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Background. Electromagnetic Pulse Technology (TEM) is a non-contact pulse process with great potential for connecting dissimilar materials. This method uses pulsed electromagnetic fields to form and connect metals with high conductivity, such as aluminum or copper. This process makes it possible to perform connections with geometric closure and tension due to compression or expansion of profile structures of alloys with a closed cross section, as well as metallurgical welds. Despite the technological advantages and potential, only a modest introduction into industrial applications has been found. This scientific article aims to reveal the industrial interest and applicability of electromagnetic pulse technology in various subsectors of the microelectronic industry, promoting lightweight and highprecision engineering components. Materials and methods. Based on numerical and experimental studies, copper-copper and copper-aluminum electrical connections are produced by electromagnetic pulse crimping. The main parameters are determined and their influence on the connection process and the achievable strength of the connection is analyzed. Attention is paid to the development of electromagnetic drives. The fundamentals of the theory of magnetic and pulsed welding are applied. Results. Conclusions and instructions on the design of the manufacture of compounds using electromagnetic pulse technology are given. A simplified approach to modeling is presented for numerical studies. This unrelated approach makes it possible to successfully develop the process and design of the connection for electromagnetic pulse crimping. Various welding parameters are indicated, which determine the different morphology of the surface, the section with different mechanical strength. The influence of the mandrel surface on the quality of the joint is evaluated. Conclusions. The weldability criteria for copper and aluminum compounds have been experimentally determined. The influence of several parameters of the experimental welding process, namely the discharge energy, gaps and holes, is evaluated using destructive tests.

Two types of intermediate layer (IML) were formed at the magnetic pulse welded Al/Fe joint interface. To clarify the formation mechanism of IML, the cooling process at the joint interface and formation process of IML were analyzed by the simulation and experiment. The simulation results showed that the crest zone of wavy interface underwent an extremely high temperature rise during the collision process, the high temperature leads to a local melting behavior at the joint interface. After the collision, a large temperature difference of 1000-1500K between joint interface and base metals caused a rapid cooling occurred at the interface with a cooling rate reached around 107~109K/s. Meanwhile, local melting zone (LMZ) changed into IML during a rapid solidification that proceeded from the outside and finished at the center area of LMZ. The morphology and composition percent of IML calculated by the numerical analysis was quantitatively in good agreement with experimental analysis results. A reasonable explanation has been made on the formation mechanism of IML at magnetic pulse welded Al/Fe joint interface. [ABSTRACT FROM AUTHOR]

A 1050-O aluminum plate and a low carbon steel (SPCC) plate were seam welded by magnetic pulse welding (MPW). Experimental and numerical analysis methods were combined to investigate the wavy interface formation and local melting phenomena at the Al/Fe joint interface. The metallographic observation results showed that Al/Fe joint interface presents a trigger-like wave shape with two types of intermediate layers intermittently formed at the interface. Collision angle between two plates and impact velocity of Al sheet driven by electromagnetic force was numerically solved by coupled mechanical and electromagnetic fields analysis. The metal jet emission behavior, wavy interface formation process and the temperature change during MPW collision process was analyzed by SPH method. The numerical results showed that the temperature near the interface exceeds the melting point of both Al and Fe at extremely high pressure, which leads to the formation of a local melting zone (LMZ) where Al and Fe were mixed in melted state. The numerically reproduced wavy interface morphology showed a good consistency with the experimentally observed results. [ABSTRACT FROM AUTHOR]

The microstructure of aluminum‐steel compounds fabricated by magnetic pulse welding are investigated. Electron backscatter diffraction, energy dispersive x‐ray spectroscopy and scanning electron microscopy revealed the existence of several different phases along the weld seam. While one layer could be identified as aluminum solid solution, a very thin layer close to the steel side of the compound eluded detailed characterization by scanning electron microscopy techniques. Transmission electron microscopy and selected area electron diffraction investigations of this layer revealed a mix of nanocrystalline and amorphous parts. When ambient pressure was reduced to 1 mbar during welding, no interlayers were observed in the samples. This suggests that the interlayers are precipitates of the jet that is formed during conventional impact welding. [ABSTRACT FROM AUTHOR]

Collision welding is a high-speed joining technology based on the plastic deformation of at least one of the joining partners. During the process, several phenomena like the formation of a so-called jet and a cloud of particles occur and enable bond formation. However, the interaction of these phenomena and how they are influenced by the amount of kinetic energy is still unclear. In this paper, the results of three series of experiments with two different setups to determine the influence of the process parameters on the fundamental phenomena and relevant mechanisms of bond formation are presented. The welding processes are monitored by different methods, like high-speed imaging, photonic Doppler velocimetry and light emission measurements. The weld interfaces are analyzed by ultrasonic investigations, metallographic analyses by optical and scanning electron microscopy, and characterized by tensile shear tests. The results provide detailed information on the influence of the different process parameters on the classical welding window and allow a prediction of the different bond mechanisms. They show that during a single magnetic pulse welding process aluminum both fusion-like and solid-state welding can occur. Furthermore, the findings allow predicting the formation of the weld interface with respect to location and shape as well as its mechanical strength.

Collision welding is a high-speed joining technology based on the plastic deformation of at least one of the joining partners. During the process, several phenomena like the formation of a so-called jet and a cloud of particles occur and enable bond formation. However, the interaction of these phenomena and how they are influenced by the amount of kinetic energy is still unclear. In this paper, the results of three series of experiments with two different setups to determine the influence of the process parameters on the fundamental phenomena and relevant mechanisms of bond formation are presented. The welding processes are monitored by different methods, like high-speed imaging, photonic Doppler velocimetry and light emission measurements. The weld interfaces are analyzed by ultrasonic investigations, metallographic analyses by optical and scanning electron microscopy, and characterized by tensile shear tests. The results provide detailed information on the influence of the different process parameters on the classical welding window and allow a prediction of the different bond mechanisms. They show that during a single magnetic pulse welding process aluminum both fusion-like and solid-state welding can occur. Furthermore, the findings allow predicting the formation of the weld interface with respect to location and shape as well as its mechanical strength. [ABSTRACT FROM AUTHOR]