The Paton Welding Journal, 2026, №08

2026 №08 (01)

DOI of Article 10.37434/tpwj2026.08.02

2026 №08 (03)

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The Paton Welding Journal, 2026, #8, 13-22 pages

Microstructure and phase composition of joints of cast and wrought nickel superalloys produced by friction welding

I.V. Ziakhor, A.M. Levchuk

E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: zyakhor2@ukr.net

Abstract
For domestic manufacturers of aviation gas turbine engines (GTEs), the development of efficient technologies for welding nickel superalloys remains an important challenge, particularly for friction welding of “disk‒blade” (blisk-type) components. The paper presents the results of a study on the formation of dissimilar joints between the cast VZhL12U alloy and the wrought EI698VD alloy produced by friction welding. Experimental methods were used to investigate the influence of friction welding process parameters and postweld heat treatment (HT) conditions on the joint microstructure and the nickel morphology of strengthening phase particles, including carbides and the γ′-phase. The experiments were carried out on superalloy specimens with a diameter of 24 mm. A hybrid friction welding technology was applied with varying durations of rotation braking during the forging stage in the range of tbr = 0.3‒3.0 s. It was established that an increase in tbr significantly affects structural and phase transformations in the thermomechanically affected zone (TMAZ) of the joints. In particular, at tbr = 3.0 s, both the secondary dispersed γ′-phase particles and the thermally stable primary eutectic γ′eut-phase on the side of the cast VZhL12U alloy dissolved during the forging stage. A heat treatment mode was determined that ensures restoration of the γ′-phase particle morphology on the side of the EI698VD alloy and eliminates regions of reduced microhardness within the joint zone. The phenomenon of an anomalous coarsening of dispersed γ′-phase particles in the TMAZ of the VZhL12U alloy after a three-stage HT (according to the specifications for EI698VD alloy) was also observed.
Keywords: nickel superalloys, friction welding, joints, microstructure, heat treatment, γ′-phase, carbides, microhardness

Received: 02.04.2026
Received in revised form: 14.04.2026
Accepted: 28.07.2026

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Suggested Citation

I.V. Ziakhor, A.M. Levchuk (2026) Microstructure and phase composition of joints of cast and wrought nickel superalloys produced by friction welding. The Paton Welding J., 08, 13-22. https://doi.org/10.37434/tpwj2026.08.02

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