Herstellung und Erprobung von intermetallischen Phasenwerkstoffen fuer hochbeanspruchte Triebwerkskomponenten. Teilprojekt: Nickel- und Kobaltbasisaluminide Abschlussbericht

Abstract

The central objective of the project documented here was the development of NiAl and CoAl base alloys for highly stressed engine components in hypersonic aircraft. To improve the creep strength of these materials and their toughness at ambient temperature, alloying measures were used to introduce finely distributed ductilizing phases into the temperature resistant structured intermetallic matrix phase. For this purpose alloying systems were selected, in which NiAl or CoAl coexist with a more ductile phase as compared to the intermetallic compound. The quasi-binary systems NiAlCr, NiMo, NiW, NiRe feature two-phase alloys whose structure consists of the intermetallic matrix phase NiAl and a finely distributed element phase having a highly symmetrical lattice structure. Differently processed eutectic and hypoeutectic NiAl and CoAl base alloys were investigated for their microstructure as well as for their physical and mechanical properties. The inclusion of Ni_3Al or Co into the NiAl or CoAl matrix phase causes a significant increase of ambient temperature toughness. At temperatures above 1,000 C, alloys of this system exhibit only insufficient high-temperature resistance. The addition of Cr and Mo to the intermetallic phase NiAl significantly increases both the ambient temperature toughness and high-temperature resistance of the NiAl base alloy. (orig./RHM)SIGLEAvailable from TIB Hannover: F95B1625 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman