Effects of Y and Nb on the Microstructure and Mechanical Properties of Rapidly Solidified TiAl Alloys

Abstract:

The effects of Y and Nb on the microstructure and mechanical properties of rapidly solidified TiAl alloys were investigated. Results show that the rapidly solidified TiAl alloys with various Y contents are of equiaxed microstructure, and composed mainly of α2 and a few amount of γ phase. With Y content increasing, the volume fraction of γ phase is increased and the microstructure of the TiAl alloys is gradually refined. The alloys with various Nb contents show lamellar structure with reduced interlamellar spacings of 15-17 nm and massive structure. γ and α2 are also the two main phases for rapidly solidified TiAl alloys with various Nb addition. The hardness of rapidly solidified TiAl alloys is higher than that of the conventionally cast TiAl alloys