Hot extrusion reaction synthesis of nickel, titanium and iron aluminides

The research presented here describes the results of production trials of various nickel, iron and titanium aluminides, using the method of hot extrusion reaction synthesis (HERS). Billets of the elemental powder mixtures have undergone HERS in a specially designed experimental scale extrusion rig. The ease of processing was highly dependant on the container (tooling) temperature, the heating time of the billet, the ram speed during extrusion, the composition and the aluminide system in question. HERS has been successful with aluminides based on the stoichiometric ratios of FeAl and Ni3Al at relatively low container temperatures (less than 600 °C). The extruded microstructures consisted of a mixture of intermetallic phases. The short processing cycle led to fine grain sizes and high values of mechanical properties, such as yield strength.