Alloy brazing filler metal of brazing-flux-free brazing foamed aluminum core veneer and preparation method thereof

Abstract

The invention discloses an alloy brazing filler metal of a brazing-flux-free brazing foamed aluminum core veneer and a preparation method of the alloy brazing filler metal, wherein the alloy brazing filler metal is an alloy material whose range of melting point is from 450 DEG C to 600 DEG C. Elements of Cu and Mg are added in an aluminum-silicon-based brazing flux to prepare the alloy material with better flowability and appropriate melting point as a brazing filler metal, the alloy brazing filler metal is good in flowability and low in melting point, the elements of Cu and Mg in a brazing filler metal body are dispersed towards a solid phase foamed aluminum end in the welding process and are wetted and spread out on the surface of a base metal to implement the connection of parts, no brazing flux is used in a matched way in the welding process, no vacuum or protection atmosphere condition is needed, a compact oxidation film is removed by using a mechanical / physical method in a matched way, and a compact welding line is formed during the welding to implement the high-strength welding of the foamed aluminum.

Description

technical field [0001] The invention relates to the field of foamed aluminum material processing, in particular to an alloy brazing filler metal for soldering a foamed aluminum core plate without flux and a preparation method thereof. Background technique [0002] Foamed aluminum material is a high-tech new material developed in recent years. It has many excellent properties such as sound absorption, sound insulation, heat insulation, electromagnetic shielding, vibration damping and buffering, etc. Toxicity, odorless, corrosion resistance, anti-aging and other properties. [0003] Due to the use of a small amount of metal to realize the multi-functionalization of structural materials, it has opened up new ways to solve existing problems in many high-tech fields. cutting-edge hot materials. At present, the research on aluminum foam abroad is more in-depth, and it has been successfully applied to the fields of automobiles, construction, packaging, machine tools and so on. ...

AI Technical Summary

Problems solved by technology

In addition, the dense oxide film in the pore structure of aluminum foam during brazing is also an important factor leading to poor welding performance. The existence of the oxide layer hinders the combination of the base metal and the solder. The traditional method of removing the aluminum oxide film is to use fluoride Immersion in flux molten salt, corrosion damages the dense oxide film, must be cleaned and heated after immersion brazing to remove corrosive residual salt, but for the porous structure of aluminum foam core board, cleaning is difficult, resulting in Severe Corrosion of Foam Aluminum Core Board

[0006] In terms of solder selection, when tin-based and zinc-based brazing with a low melting point, the surface of the foamed aluminum core is composed of thinner cell edges and cell walls, and the tensile and shear strength of the welded joints are relatively low

Aluminum-silicon-based solder with a high melting point can easily cause a large amount of collapse of the foamed aluminum pore structure, resulting in difficulty in forming the molten pool and weld or poor fusion

In addition, after treatment with flux such as fluoride, it is not easy to clean due to the porous structure of the foamed aluminum core, resulting in severe corrosion of the foamed aluminum core board.

The existing brazing methods and solders of foamed aluminum have many problems in joint corrosion resistance, fatigue resistance, weld formation and joint mechanical properties, which greatly limit the preparation of large-scale foamed aluminum sandwich panels and the production of foamed aluminum sandwich panels. In the application of high-tech and civilian fields, it is of great significance to study the solder suitable for the flux-free brazing of the foamed aluminum core porous structure.