Bonding zone formation in magnetic pulse welds

Abstract

The microstructural features of the bonding zone in magnetic pulse welds of similar and dissimilar metal pairs have been investigated. The nature of the reactions and phase formation that occur in the magnetic pulse joints displaying a discontinuous pocket type or a continuous transition layer along the bond interface is explained in terms of local melting followed by rapid solidification. The most significant feature of the transition zone created during the magnetic pulse welding process is the hardness increase of the interface layer. For similar base metals the main cause of the hardness increase is the fine grained microstructure created during the rapid local solidification. In the dissimilar base metal welds the increase in hardness is a result of the formation of stable or metastable intermetallic phases and of the fine grained microstructure of the bonding zone.

Preliminary Investigations of Joining Technologies for Attaching Refractory Metals to Ni-Based Superalloys

“…In addition, small volumes of material which etch differently than either the Hastelloy X or T-111 base metals can be observed. Similar transition zones have been observed elsewhere for dissimilar magnetic pulse-welded joints (Seregeeva, Chudakov, and Gordon, 1989;Stern and Aizenshtein, 2002), and have been related to local resolidified volumes of molten material.…”

“…It is also clear that the process resulted in substantial indentation of the target bar stock. Details of the bondline between the tube and bar stock are shown more clearly in Figure 12 where the wavy character of the bond line, typical of magnetic pulse welds is apparent (Shriban et al, 2000;Seregeeva, Chudakov, and Gordon, 1989;Stern and Aizenshtein, 2002). The micrograph also shows local deformation of the Hastelloy X bar stock and T-111 tube.…”

“…Repulsion of these two currents leads to the Lorenz forces that create the subsequent weld. Microstructures of the resulting bonds have also been widely studied (Efimenko et al, 1985;Seregeeva, Chudakov, and Gordon 1989;Markashova et al, 1991;Stern and Aizenshtein, 2002). Best bonding is generally equated with wavy interfaces, similar to those seen in explosion welding.…”

Electromagnetic impact welding of aluminum to stainless steel sheets

“…Due to the ease in controlling the magnetic field enveloped inside the tube the electromagnetic technique has been widely used for tube welding (Powers, 1967;Hwang, 1992). This has been further investigated in detail for characterizing the EM welding technique for welding of similar and dissimilar metal tubes (Marya and Marya, 2004;Stern and Aizenshtein, 2002;Marya et al, 2005;Shribman et al, 2002;Kimchi et al, 2004;Zhang and Daehn, 2004). In case of flat components controlling the magnetic field is difficult.…”

Electromagnetic impact welding of copper-to-copper sheets

“…Ease in enveloping the magnetic field inside the tube restricted the application of electromagnetic welding technique to tubular workpieces [4,14]. Many researchers have carried out the detailed analysis of EM welding of tubes [5,10,11,16,17,19]. Concentration of magnetic field is difficult in case flat sheets and hence this field has not been widely researched.…”