COMPARISON OF POWDER-BED FUSION, DIRECTED-ENERGY DEPOSITION AND HYBRID ADDITIVE MANUFACTURING OF Ti6Al4V COMPONENTS: MICROSTRUCTURE, CORROSION AND MECHANICAL PROPERTIES

This study investigates the microstructure, corrosion resistance, and mechanical properties of Ti6Al4V components fabricated using powder-bed fusion (PBF), directed-energy deposition (DED), and hybrid additive manufacturing (HAM) for aerospace applications. To prevent ’ martensite formation, the samples were subjected to heat treatment. The microstructure was characterized using optical microscopy (OM), scanning electron microscopy (SEM), and electron-backscatter diffraction (EBSD). Corrosion resistance was assessed through potentiodynamic polarization tests, and mechanical properties were evaluated using Vickers hardness measurements. The PBF sample exhibited a fine, homogeneous microstructure with crystal grains and α-laths, while the DED sample showed visible deposition layers, a larger crystal grain structure, and α-lamella. The increased hardness of the DED sample was attributed to its higher nitrogen content, which acts as a solid-solution strengthening agent. Although the DED sample displayed lower thermodynamic stability, it demonstrated superior kinetic corrosion resistance compared to both the PBF and HAM samples.