Spreading welding method of magnesium alloy and aluminum alloy containing composite middle layer

Abstract

The invention relates to a low temperature high intensity welding method of magnesium alloy and aluminum alloy containing a composite middle layer. The method includes utilizing an aluminum film and a nickel foil to serve as a composite middle layer. The aluminum film is precipitated on the face of magnesium alloy to be welded by magnetron sputtering. The method further includes adopting vacuum spreading welding with the welding temperature as 400-460 DEG C, keeping the temperature for 10-120min and enabling the welding pressure to be 0.1-3MPa. The method has the advantage of utilizing a composite middle layer of the aluminum film and the nickel foil to achieve spreading welding of the magnesium alloy and the aluminum alloy. Addition of the aluminum film layer and the nickel foil changes magnesium / aluminum interface phase composition and microstructure, and avoids generation of compounds between high-hardness fragile magnesium and aluminum at the interface. The shearing strength reaches 26MPa, and the magnetron sputtering aluminum coated film on the face of the magnesium alloy to be welded improves inoxidizability of the face of the oxydic magnesium alloy to be welded and improves structure and performance of products between Mg and Ni. The method is suitable for reliable welding of magnesium alloy and aluminum alloy in different kinds, and is simple in process, high in parallel accuracy and small in welding piece transformation.

Description

technical field [0001] The invention relates to the field of connecting magnesium alloys and aluminum alloys, in particular to a high-strength welding method for magnesium alloys and aluminum alloys. Background technique [0002] Aluminum alloy has been one of the most widely used metal materials in the defense industry. Because aluminum alloy has the characteristics of low density, high strength, and good processing performance, it can be made into profiles, pipes, plates, etc. of various cross-sections. Therefore, aluminum alloy is the preferred lightweight structural material for lightweight components. In the aviation industry, aluminum alloys are mainly used to manufacture aircraft skins, bulkheads and long beams; in the aerospace industry, aluminum alloys are important component materials for launch vehicles and spacecraft. As a rapidly emerging new green engineering structural material, Mg alloys have broad application prospects in aerospace, national defense, automo...

AI Technical Summary

Problems solved by technology

However, due to the differences in physical and chemical properties of magnesium-aluminum dissimilar metals, it is very difficult to achieve reliable connection by general welding methods. The main problems in the direct welding of the two metals are: (1) Magnesium has a large thermal brittleness and is very reactive. High, easy to react with oxygen in the air to form an inert oxide film on the surface, the existence of oxide film is not conducive to the mutual diffusion of base metal atoms; (2) Magnesium and aluminum are easy to react with each other, and a large amount of High hardness brittle intermetallic compounds and delamination, resulting in weak welded joints

Studies have shown that Mg-Al dissimilar metal welding can be achieved by adding a single Zn, Ag, etc. as an intermediate layer welding, but the diffusion welding method of Mg-Al dissimilar metals by designing a composite intermediate layer has not been reported

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