Synthesis of TiAl–(TiB2+Ti2AlN) Composites by HIP Reactive Sintering

Intermetallic compound TiAl-base composites have been prepared by the hot isostatic pressing (HIP) reactive sintering technique. These composites have been synthesized from a powder mixture of titanium, aluminum and boron nitride, and contain Ti2AlN and TiB2 strengthening particles. Nearly spherical particles of Ti3Al and Ti2AlN of about 20 μm in diameter have been embedded in the TiAl phase. The composite has been found with a dual phase matrix structure. The Ti2AlN phase is composed of about 300–500 nm grains and includes dispersion of nano scaled TiB2 particles (about 50–100 nm). Both compression tests and hardness measurements have revealed that this composite material attains higher strength as compared with non-reinforced TiAl. The insufficient bending ductility, however, hinders its bending fracture strength at ambient temperature.