The Paton Welding Journal, 2026, №07

2026 №07 (04)

DOI of Article 10.37434/tpwj2026.07.05

2026 №07 (06)

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The Paton Welding Journal, 2026, #7, 26-33 pages

Effect of vacuum annealing on the structure of high-temperature two-phase titanium (α+β)-alloy

V.Yu. Bilous¹, E.L. Vrzhizhevskyi¹, R.V. Selin¹, L.M. Radchenko¹, S.L. Antoniuk²

¹E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: belousvy@gmail.com
²SC “O.K.Antonov ANTK”, 1 Mriya Str., 03062, Kyiv, Ukraine

Abstract
High-temperature two-phase (α+β) titanium alloys can exhibit high performance characteristics when used in aircraft engines. To expand the scope of application or to repair components made of the two-phase VT9 alloy, it is advisable to consider the possibility of using vacuum annealing to treat blanks or components after machining or welding. This study investigated the effect of vacuum annealing at 950 °C on the microstructure of sheets made of the VT9 titanium (α+β) alloy. Sheets of the VT9 titanium (α+β) alloy, 10 mm thick, were subjected to vacuum annealing at 950 °C for 1 hour and then cooled with the furnace. The microstructure of the samples of the heat-treated two-phase (α+β) titanium alloy VT9 in the as-received condition is homogeneous, finely dispersed and consists of α-phase particles with a thickness of 2–4 μm and a length of 2–20 μm. The microstructure of the metal samples after vacuum annealing followed by cooling with the furnace is homogeneous and consists of α-phase particles with a thickness of 2–6 μm and a length of up to 20 μm. An increase in the size of the α-phase is observed, associated with its coagulation process. Vacuum annealing at 950 °C led to a decrease in the number of dispersed particles in the metal structure and an increase in the size of α-phase particles due to coagulation during slow cooling. The amount of the β-phase in the high-temperature (α+β) titanium alloy VT9 decreases to 15–22 %. Such structural changes can lead to a decrease in the strength properties of the alloy and an increase in its impact toughness, which contributes to improved performance characteristics of components made of the VT9 alloy.
Keywords: titanium alloy, two-phase (α+β) alloys, microstructure, vacuum annealing, α-phase, β-phase

Received: 10.04.2026
Received in revised form: 11.05.2026
Accepted: 13.07.2026

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Suggested Citation

V.Yu. Bilous, E.L. Vrzhizhevskyi, R.V. Selin, L.M. Radchenko, S.L. Antoniuk (2026) Effect of vacuum annealing on the structure of high-temperature two-phase titanium (α+β)-alloy. The Paton Welding J., 07, 26-33. https://doi.org/10.37434/tpwj2026.07.05

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