| Raipdly solidified powders of Ni-6.61%Al-3.35 %Ti-0.019%C and Ni-6.49%Al-1.98%Ti-5.34%Mo-0.028%B-0.33%Fe-0.084%C were investigated ; microstructures of the powders had been investigated at as-rapidly-solidified state and after annealing at 800℃ and 1,000℃. After rapid solidification by Ar gas atomization, the microstructure of the powder particles showed dendritic or equiaxed poly-grain morphology irrespective of the particle size. The elongated γ` phase has been precipitated next to grain boundaries in the direction perpendicular to the grain boundary, and ultrafine γ` particles were dispersed within the grains. When the alloy powders were annealed at 800℃ and 1,000℃, the elongated γ` phase had grown to an irregular shape, and the ultrafine γ` particles inside the grains had grown to a cubic shape. |
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