Achieving an optimal combination of strength and ductility of a hot-rolled Ti-6121 alloy by tuning solution temperature

Ti-6Al-1Cr-2Mo-1V (Ti-6121) is a recently developed titanium alloy with exceptional mechanical properties, making it a promising candidate for aerospace and armor applications. However, the mechanistic understanding of how solution temperature governs phase evolution and mechanical properties remains limited. In this study, we systematically investigate the effect of solution temperature (800–1000 °C) on the microstructure and tensile properties of hot-rolled Ti-6121 alloy subjected to subsequent aging at 550 °C for 6 h. Microstructural characterization reveals that increasing the solution temperature reduces the volume fraction of primary α (α P ) phase and promotes β → α’ martensitic transformation above 900 °C. Aging thereafter leads to the precipitation of abundant secondary α (α S ) phases. Tensile tests demonstrate that strength increases with solution temperature, while ductility declines. Notably, the alloy solution-treated at 900 °C for 1 h and aged at 550 °C for 6 h achieves an optimal strength–ductility balance, with an ultimate tensile strength of ∼1387 MPa and an elongation of ∼11 %. This superior performance is attributed to the synergistic effects of hierarchically distributed α P phases, nanoscale α S precipitates, and high dislocation density. Our findings provide new insights into the heat treatment-microstructure-property relationships in Ti-6121 alloy, facilitating its development as a high-performance structural material.