Synthesis and characterization of in situ formed titanium diboride particulate reinforced AA7075 aluminum alloy cast composites

In situ fabrication of aluminum matrix composites (AMCs) has gathered widespread attention of researchers due to inherent advantages over ex situ methods. Aluminum alloy AA7075 reinforced with various amounts (0, 3, 6 and 9 wt.%) of TiB2 particles were prepared by the in situ reaction of inorganic salts such as K2TiF6 and KBF4 to molten aluminum. X-ray diffraction patterns of the prepared AMCs clearly revealed the formation of TiB2 particles without the presence of any other intermetallic compounds. The microstructures of the AMCs were studied using optical and scanning electron microscopy. The in situ formed TiB2 particles were characterized with uniform distribution, clear interface, good bonding and various shapes such as cubic, spherical and hexagonal. The formation of TiB2 particles enhanced the microhardness and ultimate tensile strength (UTS) of the AMCs.

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► Fabrication of AA7075/TiB2 AMC by in situ reaction K2TiF6 and KBF4 salts.
► Most of the TiB2 particles were located in inter granular regions.
► Uniform distribution of TiB2 particles having clear interface and good bonding.
► TiB2 particles displayed various shapes such as cubic, spherical and hexagonal.
► TiB2 particles enhanced the mechanical properties of the AMC.