51. Microstructure evolution and phase transformation kinetics of low cost Ti-35421 titanium alloy during continuous heating
- Author
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Can Ding, Xin Li, Hong-Yu Zhu, Fu-Wen Chen, Feng Li, and Hui Chang
- Subjects
Ti-35421 alloy ,Dilatometry ,Phase transformation ,Microstructure evolution ,Kinetics ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The thermal expansion behavior, microstructure evolution and β → ωiso phase transformation kinetics of the low cost Ti–3Al–5Mo–4Cr–2Zr–1Fe (Ti-35421, wt.%) titanium alloy during continuous heating have been investigated by using dilatometric (DIL) method. The results revealed that corresponding transformation sequence can be verified as β → ωiso, β + ωiso → α + β, β → α and α → β using TEM and SEM analysis during the heating process. The microstructure and local composition distribution was detected by STEM mapping. The phase transition curve exhibited a typical S-type pattern, indicating the phase transformation was controlled by the nucleation and growth mechanism. It was found that the S-curve shifted to a higher temperature and the phase transition interval became shorter as the heating rate increased. Furthermore, the average activation energy required for the β → ωiso phase transition was calculated by Kissinger–Akahira–Sunose (KAS) equation is about 90.21 kJ/mol. The Avrami exponent n in the Kolmogorov–Johnson–Mehl–Avrami (KJMA) model was used to study the nucleation growth mechanism of the ω phase during continuous heating. The exponent n can be divided into three stages: the initial phase transition (0.02
- Published
- 2021
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