Microstructure characteristics and properties of steel stud to aluminum alloy made by covering filler metal brazing

Q235 steel stud and 6061 aluminum alloy with AlSi as filler metal were joined by using high-frequency induction brazing.Microstructure, composition and phase composition of the welded joint were characterized by optical microscopy, SEM, EDAX EDS diffraction analysis.The results showed that AlSi filler completely reacted to 6061 aluminum base metal, needle-like eutectic was formed with the diffusion of Si to aluminum base metal;continuous Fe-Al intermetallic compounds which should be composed of Fe₂Al₅ and FeAl₃ generated near the steel side in the brazing seam, and some cellular crystal generated along the direction perpendicular to the Al base metal.Mechanical properties tests showed that the shear strength of welding joint was up to 65 MPa, fracture occurred in the Fe-Al intermetallic compounds where the microhardness was high.Fracture properties belonged to ductile fracture.