OBRABOTKAMETALLOV Vol. 27 No. 2 2025 technology Conclusion The effect of GTAW modes on the quality of welded joints made of the Ti2AlNb-based alloy Ti–Al– Nb–(Zr, Mo)–Si alloy is studied. Based on the results obtained in this work, the following conclusions are drawn: – A defect-free weld is formed in welding modes at direct and pulsed currents in the range of 80–115 A and with a gas flow rate of 12–15 L/min. At lower welding currents, incomplete penetration (lack of fusion) was detected, while at higher currents, burn-through occurred. – The welds, depending on the welding modes, have the following microstructure: elongated, large dendrites with a size of 0.23–1.39 mm in the center of the weld; and globular β-grains with a size of 130–190 μm in the root area of the weld. The main volume of the liquid pool is concentrated near the impact of the welding arc. Therefore, columnar dendrites are formed in the central and upper part of the weld, where the maximum heat removal occurs. – Mechanical testing of Ti–Al–Nb–(Zr, Mo)–Si alloy welded joints showed a high strength level of ≈ 90 % of the base metal strength when using the pulsed welding mode (σu = 1100 MPa, δ = 1.1 %, 340–380 HV0.2) and not less than 80 % when using direct current modes (σu = 1070 MPa, δ = 1.49 %, 335–390 HV0.2). References 1. ZhaoQ., SunQ., Xin S., ChenY.,WuC.,WangH., Xu J.,WanM., ZengW., ZhaoY. High-strength titaniumalloys for aerospace engineering applications: a review on melting-forging process. Materials Science and Engineering: A, 2022, vol. 845, p. 143260. DOI: 10.1016/j.msea.2022.143260. 2. Marin E., Lanzutti A. Biomedical applications of titanium alloys: a comprehensive review. Materials (Basel), 2024, vol. 17 (2), p. 114. DOI: 10.3390/ma17010114. 3. Ezugwu E.O., Wang Z.M. Titanium alloys and their machinability – a review. Journal of Materials Processing Technology, 1997, vol. 68 (3), pp. 262–274. DOI: 10.1016/S0924-0136(96)00030-1. 4. Pasang T., Tao Y., Azizi M., Kamiya O., Mizutani M., Misiolek W. Welding of titanium alloys. MATEC Web of Conferences, 2017, vol. 123, pp. 1–8. DOI: 10.1051/matecconf/201712300001. 5. Veiga C., Davim J.P., Loureiro A. Properties and applications of titanium alloys: a brief review. Reviews on Advanced Materials Science, 2012, vol. 32 (2), pp. 133–148. 6. Kim Y.-W., Dimiduk D.M. Progress in the understanding of gamma titanium aluminides. JOM, 1991, vol. 43, pp. 40–47. 7. ShagievM.R., Galeyev R.M., Valiakhmetov O.R. Ti2AlNb-based intermetallic alloys and composites. Materials Physics and Mechanics, 2017, vol. 33 (1), pp. 12–18. DOI: 10.18720/MPM.3312017_2. 8. Nandy T.K., Banerjee D. Creep of the orthorhombic phase based on the intermetallic Ti2AlNb. Intermetallics, 2000, vol. 8 (8), pp. 915–928. DOI: 10.1016/S0966-9795(00)00059-5. 9. Dadé M., Esin V.A., Nazé L., Sallot P. Short- and long-term oxidation behaviour of an advanced Ti2AlNb alloy. Corrosion Science, 2019, vol. 148, pp. 379–387. DOI: 10.1016/j.corsci.2018.11.036. 10. Xu J., He L., Su H., Zhang L. Tool wear investigation in high-pressure jet coolant assisted machining Ti2AlNb intermetallic alloys based on FEM. International Journal of Lightweight Materials and Manufacture, 2018, vol. 1 (4), pp. 219–228. DOI: 10.1016/j.ijlmm.2018.08.007. 11. Chen W., Li J.W., Xu L., Lu B. Development of Ti2AlNb alloys: opportunities and challenges. AM&P Technical Articles, 2014, vol. 172 (5), pp. 23–27. DOI: 10.31399/asm.amp.2014-05.p023. 12. Panov D.O., Naumov S.V., Sokolovsky V.S., Volokitina E.I., Kashaev N., Ventzke V., Dinse R., Riekehr S., Povolyaeva E.A., Alekseev E.B., Nochovnaya N.A., Zherebtsov S.V., Salishchev G.A. Cracking of Ti2AlNb-based alloy after laser beam welding. IOP Conference Series: Materials Science and Engineering, 2021, vol. 1014, p. 012035. DOI: 10.1088/1757-899X/1014/1/012035. 13. Li Y.-J., Wu Ai-P., Li Q., Zhao Y., Zhu R.-C., Wang G.-Q. Mechanism of reheat cracking in electron beam welded Ti2AlNb alloys. Transactions of Nonferrous Metals Society of China, 2019, vol. 29 (9), pp. 1873–1881. DOI: 10.1016/S1003-6326(19)65095-8.
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