Interface and precipitate investigation of a TiB2 particle reinforced NiAl in-situ composite

The TiB2 particles reinforced NiAl alloy composite was fabricated by hot-pressing aided exothermic synthesis (HPES). The interface between TiB2 reinforcement and NiAl matrix and the precipitate in composite were studied by transmission electron microscopy (TEM). The experimental results show that there is no reaction product formation at the TiB2/NiAl interface and the relationships between TiB2 and NiAl have no specific orientations. In addition, a fcc phase with lattice constant a=1.05 nm precipitated in TiB2/NiAl composite. TEM energy dispersive X-ray spectroscopy analysis of this fcc phase indicated that it contains element Ni, Al and B with near atomic ratio 20:3:6, thus, this fcc phase is a boride, Ni20Al3B6.