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INCOLOY 925 is a high-performance nickel-based alloy widely used in industrial applications where both high strength and excellent corrosion resistance at elevated temperatures are mandatory. This study investigates the hot deformation by forging and, heat treatment by solution annealing and ageing behaviour of INCOLOY 925 alloy. The hot deformation by forging was performed in two stages, first stage at 1075°C with an applied deformation degree of 60% followed by a second deformation stage at 975°C with an applied deformation degree of 25%. The heat treatment processing was performed after hot deformation and comprised of two stages, a solution annealing, at 1010°C with a soaking duration of 1h and air quenching, followed by a double ageing treatment, at 740°C with a soaking duration of 8h followed by a soaking at 620°C with a duration of 17h. The microstructural evolution during thermomechanical processing was performed using XRD and SEM-EBSD investigation techniques, while the mechanical behaviour was investigated using tensile testing. Data referring to microstructural constituents, grain size (D) and mechanical properties was obtained and analysed. In all processed stages the microstructure consists of γ-phase, γ’-phase and MC (M: Cr, Mo, …) carbides. Comparing the mechanical properties obtained during different thermomechanical processing stages showed that the solution annealing favours ductility properties (i.e. elongation to fracture) in comparison with the hot-deformation, while the ageing treatment favours strength properties (i.e. ultimate tensile strength, yield strength) in comparison with the hot-deformation and the solution annealing.
Acknowledgements. This work was supported by a grant from the Ministry of Research, Innovation and Digitization (Romania), CCCDI—UEFISCDI, project number PN-IV-P7-7.1-PTE-2024-0364, within PNCDI IV.