A method for improving the welding strength of pure nickel strip and aluminum strip used in electronic industry

Abstract

The invention discloses a method for improving the welding strength of pure nickel strips and aluminum strips used in the electronics industry. Firstly, metal copper is deposited on the surface of pure nickel strips by using a magnetron sputtering physical vapor deposition method, and then deposited on the surface of pure nickel strips. Copper is used as the transition metal of the welding interface, and the nickel strip and the aluminum strip are welded under the protection of inert gas by laser welding. The welding method of the present invention not only ensures good electrical conductivity of the material, does not affect the mechanical properties of the welded joint, but also avoids excessive welding brittle phases on the welding surface, low shaping and poor toughness, and is easy to crack after welding. problem, achieved a unique microstructure control, high welding strength, and an increase of 30 N in interfacial tensile strength.

Description

technical field [0001] The invention relates to the technical field of welding pure nickel strips and aluminum strips used in the electronics industry, and more specifically relates to a method for improving the welding strength of pure nickel strips and aluminum strips used in the electronics industry. Background technique [0002] Pure metal nickel strip has high strength, good electrical conductivity and processing ductility, and is widely used in aerospace, electronics, marine, machinery manufacturing and other fields. The production of high-quality metal strip includes important processes such as pure smelting, hot rolling, cold rolling, and annealing. The cold rolling process can ensure the mechanical properties of the product, and through the proper cooperation of cold rolling deformation and heat treatment process, special Strips with textured grain structure include nickel strips and aluminum strips. For example, some special textures can improve the conductivity of...

AI Technical Summary

Problems solved by technology

However, there are usually the following problems in the welding of aluminum strips and nickel strips: (1) due to the low thermal conductivity and large resistivity of pure nickel metal, problems such as thermal cracks, pores, and coarse grains are prone to occur during welding. When the parameters are not good or the parameters do not match, more inclusions or harmful phases will be precipitated in the heat-affected zone, causing micro-cracks to initiate at the weld, seriously reducing the mechanical properties of the welded joint after welding, and affecting the use of the workpiece; (2) During the welding process of pure nickel strip and aluminum strip, if there is a small amount of oxygen (O) in the weld, O and Ni will form nickel oxide, and nickel oxide can further form a eutectic phase with a low melting point with nickel, and the eutectic phase is in the crystal After cooling, under the action of high welding residual stress, it will cause microcracks in the weld seam and heat-affected zone, which will significantly reduce the strength of the welded joint; (3) The main chemical composition of the domestic pure nickel strip is shown in Table 1 It is shown that there are usually some trace elements (such as Mg, Si, S, C, etc.) in nickel strips, these trace elements will widen the solidification range of metallic nickel, and produce various brittle precipitates in the grain and grain boundary, which are easy to initiate Solidification cracks bring difficulties to the welding of nickel strips and aluminum strips. The test results show that nickel has a high chemical affinity to the elements sulfur (S) and phosphorus (P), and two low-melting eutectic phases NiS2- Ni and Ni3P-Ni, and distributed in the grain boundary, reduce the bonding strength of the weld

However, during the laser welding process of nickel strips and aluminum strips, there are many influencing factors, including the contact surface being in an atmospheric atmosphere, and the proportion of metal element content is difficult to accurately control, etc., making it difficult to controllably form welded joints with good plastic toughness and high strength. High beneficial phase, so that the strength of welded joints is low

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