Microstructure of the Advanced Titanium Alloy VT8M-1 Subjected to Rotary Swaging
Grigory S. Dyakonov,
Tatyana V. Yakovleva,
Sergei Y. Mironov,
Andrey G. Stotskiy,
Iulia M. Modina,
Irina P. Semenova
Affiliations
Grigory S. Dyakonov
Laboratory of Multifunctional Materials, Ufa University of Science and Technology, 32 Zaki Validi st., 450076 Ufa, Russia
Tatyana V. Yakovleva
Laboratory of Multifunctional Materials, Ufa University of Science and Technology, 32 Zaki Validi st., 450076 Ufa, Russia
Sergei Y. Mironov
Laboratory of Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod National Research University, 85 Pobeda str., 308015 Belgorod, Russia
Andrey G. Stotskiy
Laboratory of Multifunctional Materials, Ufa University of Science and Technology, 32 Zaki Validi st., 450076 Ufa, Russia
Iulia M. Modina
Laboratory of Multifunctional Materials, Ufa University of Science and Technology, 32 Zaki Validi st., 450076 Ufa, Russia
Irina P. Semenova
Laboratory of Multifunctional Materials, Ufa University of Science and Technology, 32 Zaki Validi st., 450076 Ufa, Russia
In this study, the microstructural behavior of the advanced Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn-0.15Si (VT8M-1) alloy during rotary swaging (RS) was investigated. VT8M-1 has increased heat resistance and is considered a replacement for the Ti-6Al-4V alloy. It was shown that, during RS, the evolution of the primary a phase is characterized by the formation of predominantly low-angle boundaries according to the mechanism of continuous dynamic recrystallization. The density of low-angle boundaries increases three times: from 0.38 µm−1 to 1.21 µm−1 after RS. The process of spheroidization of the lamellar (a + b) component is incomplete. The average size of globular a and b particles was 0.3 μm (TEM). It is shown that the microstructures after RS (ε = 1.56) and equal-channel angular pressing (ECAP) (ε = 1.4) are significantly different. The temperature–velocity regime and the predominance of shear deformations during ECAP contributed to a noticeable refinement of the primary a-phase and a more complete development of globularization of the lamellar (a+b) component. EBSD studies have shown that RS leads to the formation of a structure with a higher density of low- and high-angle boundaries compared to the structure after ECAP. The results are useful for predicting alloy microstructure in the production of long rods that are further used in forging operations.
