The Research Of Friction Stir Welding Lap Joint For Dissimilar Metals Of Aluminium Alloy To Copper

Al-Cu composite-joint has become the focus of attention in modern engineering application.It isdifficult to obtain the high quality welding joint by the traditional welding method.The research offriction stir welding lap process with2mm6061aluminum alloy to copper in this paper.Processinglap welding with copper or aluminum as upper plate respectively. Adjust the welding processparameters to obtain good quality welding joint welding parameter window with the research of Weldsurface morphology、microstructure and microhardness at Cross section、mechanical properties.Finding the welding process parameters window of aluminum alloy as the upper plate is more widecompare with the copper for upper plate. And the maximum shear force of composite-joint is103.06MPa, compareing with copper plate for upper plate has great improvement. Because the maximumshear force of the joint with copper plate for upper plate is94.16MPa. It is known that the fracture ismixed fracture mode from the fracture morphology.The relationship between banding self-locked macroscopic structure and several differentinterface “Interactive organization” structure with the change of welding heat input was investigated.Indicate the basic rule of interfacial behavior of the dissimilar Al-Cu lap joints.And these localorganization structure are to improve the combine property of the dissimilar Al-Cu FSW lap welds.When the copper plate as the upper plate, it has formed some brittle intermetallic compound atthe Al-Cu joint interface through the cross section XRD analysis. The study found that unit time, unitweld length of the heat input increase, eutectic reaction easy to come up at the interface, GeneratingAl-CuAl₂eutectics organization. With the decrease of the heat input, the degree and range of theeutectic reaction reduced.Other words, the heat input reduction can inhibit the occurrence of eutecticreaction.Combined with single pass welding experiment results.Effect of the Double pass welding ofAdvancing side to Advancing side and Retreating side to Retreating side with different offset in thisexperiment was investigated.Finding out the offset in radius to diameter range can beneficial toinhibit or eliminate the HOOK interface distortion structure to some extent.