The effect of stirring rate on semisolid stirring brazing of SiCp/A356 composites in air

This paper explores the possibilities of joining SiCp/A356 composites using semisolid Zn27Al filler metal with aid of mechanical stirring. Moreover, the effect of stirring rate on the macro-appearance, microstructure, bonded ratio, braze metal ratio of joints and the tensile strength of joints were investigated. Experimental results show that the bonded ratio of interface, braze metal ratio and the tensile strength of the joints is rise with increasing of stirring rate. It is indicated that increasing of stirring rate will promote the disruption of oxide film on surface of composites so as to enhance metallurgical bonds at joint interface. In addition, increasing of stirring rate will also promote formation to fine brittle η-Zn phase and its uniform distribution in bond.

► Mechanical stirring and semi-solid filler metal has been used during brazing in air.
► Mechanical stirring has been introduced to disrupt the oxide film of composites.
► High stirring rate will promote the disruption of oxide film of composites.
► With increasing of stirring rate, the bonded ratio of interface is rises gradually.
► With increasing of stirring rate, the tensile strength of joints is rises gradually.