FSW (Friction Stir Welding) method of nickel-plated aluminum alloy plate doped by rare-earth lanthanum

Abstract

The invention relates to an FSW (Friction Stir Welding) method of a nickel-plated aluminum alloy plate doped by rare-earth lanthanum. According to the FSW method disclosed by the invention, chemical nickel-plated solution containing the rare-earth lanthanum can be firstly prepared, rare-earth element lanthanum (La) exists in a form of an oxide of La, plating can be carried out on the side surfaces of to-be-welded aluminum alloy plates, Ni-La2O3 coating layers of which the thickness is 10 [mu]m-100 [mu]m are obtained on the butt-joint surfaces of the aluminum alloy plates, two aluminum alloy plates containing the coating layers can be then fixedly arranged on the fixing platform in a butt joint way, the two aluminum alloy plates are connected together through FSW, an alloy structure of a welding seam zone can be observed through a scanning electron microscopy after cooling, the increment of Al11La3 phases is found, the Al11La3 phases are dispersely distributed along a crystal boundary, crystal particles are combined more tightly, the crystal particles in the welding seam zone are well refined, inter-crystalline deformation is prevented, the mechanical property of a joint is tested after welding, and a testing result indicates that the toughness, the strength, the plasticity and the corrosion resistance of a connecting zone are all increased.

Description

technical field [0001] The invention relates to a friction stir welding method for nickel-plated aluminum alloy plates doped with rare earth lanthanum, and belongs to the technical field of material connection and surface coating. Background technique [0002] Friction stir welding (FSW) is a new type of green and pollution-free welding method. It was invented by The Welding Institute (TWI) in 1991. The patent number is (US 5460317). It is a new type of solid Phase connection technology, no flux and solder are needed in the welding process, only through the rotation of the stirring head and moving according to the pre-set path, under the action of friction, down pressure and shearing force, a certain amount of heat is generated, so that the stirring head passes The metal material in the heat-affected zone is in a solid solution state (below the melting point), and the heat-affected zone is the area that needs to be connected in the workpiece to be welded. After the friction ...

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Problems solved by technology

[0003] During the butt welding process, since the two plates are of the same material, the metallographic structure change in the heat-affected zone is not obvious after the friction stir welding. The performance of the joint is better than that of ordinary welding, but the tensile strength is only It can reach 60-70% of the base metal, and its corrosion resistance and toughness are worse than that of the base metal

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