Deformation Of Magnetic Pulse Welding Of 3A21-SS304 Tubes And Effect Of The Local Features On The Joint

With the improvement of the use environment and lightweight requirements,it is urgent to realize the joining of different kinds of materials to meet the requirements of strength,weight loss and corrosion resistance.The generation of aluminum/steel metal composite materials provides a good solution for the connection of aluminum and steel materials.The composite structure of aluminum alloy and stainless steel can give full play to the inherent properties of two materials,reduce structure's weight and extend the function of parts and increase the fatigue life of parts and reduce the use of rare precious metals.It has high application potential in automobile,aerospace and shipbuilding.Based on the numerical simulation and the experiment,the influence of the geometric characteristics that are prefabricated at the surface of the steel tubes on the deformation of magnetic pulse welding(MPW)and the joints are analyzed in this study.Through the finite element analysis software ANSYS,the accelerated motion of aluminum alloy and stainless steel in the deformation process of MPW is analyzed.The influence of different features and its geometric parameters on the joints is analyzed to get the law of influence which could guidance the process of MPW.The research also analyzes the deformation of interface in the process of impact by smoothed particle hydrodynamics(SPH)method,exploring the deformation mechanism of interface in MPW.The 3A21 aluminum alloy tube and 304 stainless steel tube were joining by MPW.And the joints under different features were stripped,by which the quality of the joints were judged preliminarily.Then the mechanical properties of the joints were tested by the shear test.The results show that the joints' strength under the convex features is higher than the joints' strength under the inclined features and the concave features.The maximum of the shear strength of the joints is 676N/mm under the convex feature,at which the initial angle range of 0-5 degrees was prefabricated.The optical microscope and SEM were used to observe and analyze the microstructure of the interface of the joints under different features,and it is found that there are four kinds of typical morphology of 3A21/SS304 interface:wave interface with transition layer,wave interface without transition layer,straight interface with transition layer and straight interface without transition layer.Porous and pores are found in the transition layer.The interface with transition layer was analyzed and tested by EDS,and the influence of different features on the distribution of interface components was analyzed.The hardness of the joints under different features was tested by the nano indentation instrument,and the influence of the types of features and the prefabricated angle range on the hardness of the interface was studied,and the reasons for the increase of the hardness of the interface were analyzed.