Microstructural characterisation of interfaces in magnetic pulse welded aluminum/aluminum joints

18th Chemnitz Seminar on Materials Engineering – 18. Werkstofftechnisches Kolloquium

Sharafiev, S.^1 ; Pabst, C.^2 ; Wagner, M.F.-X.^1 ; Groche, P.^2

Department of Materials Science, Institute of Materials Science and Engineering, Technische Universität Chemnitz, Chemnitz

D-09125, Germany^1

Institute for Production Engineering and Forming, Technische Universität Darmstadt, Dramstadt

D-64287, Germany^2

关键词: Aluminium structures;    Columnar grain structure;    Electron backscatter diffraction technique;    High velocity collisions;    Micro-structural characterization;    Microstructural characterisation;    Multi-material structure;    Optical and electron microscopies;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/118/1/012016/pdf
DOI  :  10.1088/1757-899X/118/1/012016

来源: IOP

【 摘 要 】

Electromagnetic pulse welding provides novel and useful solutions in the field of multi-material structures. The joining occurs through the high-energy mechanical impact of metal sheets, which leads to a strong, cohesive, metallic bonding between the sheets. The high- velocity collision results in changes of the microstructure in the regions adjacent to the interface. The aim of this work is the microstructural characterization of the interface and the welding zone of Al/Al joints. One typical interface is analysed by optical and electron microscopy and using the electron backscatter diffraction technique. Our results show that the interface exhibits a well-known type of wavy weld geometry. Moreover, the formation of an intermediate layer that is different from the bulk aluminium structure is observed. The microstructure of this intermediate layer consists of ultrafine grains and in some regions exhibits a columnar grain structure. It is likely that this special microstructure (which plays an important role in determining the cohesive, continuous bonding between the metal sheets) is formed through a rapid melting and crystallisation process in the interface region.