Assessing the influence of fieldshaper material on magnetic pulse welded interface of Al/Cu joints

Fieldshaper (FS) is a widely used component in magnetic pulse forming and welding to improve the efficiency of the process. It enables to increase the magnetic pressure experienced by the workpieces during forming and welding. Recent developments in this subject focuses to increase the life time of the fieldshaper and to improve the efficiency by introducing shape optimized designs. In this study, we compare the efficiency of four fieldshapers made of Cuprofor, Siclanic, CuBe2 and Steel. The main focus is given to the effect of material properties while the same geometry was considered for those four fieldshapers. The same welding conditions (discharge voltage of 6kV and air gap of 1.64 mm) are used to weld Al/Cu. Fieldshaper made of steel could not successfully produce a welding under the aforementioned welding conditions. Welding performed using CuBe2 and Siclanic fieldshapers produces similar features of the welded interfaces, those have wavy zone, swirls, cracks, discontinuous intermediate (IM) layers, and a few IM pockets. Cuprofor fieldshaper also generates these features but the welded interface reveals significantly large kinetic instabilities due to the presence of large vortex, large holes within swirls and porous intermediate phases (IMP). These results clearly show the importance of choosing the appropriate fieldshaper material to produce successful welds and the resulting instabilities features at the interfaces. (C) 2019 The Authors. Published by Elsevier B.V.