Simultaneously achieving exceptional and heat treatment insensitive strength-ductility synergy in an α+β titanium alloy via tailoring silicide and heterogeneous α precipitates

Jinhua Dai, Bin Tang, Chuanyun Wang, Yurong Fan, Beibei Wei, Jiaqi Wu, Yilei Wang, Xiaofei Chen, Xiang Zhang, Yiheng Han, Wentao Chen, Jinshan Li, Pingxiang Zhang

科研成果: 期刊稿件文章同行评审

摘要

The development of cost-effective titanium alloys with outstanding mechanical properties has always been a primary concern of the modern aerospace industry. However, the intrinsic sensitivity of their α precipitates to heat treatments proliferates the manufacturing costs to achieve desirable strength and ductility, especially in engineering occasions. In current work, a silicide-containing α+β Ti-5Al-7.5V-0.5Mo-0.5Zr-0.5Si (TC5751S) alloy has been evidenced to exhibit advanced mechanical properties with reduced sensitivity to heat treatments. It is noted that more nano-scale secondary α (αs) precipitate with a simultaneous dissolution in micron-scale primary α (αp) and (Ti, Zr)5Si3 silicides in the current alloy as the solution temperature increases. However, this alloy shows excellent and stabilized strength-ductility synergy in all cases (ultimate tensile strength: 1335±30 MPa, yield strength: 1245±30 MPa, fracture strain: 9.6 %±0.5 %) irrespective of the aforementioned variations in the microstructure. This stabilized strength and ductility of TC5751S are rationalized based on the compensation mechanisms between the contributions from silicide and heterogeneous α precipitates. The quantitative analysis unveils that the increased αs/β phase boundary strengthening (σPB) is approximately offset by the decrease in silicide strengthening (σsilicide) due to silicide dissolution with increasing solution temperatures, leading to the strength of TC5751S in a dynamic equilibrium state. Simultaneously, the dissolution of silicides reduces the cracking tendency and complements the ductility loss due to αp reduction and αs precipitation, leading to the ductility insensitive to heat treatments. Therefore, the compensating role of silicides to the effects of heterogeneous α precipitates on both the strength and ductility of titanium alloys has been well-verified in our work, providing a novel pathway to the development of high-performance titanium alloys friendly to processing strategies.

源语言英语
页(从-至)51-66
页数16
期刊Journal of Materials Science and Technology
236
DOI
出版状态已出版 - 20 11月 2025

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