Laser welding-brazing of alumina to 304 stainless steel with an Ag-based filler material

Abstract

In this paper, laser welding-brazing of 304 stainless steel (SS) and Al2 O3 ceramic dissimilar metal material was carried out. The results showed that the SS and Al2 O3 were joined by melting filler metal when the laser was focused on the SS side of the joint. One process was one pass welding involving creation of a joint with one fusion weld and one brazed weld separated by remaining unmelted SS. When laser beam was focused on the SS plate 1.5 mm, SS would not be completely melted in joint. Through heat conduction, the filler metal (68.8 wt.% Ag, 26.7 wt.% Cu, 4.5 wt.% Ti) melting occurred at the SS-Al2 O3 ceramic interface. A brazed weld was formed at the SS-Al2 O3 ceramic interface with the main microstructure of Cu[s.s.] + Ag[s.s.], Ti2 Cu + TiFe and Ag + AlCu2 Ti. The joint fractured in reaction layer at the ceramic side with the maximum tensile strength of 74 MPa.