Microstructures of L21/L12
multi-phase intermetallics in Co-Ni-Al-Ti system
multi-phase intermetallics in Co-Ni-Al-Ti system
(Department of Materials Science and Engineering,
Beijing University of Aeronautics and Astronautics, Beijing 100083, P.R.China)
Beijing University of Aeronautics and Astronautics, Beijing 100083, P.R.China)
Abstract: On the basis of the two ternary systems of Co-Al-Ti and Ni-Al-Ti, a series of high-temperature structural intermetallic alloys comprised of L21-type (Co, Ni)2AlTi and L12-type (Co, Ni)3(Al, Ti) ordered phases in the Co-Ni-Al-Ti quaternary system were designed and melted to take the advantages of both the high elevated temperature strength of the L21 phase and the intrinsic room temperature ductility of the L12 phase. Analysis of the phase equilibrium, phase structure and microstructures of the as-cast and heat-treated alloys were conducted to gain some clues for the further optimization of the compositions, microstructures and processing.
Key words: Co-Ni-Al-Ti quaternary system; L21-type (Co, Ni)2AlTi; L12-type (Co, Ni)3(Al, Ti); intermetallics