Transmission electron microscopy study of precipitates in a NiAl–TiB2 composite

A TiB2 particle-reinforced NiAl alloy composite was fabricated by hot-pressing aided exothermic synthesis. The microstructures of the composite were investigated by transmission electron microscopy (TEM). The experimental results show that a fcc phase with lattice constant a=1.05 nm precipitated in the TiB2/NiAl composite. TEM energy dispersive X-ray (EDX) spectroscopy (Philips, CM200 FEG, spot size: 5 nm) analysis on this fcc phase indicated that it contains the elements Ni, Al and B with near atomic ratio 20:3:6, thus, this fcc phase is a boride, Ni20Al3B6.