Peel and lap-shear tensile tests were used to provide a quick estimate of the joining quality. The schematic drawing of the lap-shear tensile test is shown in Fig. 1.
The results of the peel tests indicated that a weld button was easily achieved when
the peeling was conducted between the steel sheet and the aluminum sheet.
With the various combination of weld current and time, weld nugget development studies were conducted experimentally to achieve indepth, fundamental understanding of the nugget formation sequence of the weld with weld step such as post weld heat treatment. The detailed weld parameters are shown in Table 1. This was accomplished
by consecutively metallurgically cross sectioning the
weld and etched with observation of interfacial microstructure. The specimens were polished and etched in 3% natal and keller etchant for microstructure observation.
The electron microscopy technique was used for depth analysis to detect IMC layer around
the interface layer.