This study investigates the effect of deformation temperature, strain rate, and strain on the deformation behavior above and below the beta (β) transus temperature (Tβ), as well as the alpha (α) + β microstructure evolution, in Ti-17 alloy during deformation and subsequent cooling to room temperature. Dynamic recovery is the dominant restoration mechanism of the β matrix during hot deformation above and below the Tβ, which leads to the formation of subgrain structure under applied conditions. During deformation at temperatures less than the Tβ, the α phase precipitates at β grain boundaries initially in a globular or film shape (GBα), followed by the formation of Widmanstätten α (Wα) plates from the GBα and inside the β grains. The α precipitation kinetics is accelerated by increasing the deformation strain during deformation at temperatures less than the Tβ. Even at temperatures greater than the Tβ, deformation is found to induce α-phase precipitation at β boundaries. Further, α-phase precipitation occurs during slow cooling after deformation, whereas greater deformation strain leads to a decrease in the total α-phase fraction because the enrichment of Mo and Cr and the depletion of Al in the β phase by the formation of Wα at higher temperatures stabilizes the β phase and thus suppresses the subsequent β → α transformation during cooling.
|ジャーナル||Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science|
|出版ステータス||Published - 2021 7|
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