1. Static coarsening behavior of a pre-deformed Ti2AlNb-based alloy during heat treatment.
- Author
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Zhang, Hongyu, Li, Chong, Ma, Zongqing, Huang, Yuan, Yu, Liming, and Liu, Yongchang
- Subjects
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OSTWALD ripening , *HEAT treatment , *SCANNING transmission electron microscopy , *KIRKENDALL effect , *ALLOYS , *TRANSMISSION electron microscopy - Abstract
Microstructure evolution, static coarsening mechanism and coarsening kinetics of a pre-deformed Ti 2 AlNb-based alloy during aging at 945 °C and 970 °C were investigated in this study. The corresponding microstructures were characterized by scanning electron microscopy and transmission electron microscopy. The results show that the pre-deformed alloy exhibited different morphologies aged at 945 °C and 970 °C. When the alloy was aged at 970 °C, the coarsening mechanism of the O precipitates was mainly controlled by the Ostwald ripening mechanism at first aging stage; after that, it was controlled by the boundary splitting mechanism and termination migration mechanism. Due to the difference in interface energy between the terminals and the long-axis direction of the O lath, diffusion process of solute atoms leads to the coarsening and fragmenting of O lath. The dimension of the O precipitates in the studied alloy continued to grow with the prolonged time during aging at 945 °C or 970 °C while the coarsening rate decreased. The static coarsening kinetic of the studied alloy was established in term of the modified Lifshitz-Slyozov-Wagner (LSW) theory. Static coarsening behavior of the pre-deformed alloy was mainly controlled by bulk diffusion at 945 °C and interfacial diffusion at 970 °C, respectively. • The thickness of O precipitates increased with aging temperature and time. • The microstructure consisted of lamellar O at 945 °C and changed from spherical to lath with aging time at 970 °C-aging. • Static coarsening behavior was controlled by Ostwald ripening, boundary splitting and termination migration mechanism. • Coarsening kinetics of the studied alloy can be established according to modified LSW theory. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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