Interfacial microstructure of stainless steel/aluminum alloy tube lap joints fabricated via magnetic pulse welding

The mechanical properties and interfacial microstructure of slices of friction stir welded aluminum alloy/stainless steel dissimilar lap joints were characterized. In an FSWed A3003 aluminum alloy/SUS304 steel lap joint, the strength on the advancing side was larger than that at the retreating side. TEM observation indicated that a sound joint that fractured at the base metal can be obtained from the stage of the formation of the amorphous layer owing to the mechanical alloying effects before the formation of intermetallic compounds. This lap joining technique was also successfully applied to A6061/T6 aluminum alloy-grooved SUS304 plates. Equiaxed aluminum grains were observed at the interface of the specimen after it was fractured, indicating that the interface deformed only slightly during the microtensile test. It was found that tensile strength of the joint was increased by aging at 433K, considering that precipitation occurred at this temperature. In addition, it was confirmed that the joint heated at 723K for 1.8ks still fractured at the aluminum matrix, assuming that intermetallic layers at the interface would slightly grow in this heating condition.

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Experimental and Numerical Investigations into Magnetic Pulse Welding of Aluminum Alloy 6016 to Hardened Steel 22MnB5

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp5030066 ◽

2021 ◽

Vol 5 (3) ◽

pp. 66

Author(s):

Rico Drehmann ◽

Christian Scheffler ◽

Sven Winter ◽

Verena Psyk ◽

Verena Kräusel ◽

...

Keyword(s):

Aluminum Alloy ◽

Base Material ◽

Soft Materials ◽

Lateral Position ◽

Process Window ◽

Magnetic Pulse ◽

Magnetic Pulse Welding ◽

Lap Shear ◽

Pulse Welding ◽

The Impact

By means of magnetic pulse welding (MPW), high-quality joints can be produced without some of the disadvantages of conventional welding, such as thermal softening, distortion, and other undesired temperature-induced effects. However, the range of materials that have successfully been joined by MPW is mainly limited to comparatively soft materials such as copper or aluminum. This paper presents an extensive experimental study leading to a process window for the successful MPW of aluminum alloy 6016 (AA6016) to hardened 22MnB5 steel sheets. This window is defined by the impact velocity and impact angle of the AA6016 flyer. These parameters, which are significantly dependent on the initial gap between flyer and target, the charging energy of the pulse power generator, and the lateral position of the flyer in relation to the inductor, were determined by a macroscopic coupled multiphysics simulation in LS-DYNA. The welded samples were mechanically characterized by lap shear tests. Furthermore, the bonding zone was analyzed by optical and scanning electron microscopy including energy-dispersive X-ray spectroscopy as well as nanoindentation. It was found that the samples exhibited a wavy interface and a transition zone consisting of Al-rich intermetallic phases. Samples with comparatively thin and therefore crack-free transition zones showed a 45% higher shear tensile strength resulting in failure in the aluminum base material.

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