Abstract
<jats:p>Introduction. Ti-6Al-4V is one of the most commonly used α+β titanium alloys in various industries due to its excellent specific strength and corrosion resistance. Additive manufacturing (AM) processes enable the production of Ti-6Al-4V parts with complex geometries. However, defects and microstructural inhomogeneity in the fabricated parts can adversely affect their mechanical properties. Purpose of the work. The purpose of this study is to investigate the microstructure and mechanical properties of Ti-6Al-4V parts. The defect density and inhomogeneity in the microstructure and mechanical properties of parts fabricated by selective laser melting (SLM), electron beam melting (EBM), and spark plasma sintering (SPS) were examined. The inhomogeneity in mechanical properties, specifically hardness, was quantified. Furthermore, the effects of a laser remelting strategy on microstructural homogeneity were studied. Research methods. Ti-6Al-4V parts were fabricated using additive manufacturing processes, namely SLM and EBM. Parts were also produced via the SPS method. A laser remelting strategy (scanning each layer three times) was applied during the SLM process. The effects of laser remelting on defects, microstructure, and mechanical properties were studied and compared with standard SLM (scanning each layer once), EBM, and SPS. Results and discussion. A lamellar α/α′ microstructure was observed in the SLM samples, both in the as-built and remelted conditions (denoted as SLM and SLM-RM, respectively). The hardness of the SLM sample (335 HV) was found to be higher than that of the SPS sample (305 HV). Application of the remelting strategy in SLM led to an increase in hardness and improved its homogeneity. The average size and shape irregularity of porosities in the SLM samples were analyzed; it was observed that surface porosity decreased with the implementation of the remelting strategy. Laser remelting significantly influences the performance of the SLM process. The results demonstrate that these synthesis processes yield Ti-6Al-4V alloys with distinct microstructural and mechanical properties.</jats:p>