Method for improving quality of Al-Cu dissimilar metal friction stir welding butt joint

Abstract

The invention discloses a method for improving the quality of an Al-Cu dissimilar metal friction stir welding butt joint. The method specifically comprises the steps that the edges of butt-joint sidesof an aluminum welding part and a copper welding part used for welding are firstly machined into engaged sawtooth sides, then the welding parts on the two sides are in butt joint along the sawtooth sides, and then friction stir welding is carried out. The treatment method is simple, only simple machining is needed, and cost is low; welding seam forming of Al-Cu dissimilar metal friction stir welding can be obviously improved, and the metal mixing degree and the plastic flow behavior of Al-Cu dissimilar metal in the welding process are improved; and meanwhile, the area of an Al-Cu welding interface is increased, the bearing capacity of the joint is increased, the distribution state of a brittle IMC along the interface is changed, and the mechanical performance of the joint is obviously improved.

Description

technical field [0001] The invention belongs to the field of friction stir welding of heterogeneous metals, and in particular relates to a method for improving the quality of friction stir welding butt joints of Al-Cu heterogeneous metals. Background technique [0002] FSW technology is a solid phase welding technology invented by the British Welding Institute (TWI) in 1991. FSW shows great advantages in addition to welding aluminum alloys, magnesium alloys, copper alloys, titanium alloys, etc., and has greater advantages in welding dissimilar metals than other methods. Al-Cu heterogeneous welded joints have broad application prospects in the fields of power electronics and automotive engineering, but there are still great technical problems in Al-Cu welding that have not been resolved, such as poor welding formation and serious sticking of aluminum by the stirring head during welding As a result, the welding process cannot continue, the joint strength is low and there is b...

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Problems solved by technology

[0003] At present, in order to improve the welding quality of Al-Cu dissimilar metal FSW joints, researchers at home and abroad have carried out a lot of research work, and studied the following process methods, such as: adding barrier layers [Liu H J, Shen J J, Xie S, et al. Weldappearance and microstructural characteristics of friction stir butt barrierwelded joints of aluminum alloy to copper[J].Science and Technology ofWelding and Joining,2013,17(2):104-110.], follow-up rolling after welding to improve structure[CN 106181020A ], copper side plus external heat source [Zhao Pengcheng et al. Effect of external heat source on aluminum-copper friction stir welding [J]. Journal of Welding Society, 2017,38(6):69-72.], double-pass friction stir welding[ Jin Yuhua et al. Forming and interface structure of Cu-Al joint after double-pass friction stir welding[J]. Journal of Lanzhou University of Technology, 2017,43(4):28-32.], Stirring head offset[ I, Loureiro A, Verdera D, et al.Influence of Tool Offsetting on the Structure and Morphology of Dissimilar Aluminum to Copper Friction-Stir Welds[J].Metallurgical&Materials Transactions A,2012,43(13):5096-5105.] The welding quality of friction stir welded joints of Al-Cu dissimilar metals has not been significantly improved, especially the mechanical properties of the joints have not been significantly improved

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