We have been working since 1993 on a series of research projects on friction welding to produce metal joints. Friction welding is a family of process which are solid state joining technologies, in contrast to the more widespread technologies such as Tungsten Inert Gas and Submerged Arc welding where components melted locally at the joint. It uses frictional heat for joining materials together through an intimate contact of a plasticised interface which is generated by this heat.
Friction welded joints are characterised by fewer metallurgical problems than fusion welding, lower residual stresses. They can join materials or dissimilar material combinations which are impossible to weld by conventional fusion techniques. These processes are used in the automotive, marine, aerospace industry among others.
In particular, Linear Friction Welding is being used successfully since the 1990s in aerospace industry applications to attach titanium alloy blades to disks and the subsequent repair of aero engines. Its success lies on its ability to join metal alloys, like those of titanium and nickel superalloys, that cannot be welded with conventional fusion welding techniques. The use of such alloys allowed the production of more powerful aircraft engines, both in military and commercial aircraft.
In addition, Friction Stir Welding has been used extensively since its invention in the 1990s to join aluminium sheets structures in the automotive and marine engineering industry. Its success lies on its ability to join aluminium sheets of various thicknesses economically and reliably.
Our work focuses on experimental and theoretical research on friction welding, and in particular on linear friction welding and friction stir welding. During the course of these years, we have formed strong links with research groups who are active in the research of friction welding technologies. These groups are from the University of Palermo and the University of Naples "Federico II" in Italy, and the Northwestern Polytechnical University in P.R. China.
Our research efforts to date have produced a number of scientific papers on these solid-state joining techniques, out of which are four of the five most referenced papers in the "linear friction welding" category in Scopus (8/2025).
Vairis, A., Frost, M., “High frequency linear friction welding of a titanium alloy”, Wear, 1998 vol.217, no.1, pp.117-131. (289 citations)
Vairis, A., Frost, M., “On the extrusion stage of linear friction welding of Ti 6Al 4V”, Materials Science and Engineering: A, 1999, vol.271, pp.477-484. (183 citations)
Vairis, A., Frost, M., “Modelling the linear friction welding of titanium blocks”, Materials Science and Engineering: A, 2000, vol.292, pp.8-17. (228 citations)
Li, W., Vairis; A., Preuss; M., Ma, T., “Linear and Rotary Friction Welding review”, International Materials Reviews, 2015, no.2, pp. 71-100. (337 citations)
See article on LinkedIn on the linear and rotary friction welding processes.
In detail,
Review Journal papers on Friction Welding
Li, W., Vairis; A., Preuss; M., Ma, T., “Linear and Rotary Friction Welding review”, International Materials Reviews, 2015, vol.61, no.2, pp. 71-100 .
McAndrew, A., Colegrove, P.A., Buhr, C., Flipo, B., Vairis, A., "A literature review of Ti6Al4V linear friction welding", Progress in Materials Science, doi:10.1016/j.pmatsci.2017.10.003
Li, W., Guo, J., Ma, T., Vairis, A., “Numerical Modeling of Linear Friction Welding: A literature review”, China Welding, 2014, vol.23, no.4, pp.1-7.
Patel, V., Li, W.Y., Wang, G., Wang, F., Vairis, A., Niu, P., “Friction Stir Welding of Dissimilar Aluminum Alloy Combinations: State-of-the-Art”, Metals, vol.9, art.270, 2019, doi:10.3390/met9030270.
Vairis, A., “Linear friction welded titanium alloy joints: a brief review of microstructure evolution and mechanical properties”, Welding International, 2022. DOI: 10.1080/09507116.2022.2149366
Selected papers on Friction Welding
Vairis, A., Frost, M., “High frequency linear friction welding of a titanium alloy”, Wear, 1998 vol.217, no.1, pp.117-131.
Vairis, A., Frost, M., “On the extrusion stage of linear friction welding of Ti 6Al 4V”, Materials Science and Engineering: A, 1999, vol.271, pp.477-484.
Vairis, A., Frost, M., “Modelling the linear friction welding of titanium blocks”, Materials Science and Engineering: A, 2000, vol.292, pp.8-17.
Vairis, A., Frost, M., “Design and commissioning of a friction welding machine”, Journal of Materials and Manufacturing Processes, 2006, vol.21, no.8, pp. 766-773.
Vairis, A., “Superplasticity Effects and Strain Rate Dependency in a Material Joining Process”, Journal of Engineering Science and Technology Review, 2008, vol.1, pp.28-32.
Vairis, A., Petousis, M., “Designing experiments to study welding processes: using the Taguchi method”, Journal of Engineering Science and Technology Review, 2009, vol.2, no.1, pp.99-103.
Yamileva, A.M. Medvedev, A.Yu. Nasibullayev, I.Sh., Selivanov, A.S.. Gazizov, R.K , Vairis., A., “A two-parameter 2D-model of the elastic stage of linear friction welding using ANSYS Mechanical finite element analysis programme”, Journal of Engineering Science and Technology Review, 2012, vol.5, no.3, pp.6-9.
Chukalova, A.O., Yamileva, A.M., Nasibullayev, I.Sh., Vairis, A., “The influence of the material parameters varying on dynamics of linear friction welding process”, Vestnik USATU. Ufa, Russia, 2012. vol.16, No 7 (52). pp.128-132. (In Russian)
Fang, F., Li, W.Y., Li, J.L., Vairis, A., “Process parameter analysis of inertia friction welding nickel-based superalloy”, International Journal of Advanced Manufacturing Technology, 2014, vol.71, pp.1909-1918.
