Optimizing strength and corrosion resistance of the metastable β-alloy Ti–35Nb–7Zr–5Ta alloy by equal-channel angular pressing

Controlling the microstructure of the Ti–35Nb–7Zr–5Ta alloy is fundamental for enhancing its strength and corrosion resistance in biomedical applications. This study examines how microstructural evolution through equal-channel angular pressing (ECAP) at room temperature and 300 °C influences Young's modulus, hardness, and corrosion resistance. ECAP refines grain size and promotes nanocrystalline β-phase grains, α phase decomposition, and ω phase precipitation. Room temperature ECAP decreases Young's modulus by reducing the β-phase stability due to deformation, while 300 °C processing enhances hardness and Young's modulus due to finer microstructure and higher ω-phase fraction. Grain refinement accelerates passivation kinetics, enhancing corrosion resistance with a thicker and less defective passive film, especially at 300 °C, without significant changes in the elemental composition of the outer passive film.