1.Magnetic Pulse Welding

Magnetic pulse welding (MPW) is one of the impact solid-state welding methods. When metal plates collide obliquely at high
speed, such as several hundreds of meters per second, the interface layer of the plate is emitted as metal jet. Consequently,
atoms on the cleaned surface establish strong metallurgical bond. This process is achieved at a few microseconds. This method
is adaptive for wide variety of similar- and dissimilar- combinations of metals.

   We have researched magnetic pulse welding for several years. Figure 1 shows the schematic illustration of magnetic pulse
welding. In magnetic pulse welding, flyer plate deforms partially at high speed by Fleming’s left-hand law, and collides into parent
plate. The weld interface shows wavy morphology (Figure 2), and the region along the weld interface is composed of amorphous
layer and ultrafine grains. Multilayer lap joints of Al plates (Figure 3) and metal-metallic glass lap joints were also fabricated by
this method.

Fig.1 Schematic illustration of 　　magnetic pulse welding
	(a)
Fig.3 Multilayered lap joint of Al plates	(b)
	Fig.2 Weld interface(Al:Al/Ni, b:Al/Al)

　 Figure 4 showsmagnetic pulse welding process, which was revealed taken by using high-speed video camera. This is the first
successful in-situ observation of the world. The collision behavior of metal plates and the metal jet emission from the collision
point are detected clearly.

　　　　　　　　　　　　　　　
　　　　　　　　　　　　　　　　Fig.4 In-situ observation of magnetic pulse welding process by high-speed video camera

    We currently research on the characteristic weld interface morphology and the metal jet emission behavior in several similar-
and dissimilar- impact welded lap joining from both by numerical analysis and experimental methods. The chemical components of
metal jet are also investigated.

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
　　　　　　　　　　　　　　　　　　　　　Fig.5 The metal jet emision and the wavy interface produced in simulation


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