Casting of single phase ordered Intermetallic compound of Ni3Al, a substitution for Nickel-base superalloys for high temperature structural application

Ni3Al phase is the most important strengthening constituent (γ phase) of commercial nickel - base superalloys and is responsible for their good high temperature strength and creep resistance. The Ni3Al alloys are resistant to air oxidation because of their ability to form adherent oxide films that protect the base metal from excessive attack. Ni3Al is an ordered intermetallic phase with L12 structure which have very interesting mechanical properties ar high temperatures. One outstanding characteristic of most intermetallics is that their strength does not decline rapidly with increasing temperature. In many cases, the yield stress of these alloys increases rather than decreases with test temperature, in contrast to conventional alloys such as austenitic stainless steels. This behavior referred as anomalous behavior of most aluminides makes intermetallic alloys particularly suitable for use at elevated temperatures. In addition density of single phase Ni3Al is free from two strategic elements of Co and Cr. Hence with respect to factors like lifetime and efficiency and price the need for design of new material is well established. In this research work casting of single phase Ni3Al ordered intermetallic compound, as the main aim, has been done and after casting characterization of ingots to prove it's chemical composition as well as its ordered structure have been carried out