Interface behavior of steel/Al tube assisted semi-solid brazing by magnetic pulse

A semi-solid brazing process assisted by magnetic pulse for steel/aluminum tube was proposed by combining electromagnetic forming technology and semi-solid brazing technology. The brazing of steel and aluminum dissimilar pipes without flux soldering was realized by means of the radial compression and axial shear action of solid particles in the semi-solid solder to remove the oxide film on the surface of the base metal. The diffusion behavior of interface elements and the growth mechanism of intermetallic compounds in brazing joints were studied by magnetic pulse semi-solid brazing experiments of steel/aluminum tubes under different process parameters. The results show that the weld microstructure is mainly composed of α-Al and zinc-rich phase. The Al₂O₃ oxide film at the aluminum side interface is broken and removed well, and a thin layer of FeAl₃ intermetallic compound is formed at the steel side interface. Good metallurgical bonding is achieved at all parts.