The B2 Aluminides As Alternative Materials

Abstract

ABSTRACTAs part of NASA's Conservation of Strategic Aerospace Materials (COSAM) Program, a research effort is underway to explore the potential of the B2 aluminides as structural material alternatives for the strategic element containing superalloys currently used in gas turbine engines. Emphasis is being place on the equiatomic Fe and Ni aluminides. Although Co is a strategic material, the equiatomic Co aluminide is also being studied to gain a more complete understanding of these fourth period intermetallics. The research effort is a cooperative program involving in-house research at NASA Lewis plus several university grant programs. Research focuses on initial processing techniques such as ingot melting, powder metallurgy, and rapid solidification with and without additional thermomechanical processing; high temperature deformation - primarily compressive creep; compositional effects within the binary B2 aluminides; third-element alloying addition effects on high temperature strength and oxidation resistance; and near room temperature ductility as influenced by processing, alloying, and grain size. This paper will review the various programs now underway and present some of the highlights of research results.