The present study investigates the influence of hot-deformation, above β-transus and different thermal treatments on the microstructural and mechanical behaviour of a commercially available Ti-6246 titanium-based alloy, by SEM (scanning electron microscopy), tensile and microhardness testing techniques. The as-received Ti-6246 alloy was hot-deformed—HR by rolling, at 1000 °C, with a total thickness reduction (total deformation degree) of 65%, in 4 rolling passes. After HR, different thermal (solution—ST and ageing—A) treatments were applied in order to induce changes in the alloy’s microstructure and mechanical behaviour. The applied solution treatments (ST) were performed at temperatures below and above β-transus (α → β transition temperature; approx. 935 °C), to 800 °C, 900 °C and 1000 °C respectively, while ageing treatment at a fixed temperature of 600 °C. The STs duration was fixed at 27 min while A duration at 6 h. Microstructural characteristics of all thermomechanical (TM) processed samples and obtained mechanical properties were analysed and correlated with the TM processing conditions. The microstructure analysis shows that the applied TM processing route influences the morphology of the alloy’s constituent phases. The initial AR microstructure shows typical Widmanstätten/basket-weave-type grains which, after HR, are heavily deformed along the rolling direction. The STs induced the regeneration of α-Ti and β-Ti phases, as thin alternate lamellae/plate-like structures, showing preferred spatial orientation. Also, the STs induced the formation of α′-Ti/α″-Ti martensite phases within parent α-Ti/β-Ti phases. The ageing treatment (A) induces reversion of α′-Ti/α″-Ti martensite phases in parent α-Ti/β-Ti phases. Mechanical behaviour showed that both strength and ductility properties are influenced, also, by applied TM processing route, optimum properties being obtained for a ST temperature of 900 °C followed by ageing (ST2 + A state), when both strength and ductility properties are at their maximum (σUTS = 1279 ± 15 MPa, σ0.2 = 1161 ± 14 MPa, εf = 10.1 ± 1.3%).

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The Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) titanium alloy is categorized as one of α + β titanium alloys group, which plays an important role in the aerospace applications. This study aims to find out the optimal thermomechanical processing route to obtain a good balance of strength, ductility and fracture toughness. The Ti-6246 alloy was hot-deformed at a temperature of 900°C, with a total deformation degree of approximately 60%, and heattreated by a solution treating at temperatures between 800°C -1000°C for 18 minutes. The microstructural evolution, mechanical properties and fractography analysis were investigated. Results revealed that the volume fraction of the primary α (αp) phase decreases progressively until it is completely dissolved with increasing solution temperature; the secondary α (αs) phase increases whereas its width decrease with increasing solution temperature, and also the yield stress and ultimate tensile strength decrease with increasing solution temperature. A good balance of ultimate tensile strength and ductility was obtained in the case of a solution temperature of 900°C, which showed a tensile strength close to 812±4 MPa and an elongation close to 11.1±2.4 %. The fine αs phase facilitates the paths of crack propagation, meaning decrease the crack propagation resistance and decrease the ductility and fracture toughness.