Interface characteristics and mechanical properties of the induction brazed joint of magnesium alloy AZ31B with an Al-based filler metal

In this paper, wrought magnesium alloy AZ31B sheets were brazed by means of high-frequency induction heating device using a novel Al-based filler metal in argon gas shield condition. The interfacial microstructure, phase constitution and fracture morphology of the brazed joint were studied. The experimental results show that α-Mg solid solution and β-Mg17Al12 phase were formed in brazing region. Moreover, the homogeneous Mg32(Al, Zn)49 phase in the original Al-based filler metal disappeared entirely after the brazing process due to the fierce alloying between the molten filler metal and the base metal during brazing. Test results show that the shear strength of the brazed joint is 45 MPa. The fracture morphology of the brazed joint exhibits intergranular fracture mode and the crack originates from the hard β-Mg17Al12 phase.

► A novel Al-based filler metal is designed to join magnesium alloy AZ31B.
► AZ31B sheets can be jointed by means of brazing with Al-based filler metal.
► The α-Mg solid solution and β-Mg17Al12 phase are formed in the brazing region.
► Mg32(Al, Zn)49 phase in the filler metal is consumed after the brazing process.
► The fractography of the brazed joint exhibits intergranular fracture mode.