Fabrication of in situ TiB2 particulates reinforced zinc alloy matrix composite

• TiB2 particulates reinforced ZA27 matrix composite was fabricated by a novel two-step in situ reaction method
• The TiB2 particles are pushed into the interdendritic regions by the primary α-Al phases in composite.
• The morphology of primary α-Al and η-Zn phase varies considerably in composite.
• The ZA27/TiB2 composite showing better mechanical properties compared to the matrix alloy.

The zinc–aluminum ZA27 alloy matrix composite reinforced with TiB2 particulates has been in situ produced via direct melt reaction technology from the Al–K2TiF6–KBF4 system. The X-ray diffraction patterns revealed the presence of TiB2 peaks while no discernible appearance of brittle Al3Ti and AlB2 peaks, indicating the completion of reaction. The SEM micrographs revealed that the composite exhibited finer primary α-Al dendritic structure with TiB2 particles addition. The in situ formed TiB2 particles are mainly distributed in the interdendritic regions between the primary α-Al dendrites in ZA27 alloy matrix composite. The introduction of TiB2 particles significantly enhanced the microhardness and ultimate tensile strength (UTS) of ZA27 alloy.