Ti6Al4V, a grade 5 titanium alloy, is widely utilized in aerospace, biomedical, marine, and energy sectors due to its high strength-to-weight ratio, superior corrosion resistance, and excellent biocompatibility. With the advent of advanced manufacturing techniques such as Additive Manufacturing (AM), the production of intricate geometries has become more efficient compared to traditional methods. However, the localized thermal gradients generated during AM processes significantly influence the microstructure, pore morphology, and mechanical properties of the material. This study investigates the effects of heat treatment on the microstructure, pore morphology, and micromechanical properties of AM-produced Ti6Al4V specimens.
Using Micro-Computed Tomography (Micro CT) and X-ray Diffraction (XRD), pore defect volumes, distributions, equivalent spherical diameters, and sphericity coefficients were analysed under three heat treatment conditions (550°C, 750°C, and 1150°C). The average pore volumes were found to be 1.975 × 10⁻⁴ mm³, 1.2838 × 10⁻⁴ mm³, and 4.347 × 10⁻⁵ mm³ for the as-cast and heat-treated samples at 550°C, 750°C, respectively. The mean sphericity values were 0.747, 0.749, and 0.921, indicating improved pore uniformity and shape at 750°C.
Hardness measurements revealed values up to 7.17 GPa, while the reduced modulus values up to 139.57 GPa. The results demonstrate that annealing at 750°C achieved the most favourable balance between reduced pore volume and uniformity, attributed to stabilization of the alpha phase and atomic diffusion minimizing surface energy. Additionally, at this temperature, the mechanical properties were improved, providing a balance between strength and elasticity. These findings highlight the potential of heat treatment optimization to enhance the performance of AM- produced Ti6Al4V for demanding applications.