Back to articleAlthough transverse microstructures of the directionally solidified Ni-33Al-31Cr-3Mo base alloy exhibited lamellar eutectic colonies consisting of alternating NiAl and Cr,Mo plates, the addition of a fifth element resulted in the formation of a cellular microstructure. Four different types of lamellar structures were found within the cells due to the addition of these fifth elements. These include radial (a, g, and i), planar (b, e, f, and h), nautilus spiral (c), and shell (d) eutectic microstructures. The addition of 0.25 at.% Co, 0.5 to 1.0 Fe, 0.25 Hf, 0.25 to 1.0 Nb, 0.25 to 1.0 Si, and 0.25 to 1.0 Ta also resulted in the formation of NiAl dendrites (f). Additions of 0.5 to 1.0 Cu, 0.25 to 1.0 Hf, 1.0 Mn, 0.25 to 1.0 Nb, 0.5 to 1.0 Re, 0.5 to 1.0 Si, 0.25 to 1.0 Ta, 0.25 to 1.0 Ti, and 0.25 to 0.5 Zr caused the formation of broad intercellular regions (b, g, h, and i). Third phases (i) formed with the addition of 1.0 Hf, 1.0 Nb, 1.0 Ta, and 1.0 Zr.
Last updated: June 2002
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