1. Homogenizing the composition of in-situ fabricated Ti2AlNb-based alloy via manipulating the droplet transfer mode of twin-wire arc additive manufacturing.
- Author
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Yu, Zeyang, Li, Zixiang, Guo, Yueling, Fu, Rui, Xu, Tianqiu, and Liu, Changmeng
- Subjects
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ALLOYS , *MECHANICAL alloying , *DROPLETS , *TENSILE strength , *HIGH temperatures - Abstract
The twin-wire arc additive manufacturing (TWAAM) technology is an effective method for the in-situ fabrication of Ti 2 AlNb-based alloys relative to conventional cast and wrought routes. However, composition segregation is still challenging in the field of in-situ TWAAM. To homogenize the chemical composition, here we proposed a novel single droplet pre-alloying transfer mode of TWAAM based on the original droplet transfer mode of double wires directly fed into the molten pool. The designed nominal composition of Ti-25Al-23Nb was set as the target alloy. The as-printed parts were investigated systematically. The results showed that this unique droplet transfer mode could not only improve the forming accuracy but also effectively mitigate the composition segregation. In addition, the inconsistency of microstructure caused by the composition segregation was successfully solved by this mode and appears a fully lamellar microstructure. The improvement of composition uniformity played a positive role in enhancing the mechanical properties of the alloy, in which the tensile strength of room and high temperature were improved by 76.8% and 74.1% respectively compared with our previous research. This work is of great significance to alleviate the composition segregation of intermetallics and further promote the in-situ TWAAM fabrication of Ti 2 AlNb-based alloys. • The composition segregation that challenges the Ti 2 AlNb-based alloy in-situ fabricated by twin-wire arc additive manufacturing (TWAAM) was successfully mitigated by a novel single droplet pre-alloying transfer mode. • This single droplet pre-alloying transfer mode also promotes the forming stability and accuracy during the TWAAM process. • The improvement of composition uniformity played a positive role in solving the inconsistency of microstructure and enhancing the mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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