OBRABOTKAMETALLOV Vol. 24 No. 4 2022 technology Fig. 8. FSW tool made of heat-resisted alloy ZhS6U: a – before welding; b – after welding Conclusion The performed research showed that during friction stir welding of high-strength Ti-4Al-3Mo-1V alloy, an increase in the axial force leads to an increase in the degree of deformation of the welded material structural elements, which positively affects the strength of the stirring zone. However, it also leads to softening of a welded joint, since it substantially affects the structural-phase state of the thermo-mechanically affected zone, which is the least durable. A low thermal conductivity of titanium alloys provides the formation of a narrow zone of thermomechanical affection and also contributes to the degradation of the strength properties of the welded joint with an increase of its length, since the heat accumulation contributes to the growth of large particles of secondary phases in the zone of thermomechanical affection. Strengthening of the welded joint is not related to the failure factor of the welding tool made of heat-resistant alloy ZhS6U, which is resistant to the loads of the welding process and can be effectively used in the processes of friction stir welding of titanium alloys. References 1. Paranthaman V., Dhinakaran V., Swapna Sai M., Devaraju A. A systematic review of fatigue behaviour of laser welding titanium alloys. Materials Today: Proceedings, 2021, vol. 19, pt. 1, pp. 520–523. DOI: 10.1016/j. matpr.2020.08.249. 2. Ren D., Jiang Y., Hu X., Zhang X., Xiang X., Huang K., Ling H. Investigation of tensile and high cycle fatigue failure behavior on a TIG welded titanium alloy. Intermetallics, 2021, vol. 132, p. 107115. DOI: 10.1016/j. intermet.2021.107115. 3. Liu F., Chen Y., He C., Wang C., Li L., Liu Y., Wang Q. Very long life fatigue failure mechanism of electron beam welded joint for titanium alloy at elevated temperature. International Journal of Fatigue, 2021, vol. 152, p. 106446. DOI: 10.1016/j.ijfatigue.2021.106446. 4. Gangwar K., Ramulu M. Friction stir welding of titanium alloys: a review. Materials and Design, 2018, vol. 141, pp. 230–255. DOI: 10.1016/j.matdes.2017.12.033. 5. Gao F., Guo Y., Yang S., Yu Y., Yu W. Fatigue properties of friction stir welded joint of titanium alloy. Materials Science and Engineering: A, 2020, vol. 793, p. 139819. DOI: 10.1016/j.msea.2020.139819. 6. Mironov S., Sato Y.S., Kokawa H. Friction-stir welding and processing of Ti-6Al-4V titanium alloy: a review. Journal of Materials Science and Technology, 2018, vol. 34, iss. 1, pp. 58–72. DOI: 10.1016/j.jmst.2017.10.018. 7. Raut N., Yakkundi V., Vartak A. A numerical technique to analyze the trend of temperature distribution in the friction stir welding process for titanium Ti 6Al 4V. Materials Today: Proceedings, 2021, vol. 41, pt. 2, pp. 329–334. DOI: 10.1016/j.matpr.2020.09.336.
RkJQdWJsaXNoZXIy MTk0ODM1