigger than 100MPa, joint shearing force bigger than 80Mpa, without significant reduction of the joint strength after 200h salt fog corrosion.

Description

technical field [0001] The invention relates to an aluminum alloy medium-temperature brazing filler metal, which belongs to the technical field of aluminum alloy welding connection. Background technique [0002] Aluminum alloy has the characteristics of light weight, good corrosion resistance, good thermal conductivity and electrical conductivity. It is more and more widely used in military and civilian industries such as aviation, aerospace, electronics, and automobiles. However, due to the lack of brazing materials with low melting point and good comprehensive performance, the melting point of mature Al-Si series brazing materials is above 577°C, so the brazing of aluminum alloys is still limited to pure aluminum and individual grades such as 3A21 and 6063. However, a large number of aluminum alloys with higher strength levels still cannot be brazed. On the other hand, due to the demand for lightweight products, the demand for brazing of high-strength aluminum alloys is ...

AI Technical Summary

Problems solved by technology

However, due to the lack of brazing materials with low melting point and good comprehensive performance, the melting point of mature Al-Si series brazing materials is above 577°C, so the brazing of aluminum alloys is still limited to pure aluminum and individual grades such as 3A21 and 6063. , a large number of aluminum alloys with higher strength levels still cannot be brazed

On the other hand, due to the demand for lightweight products, the demand for brazing of high-strength aluminum alloys is becoming more and more urgent. Only the brazing of pure aluminum and low-strength aluminum alloys such as 3A21 and 6063 can no longer meet the requirements for structural strength and rigidity. Therefore, the research and development of low-melting-point solder required for high-strength aluminum alloy brazing, and its implementation has become one of the key technologies to be solved urgently in the manufacture of aluminum alloy components.

[0003] At present, alloy systems such as Al-Ge, Al-Ge-Si, Al-Cu-Si, Ag-Al-Cu, and Zn-Al are used in the research of low-temperature brazing filler metals for aluminum alloys, but most of them have poor manufacturability or poor joint quality. Due to technical problems such as poor performance, there is no generally accepted solder with good comprehensive performance.

For example, Al-Ge and Al-Ge-Si solders have poor seam filling process and high cost; Al-Cu-Si based solders have poor corrosion resistance and poor processing technology; Zn-containing solders are not suitable for vacuum brazing each have different disadvantages

In recent years, some people have added nickel, tin and other elements on the basis of Al-Cu-Si system to obtain the effect of lowering the melting point and improving the overall performance of the solder, but each solder has its own shortcomings, such as difficult preparation and poor corrosion resistance. , poor manufacturability, etc., have not been widely used