Effects of In-Situ BaB6/Al Composite Inoculant on the Mechanical and Corrosion Behavior of Al-7Si-0.3Mg Alloy

In this work, as an inoculant, in-situ BaB6/Al composites was fabricated and used to refine the alpha-Al dendrites and modify the eutectic Si of A356.2(A1-7Si-0.3Mg) alloy. BaB6/Al ingot and ribbon composites mainly contain two phases, alpha-Al and BaB6. In BaB6/Al ribbons, nano-size BaB6 ceramic particles exist and disperse uniformly which help to better exert the inoculant effect in A356.2 alloy. YS, UTS, EL and HV of B2 alloy are 36.3%, 18.3%, 46.4% and 20.8% higher than the base alloy (B0), respectively. The ductile fracture characteristics are more obvious. Moreover, B2 alloy shows the best corrosion resistance. Al and BaB6 form a clear, stable and well matched interface, so BaB6 particles can act as the heterogeneous nucleation of alpha-Al and refine the A356.2 alloy. Furthermore, the combined of free micro-alloying elements Ba and B in BaB6/Al composites promote the twins formation, which change the eutectic Si to fine fibrous and granular shape.