Achieving equiaxed and lamellar TiAl alloys via cold-cathode electron beam additive manufacturing with dual-wire synergistic control
TiAl alloy, renowned for its high temperature resistance while maintaining lightweight properties, serves as a crucial structural material for hot-end components. However, the widespread application of additive manufacturing (AM) for TiAl alloys is constrained by their limited ductility. To enable t...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-01-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S223878542402934X |
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| Summary: | TiAl alloy, renowned for its high temperature resistance while maintaining lightweight properties, serves as a crucial structural material for hot-end components. However, the widespread application of additive manufacturing (AM) for TiAl alloys is constrained by their limited ductility. To enable the engineering-scale production of TiAl alloys with enhanced strength and ductility, this study introduces advancements in the heat source, material composition, and deposition processes. The characteristics of the cold-cathode electron beam heat source were used to manufacture low-cost in-situ alloyed TiAl alloys through wire-fed electron beam additive manufacturing. Mo, Zr, and Si elements were introduced into the TiAl alloy, and precise thermal control allowed the separated twin wires to simultaneously form a stable co-molten pool, and the specimens with good appearance and no internal microcracks and pores were obtained. Furthermore, a detailed comparison between Ti48Al alloy and Ti48Al1Mo0.45Zr0.3Si alloy was carried out, focusing on aspects such as grain morphology, chemical composition homogeneity, phase constitution, and mechanical properties. The influence of dual-wire synergistic control on process stability, microstructure evolution, and strengthening mechanisms was discussed. The results show that the cold-cathode electron beam heat source under low vacuum and the co-molten pool mode reduce aluminum evaporation and promote element mixing through layer-by-layer temperature control and remelting. Compared to the lamellar microstructure of Ti48Al alloy, the Ti48Al1Mo0.45Zr0.3Si alloy exhibits a dual-γ phase microstructure, consisting of fine lamellar colonies and equiaxed γ grains. This modification led to a 90% and 150% increase in elongation at room temperature and 650 °C, respectively. These findings offer important insights into enhancing the performance of TiAl alloys through cost-effective alloying strategies. |
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| ISSN: | 2238-7854 |