Duralumin-stainless steel joint: structure and mechanism of forming by means of electron beam welding and Ag-2Mg filler metal shim

High-alloyed stainless steel of 18-8 type and duralumin are not directly weldable due to significant differences in their properties. The results of structural investigations of the joints between the two materials, obtained by a previously developed method of electron beam welding with an Ag-2 wt% Mg alloy filler metal shim, are presented in this paper. The microstructure of the weld is diphasic, being composed of supersaturated Ag in Al solid solution and also an Ag₂Al phase. At the base materials and weld boundaries interstitial layers are crystallized in the form of solid solutions while brittle intermetallic compounds do not appear. On the basis of presented results a mechanism for the joint formation is proposed.