Modern two-phase high-alloyed alloys based on titanium are characterized by a high specific strength. The thermal cycle of welding results in change of structures of weld and HAZ metal and also in deterioration of mechanical characteristics of the joint. In the work the properties of welded joints of titanium alloys VT23, T110 and high-alloyed alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr, produced using electron beam and argon arc welding, were evaluated. In weld and HAZ metal of the TIG-welded joints of alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr, the structure is formed with a predominance of metastable β-phase and low values of strength and impact toughness, the joints require postweld high-temperature annealing at temperature of not less than 900 °C. The joints of VT23 alloy have high values of strength and impact toughness. High-strength titanium alloy T110 is characterized by good weldability in EBW and TIG welding, has high values of impact toughness of weld metal and HAZ after annealing, the strength of welded joints is at the level of 0.9 of base metal strength. 7 Ref., 2 Tables, 4 Figures. K e y w o r d s : titanium alloys, tungsten-electrode argon-arc welding, electron beam welding, propertiesModern two-phase high-alloyed alloys based on titanium are characterized by a high specific strength, nowadays the growing attention is paid to widening the use of welded structures and assemblies of high-strength titanium alloys (σ t > > 1100 MPa) [1,2]. The weldability of twophase high-alloyed titanium alloys, the use of which may provide the greatest reduction in mass of the structure, is significantly worse than that of low-alloyed alloys, and according to this indicator they are inferior even to some highstrength steels, therefore, when developing new titanium alloys, a significant attention is paid to the possibility of producing welded joints with strength of not less than 0.90-0.95 of base material strength.The aim of the work is to evaluate the properties of welded joints of both industrial and also new two-phase high-titanium alloys having σ t > > 1000 MPa (Table 1), developed at the E.O.Paton Electric Welding Institute, as well as to study the influence of thermal cycle of welding and postweld heat treatment on structural and phase transformations in weld metal and HAZ.In the course of investigations the properties of welded joints, produced by electron beam welding (EBW) and argon arc welding with tungsten electrode (TIG) without using filler metal were compared.The joints of high-strength titanium alloy VT23 [3] were made of 10 mm thick plates, joints of titanium alloy of grade T110 were made of 7 mm thick plates. The high-grade alloy of T110 system Ti-5.5Al-1.2Mo-1.2V-4Nb-2Fe-0.5Zr was developed at the PWI together with the O.K. Antonov ASTC [4]. It contains the following alloying elements, wt.%: 5-6 Al, 3.5-4.8 Nb, 0.8-1.8 Mo, 0.8-2 V, 1.5-2.5 Fe, 0.3-0.8 Zr. Alloy T110, as compared to VT23, has a higher resistance to the formation of fatigue cracks and according to the number of service characteristics...

определены технологические режимы проведения термодеформационной обработки слитков электронно-лучевой плавки нового сплава Т120. Проведены работы по получению экспериментальной серии деформированных заготовок из слитков диаметром 150 мм нового высокопрочного сплава. После проведенной деформационной обработки исследована микроструктура сплава Т120. определено, что структура титанового сплава Т120, полученного способом ЭЛП, после прокатки состоит из равноосных полиэдрических первичных β‫ـ‬зерен, а внутризеренная структура представлена α‫ـ‬ и β‫ـ‬фазами, причем α‫ـ‬фаза имеет пластинчатую морфологию. Установлено, что при проведении деформационной обработки на поверхности листов образуется окисный, а под ним приповерхностный альфированный слой толщиной до 0,5 мм. исследовано влияние термической обработки деформированных полуфабрикатов на структуру и свойства металла и установлены режимы, которые обеспечивают оптимальное сочетание прочности и пластичности для сплава Т120. Для достижения максимальной пластичности заготовки сплава Т120 целесообразно подвергать отжигу при температуре 900 о С, в результате чего в металле формируется внутризеренная (α + β)-структура с толщиной α-пластин 1,0...1,5 мкм. При этом значение ударной вязкости составляет KCV = 12…14 Дж/см 2 при относительном удлинении δ s = 12 %. библиогр. 9, табл. 2, ил. 5. К л ю ч е в ы е с л о в а : электронно-лучевая плавка; титановый сплав; деформационная обработка; термическая обработка; структура; свойства

Analysis of the TIG-welding impact on the structure and mechanical properties of pseudo-β titanium alloy VT19 welded joints, obtained with different welding speed, different filler wire amount in welded joint, with and without flux layer. Microstructure of obtained welded joints were investigated. Using welded joints microsections approximate amount of β-phase in different parts of welds have been obtained. Mechanical properties of the obtained welded joints were analyzed and dependency of tensile strength and amount of β-phase were build.

As intensive work is underway in leading material science centers in the USA, EU, Russia, and China, both to modernize existing titanium alloys and to create new ones, the E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine developed titanium alloys T110 (Ti-5.5Al-1.2Mo-1.2V-4Nb-2Fe-0.5Zr system) and T120 (Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr system), which according to their characteristics, belong to the group of modern two-phase high-alloyed alloys characterized by high strength and good ductility. With more and more attention is being paid to the expansion in the usage of welded structures and assemblies of high strength titanium alloys with UTS ≥ 1100 MPa, there’s urgent need in studying best ways to obtain welded joints from such alloys. The weldability of two-phase high-alloyed titanium alloys, the use of which can give big reduction in structural weight, is significantly worse than low-alloyed alloys, therefore for a new alloy it is necessary to ensure the possibility of obtaining welded joints with a strength of at least 90% compared to the strength of base material. The aim of this work is to study the influence of the welding thermal cycle and reducing of weld metal alloying degree on the structure and mechanical properties of welded joints of high-strength titanium alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr with tensile strength more than 1200 MPa, as well as assessment of it welded joints properties in comparison with other high-strength titanium alloys.

Analysis of the electron beam welding and different modes of heat treatment such as local heat treatment, furnace annealing, slow speed cooling, water quenching and aging impact on the structure and mechanical properties of pseudo-β titanium alloy VT19 welded joints. Microstructure of obtained welded joints in the states after welding and heat treatment were investigated. Using welded joints microsections approximate amount of β-phase has been obtained. Mechanical properties of the welded joints were analyzed and dependency of tensile strength and amount of β-phase were build.