Multiphase niobium aluminides fabricated via reaction synthesis

The formation of Multiphase niobium aluminides by a series of reaction synthesis, was analyzed. The aluminides exhibit high elastic stiffness, high melting points, strength and creep resistance at elevated temperatures. The melting and casting of these aluminides presents several difficulties due to requirement of high temperatures, high evaporation rate of aluminum and the difference in melting points and densities of niobium and aluminum. The reaction synthesis provides some solution to these problems such as, short heating and cooling times which results in fine scale microstructures and reduced contamination from mould materials and atmosphere, shape forming thereby reducing the machining requirements. The first step of the reaction mechanism was the complete melting of aluminum which remains liquid for a significant period of time. It was observed that the appearance of liquid aluminum support the solid-state formation of intermetallic phases prior to the melting of aluminum.