Abstract
In the present paper, joinability and interfacial metallurgical phenomena in explosive welding are experimentally examined for different combinations of aluminium alloys containing or no magnesium and mild or stainless steels with the purpose of clarifying the reason why aluminium alloys containing magnesium can be hardly joined with steel by explosive welding. The experiments show the following facts.
The aluminium alloys are soundly bonded with one another, and remarkable segregation of magnesium is observed inside microvoids within fusion layer produced at a certain weld boundary between Al-Mg alloy and aluminium, from which it is deduced that evaporation and condensation of magneisum occur in the molten alloy overheated during the welding process.
The explosive process for flyer plate of Al-Mg alloy and parent plate of mild or stainless steel results in poor or no weld accompanied by formation of fusion layer at the boundaries. The fusion layers between Al-Mg alloy and mild steel have chemical compositions mainly based on the Al-Mg alloy, comparatively high hardness, and a tendency to cause microcracks in them; and at the non-welded interface, too, segregation of magnesium is observed together with the fusion layer.
