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...

At the present time the use of welded assemblies and structures of high-strength titanium alloys (s t .≥ 1100 MPa) is widened. Moreover, the strength characteristics of welded joints should be at the level of characteristics of alloys. For load-carrying elements of aircrafts of AN type, high-strength two-phase (a + b)-titanium VT22 alloy is used. The aim of the work was the investigation of the influence of reducing the degree of weld metal alloying on its strength characteristics. For this purpose a completely new filler material, namely titanium flux-cored wire, for argon arc welding of VT22 alloy was developed. Despite the decrease in the degree of alloying of weld metal, its strength reaches 1121.5 MPa after the standard heat treatment, which is higher than the level of strength of the base metal (1057.5 MPa). Moreover, the impact toughness amounts to 70-75 % of the base metal impact toughness. 15 Ref., 4 Tables, 6 Figures.

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The welded joints of high-strength titanium alloys, produced using arc welding, have, as a rule, unsatisfactory values of mechanical properties, especially those of ductility in the as-welded state as compared to the base metal. In the work the effect of thermal welding cycle, type of filler metal and the post-weld heat treatment on the structure and properties of welded joints of two-phase high-alloyed titanium alloys having σ t > 1000 MPa, were evaluated. The properties and structure of welded joints of high-strength titanium alloys VT23, T110 and experimental alloy Ti-6.5A1-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr, made by argon arc welding applying the filler wires, differing by their composition from the base metal, were studied. It is rational to produce the joints of complex-alloyed titanium alloy Ti-6.5A1-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr using argon arc welding applying filler wire VT1-00sv at modes, providing the through penetration and the content of wire components in the weld metal at level of 10 % in combination with the subsequent high-temperature annealing. 6 Ref., 1 Table, 6 Figures. K e y w o r d s : titanium alloys, argon arc welding, filler wire, properties, structure

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