At the present stage, there are many points which
are yet to be clarified for resistance spot brazing
with use of sheet type filler metal. It is clear that
bond strength is not large enough for joining between
Al/steel. However, the sheet type filler metal interacted with steel/aluminum sheet and resulted in forming uniform layer at interface. Figure 8 shows microstructure of the interfacial layer between the filler metal layer and steel sheet. It is clearly seen that uniform mixed layer (mark B) is formed on the interface
between filer metal and steel sheet.