Application-driven optimization of Ti-6Al-4V alloy via customized heat treatments

Abstract

This paper examines the influence of controlled heat treatments on the mechanical behaviour of Ti-6Al-4V (Grade 5 Titanium alloy) to improve its performance in structural and high performance applications. Ti-6Al-4V is widely used in aerospace, biomedical and automotive components because of its high strength-to-weight ratio and corrosion resistance: however, simultaneously optimizing strength, ductility, fracture toughness and fatigue resistance remains challenging. Because the alloy is highly sensitive to thermo-mechanical history, heat treatment provides an effective means of tailoring its mechanical response. Four microstructural conditions were examined: (i) annealed, A, (ii) solution-treated and aged, STA, (iii) β-annealed, BA, and (iv) β-solution-treated and overaged, BSTOA. Optical and scanning electron microscopy were used to characterize the resulting microstructures and tensile, hardness, impact strength, fracture mechanics and fatigue tests to determine the respective mechanical properties. A condition exhibited the highest ductility, whereas the STA treatment produced the greatest strength and hardness; BA condition improved fracture toughness, while BSTOA treatment provided the highest high cycle fatigue limit. These findings demonstrated that appropriate selection of the thermal treatment process can significantly enhance the mechanical performance of Grade 5 Titanium alloy for advanced engineering applications.