Li, W.Y., Wang, F.F., Shi, S.X., Ma, T.J, Li, J.L., Vairis, A., “3D Finite Element Analysis of the Effect of Process Parameters on Linear Friction Welding of Mild Steel”, Journal of Materials Engineering and Performance, 2014, vol.23, pp.4010-4018.
Buffa, G., Cammalleri, M., Campanella, D., Fratini, L., Vairis, A., “Effective Linear Friction Welding Machine Redesign through Process Analysis”, Key Engineering Materials 2014, vol. 622-623, pp.484-491.
Zhang, Z., Li; W., Li; J., Chao; Y.J., Vairis, A., “Microstructure and anisotropic mechanical behavior of friction stir welded AA2024 alloy sheets”, Materials Characterization, 2015, vol.107, pp.112-118.
Bikmeyev, A.T., Gazizov, R.K., Yamileva, A., Vairis., A., Zheleznov, F.O., “On the visualization of joint formation during linear friction welding”, Journal of Engineering Science and Technology Review, 2015, vol.8, no.6, pp.68-72
Fu, Y., Li, W., Yang, X., Ma, T., Vairis, A., “The effects of forging pressure and temperature field on residual stresses in linear friction welded Ti6Al4V joints”,Advances in Manufacturing,2016, DOI 10.1007/s40436-016-0161-6
Wang, X.Y., Li, W., Ma, T., Vairis, A., “Characterisation studies of linear friction welded titanium joints”, Materials and Design, 2017, vol.116, pp.115-126.
Niu,P., Li, W.Y., Yang, X., Vairis,A., “Effects of microstructural asymmetries across friction-stir-welded AA2024 joints on mechanical properties”, Science and Technology of Welding and Joining, 2017, DOI:10.1080/13621718.2017.1328765.
Li,W.Y., Li, N., Yang, X.W., Feng, Y., Vairis,A., “Impact of cold spraying on microstructure and mechanical properties of optimized friction stir welded AA2024-T3 joint”, Materials Science and Engineering, 2017, DOI:10.1016/j.msea.2017.07.003.
Li, N., W.Y. Li, X.W. Yang, Y. Feng, A. Vairis, "An investigation into the mechanism for enhanced mechanical properties in friction stir welded AA2024-T3 joints coated with cold spraying", Applied Surface Science (2018), doi: https://doi.org/10.1016/j.apsusc.2018.01.049visu
Chu, Q., Li, W.Y., Yang, X.W., Shen, J.J., Vairis, A., Feng, W.Y., Wang, W.B.,"Microstructure and mechanical optimization of probeless friction stir spot welded joint of an Al-Li alloy", Journal of Materials Science and Technology (2018)
Su, Y., Li, W.Y., Wang, X., Ma, T.J., Yang, X., Vairis, A., “Linear friction welding of titanium alloys: state-of-the-art and perspectives”, Materials China, vol.36, no.11, pp.852-859.
Su, Y., Li, W.Y., Patel, V., Vairis, A., Wang, X., “Formability of an AA5083 aluminum alloy T-joint using SSFSW on both corners”, Materials and Manufacturing Processes, 2019, 2019, pp.1737-1744. DOI.org/10.1080/10426914.2019.1669799
Wu, D., Li, WY., Gao, YJ., Yang, J., Su, Y., Wen, Q., Vairis, A.,"Effect of an improved pin design on weld formability and mechanical properties of adjustable-gap bobbin-tool friction stir welded Al-Cu aluminum alloy joints", Journal of Manufacturing Processes, 2020, vol.58, pp.1182-1188
Dimopoulos, A.; Vairis, A.; Vidakis, N.; Petousis, M., "On the Friction Stir Welding of Al 7075 Thin Sheets", Metals, 2021, 11, 57. https://doi.org/10.3390/met11010057 (IF:1.704)
Guo, Z., Ma, T., Yang, X., Chen, X., Tao, J., Li, W.Y., Vairis, A., “Linear friction welding of Ti60 near-α titanium alloy: Investigating phase transformations and dynamic recrystallization mechanisms”, Materials Characterization, 2022, vol.194, 112424. DOI: 10.1016/j.matchar.2022.112424 (IF: 4.342) (Q1)
Guo, A., Ma, T., Yang, X., Li, W.Y., Tao, J., Vairis, A., “Thermo-physical simulation of deformation behavior and microstructure evolution for linear friction welding of near-β titanium alloy”, Transactions of Nonferrous Metals Society of China, 2023, vol. 33, pp. 481-493. DOI: 10.1016/S1003-6326(22)66121-1 (IF:3.572) (Q1)
Guo, Z., Ma, T., Yang, X., Li, W.Y., Xu, Q., Li, Y., Li, J., Vairis, A., “Comprehensive investigation on linear friction welding a dissimilar material joint between Ti17(α+β) and Ti17(β): Microstructure evolution, failure mechanisms, with simultaneous optimization of tensile and fatigue properties”, Materials Science and Engineering A, 2024, vol. 909, art.no. 146818. DOI: 10.1016/j.msea.2024.146818 (IF: 6.4) (Q1)
Patsalias, G., Sofias, K., Vairis, A., “Solid-State Welding of Thin Aluminum Sheets: A Case Study of Friction Stir Welding Alloys 1050 and 5754”, Metals, vol.15, 2025, DOI: 10.3390/met15040463. (IF: 2.259) (Q1)