Bond formation between aluminum-based metal matrix composites and aluminum alloys in compound castings

The use of inserts allows for the selective reinforcement of castings to improve mechanical properties, including surface hardness and wear rate. Metal surfaces that undergo wear on account of friction can be strengthened using metal matrix composite (MMC) inserts. An essential factor in the manufacture and application of compound casting involving MMC inserts has been the bond strength between the insert and alloy. This work studied fluxes (CsAlF4 and LiAlF4), preheating, and nickel (Ni) plating to improve the bond strength between A206 and A201-Al₂SiO₅ fiber MMC. It was observed that Flux 1 (G-2004), Flux 2 (CS-2020), and Ni plating, when used with preheating the insert up to 200 °C, led to the formation of a diffusion bond. The effect of fluxes and plating has been discussed, along with the impact of the insert oxide layer on the formation of diffusion bonds. The microstructure formed at the interface between casting and insert was analyzed.