Abstract: A dual-scale lamellar α-phase microstructure was developed in Ti575 alloy through solution treatment in the (α+β) region. Lowering solution temperature coarsened the lamellar α phase and reduced Al content, thereby shifting the early deformation mechanism to α twinning, followed by extensive dislocation slip. The significant twinning-induced plasticity effect from micron-scale α lamellae, combined with the crack-arresting capability of the dual-scale lamellar architecture, increased the elongation from 5.6% to 16.9% while maintaining the alloy’s strength. This approach, which does not require changes to the alloy composition, provides a practical and effective method to significantly enhance the plasticity of titanium alloys without compromising their strength.

Key words: Ti575 alloy, Solution treatment, Al content, Deformation mechanism, Mechanical properties