Rapidly solidified Ni3Al ribbons and wires were prepared in order to examine the relationship between antiphase domain structure and ductility. As-rapidly solidified ribbons of Ni-rich binary and ternary Ni3Al alloys show fine antiphase domain structure and exhibit no ductility, except for Ni-22A1-20Co. The ribbons annealed at temperatures higher than 1173K, however, become ductile, although annihilation of antiphase domains and grain growth occurred. This indicated that the ductility of Ni3Al ribbons was not directly related to antiphase domain structure but was determined by alloy composition. Melt-spun Ni3Al wires consist of a dendritic structure as usually seen in conventional castings, suggesting that the cooling rate during solidification of molten stream was not so high as to suppress the development of dendrites. It was found that the microstructure of the melt-spun Ni3Al wires was quite different from that of the rapidly solidified Ni3Al ribbons.

Relationship between the APD Structure and Ductility of Rapidly Solidified Ni3Al Alloys. Chiba, A., Hanada, S.: Intermetallics, 1996, 4[1], 55-9