Friction Stir Joint Technology And Performance Analysis Of Aluminum Alloy/pure Copper Heterometal

The aluminum alloy/pure copper heterogeneous metal-friction stir joint has the characteristics of low material cost and excellent electrical and thermal conductivity.It has been widely used in power generation,chemical,aerospace,transportation and electronics industries.Compared with the traditional fusion welding,brazing,pressure welding,etc.,the aluminum alloy/pure copper heterogeneous metal FSJ is less prone to defects such as pores and cracks,which is beneficial to improve the mechanical properties of the joint.This paper intends to carry out the butt and lap joint experiment of 3mm thick 6061-T6 aluminum alloy and T2 pure copper.Analyze the surface morphology,microstructure and mechanical properties of FSJ joints under different process parameters.The specific research content is as follows:(1)In the 6061-T6 aluminum alloy/T2 pure copper friction stir joint lap experiment,the influence of the position of the plate and the process parameters on the surface morphology of the joint area is studied.Studies have shown that when the copper plate is placed on the upper plate,the aluminum plate is prone to over-melting,and the joint surface is prone to defects.When the aluminum plate is on top,a joint with excellent surface forming can be obtained within a wide range of process parameters.(2)In 6061-T6 aluminum alloy/T2 pure copper friction stir connection butt joint experiment,The effects of three processes of linear trajectory friction stir connection,linear trajectory friction stir connection with auxiliary plate,and auxiliary S-type trajectory friction stir connection on the formability of joints were studied separately,and 6061-T6 aluminum alloy/T2 pure copper was determined.The optimal process of friction stir joint butt joint.(3)The influence of different process parameters on the mechanical properties of friction stir joining lap/butt joints was studied.Studies have shown that the range of process parameters for obtaining lap joints with excellent mechanical properties is wide.When the rotation speed is 700r/min and the welding speed is 150mm/min,the tensile strength of the lap joint reaches the highest 218.5MPa.The process parameter range for obtaining the mechanical properties of the butt joint with excellent mechanical properties is relatively narrow.Only when the spindle speed is 800r/min,the mechanical properties of the joint are relatively excellent,and its tensile strength can reach up to 195.9 MPa.(4)The microstructure of friction stir joint lap/butt joints is studied,and the influence of process parameters on the grains of weld nugget zone of lap joints is analyzed.The results show that as the rotation speed and traveling speed increase,the degree of grain refinement is further improved.The grains in the weld nugget zone of lap/butt joints are small and equiaxed.The grains in the heat-mechanical affected zone are distorted and deformed.The grain morphology of the heat-affected zone is similar to the structure of the base metal,accompanied by a certain degree of coarsening.(5)The XRD and EDS analysis of the friction stir joint lap/butt joints showed that A1 and Cu were only mixed in unequal proportions near the aluminum alloy/pure copper bonding surface.XRD analysis of lap/butt joints showed that no intermetallic compounds were formed at the joints.Figure[46]Table[6]Reference[69]...