Ti-5553 (Ti-5Al-5Mo-5V-3Cr), a newly developed β-Ti alloy, is a potential alternative for aircraft structural applications. Recent publications confirm the printability of this alloy through laser powder bed fusion but with substandard tensile strength. The inferior tensile properties reported could be a result of rapid heating and solidification rates involved in the metal additive manufacturing processes, which often results in an unfavorable microstructure and accumulated residual stresses, hence resulting in poor mechanical properties. Also, heat cycles involved in the layer by layer material deposition introduce metallurgical heterogeneity along the building direction by default in the printed parts. Thus, post heat treatments are essential to achieve the expected performance in these printed parts.

In this work, the printed Ti-5553 samples were subjected to engineered heat treatment protocols to promote the growth of lamellar α particles. Microstructural characterization on the solution treated and aged samples revealed the growth and uniform distribution of needle-like α phase across the samples. X-Ray diffraction patterns confirmed the presence of α phase in the samples. On comparison, the heat treated samples exhibited higher hardness values, together with a 25% increase in tensile strength at the expense of ductility. The fractured surfaces exhibited localized traces of both ductile and brittle modes of failure, where the dominant mode was brittle fracture.