Capacitive Discharge Welding (CDW) is a similar process to RSW except large amount of energy is released in relatively a short amount of time. A research group at The Ohio State University working under supervision of Dr. Menachem Kimchi and Jerry Gould from EWI has investigated the feasibility of Al/Steel joining via this process. Figure 1 shows the current waveforms at 1.3ms & 2.5 and their mechanical strength results.
A shorter amount of time can significantly suppress the growth of the intermetallics. The group reported that higher amount of current in short duration of time could result in stronger welds. Figure 15 shows the effect of time on the growth of intermetallic (IMC) and solidification pattern. At 1.3 ms IMC layer thickness is less than 3 microns whereas at 2.5 ms the IMC layer thickness was reported greater than 3 microns. If IMC layer is less than 3 microns it results in nugget pull out failure mode whereas IMC layer of 3 microns or greater mostly result on interfacial failure.P-10