Comparison of direct energy deposition and powder bed fusion technology in the preparation of Ti–6Al–4V alloy

The Ti–6Al–4V alloy is the most widely used titanium-based alloy in aerospace and biomedical applications. Due to the complex shapes required for components in these application areas, additive manufacturing has become a promising option with its advantageous speed and precision. This study examined the impact of direct energy deposition (DED) and powder bed fusion (PBF) technologies on the resulting properties of the Ti–6Al–4V alloy. DED-produced samples showed almost fully dense structure, while PBF-produced ones were characterized by 0.3 % residual porosity. In all states, the α or α′ phase predominated in the material microstructure. The Ti–6Al–4V alloy produced by different additive manufacturing methods showed comparable hardness values in both, as-printed (380 HV) and as-printed + heat-treated (370 HV) states. However, the samples printed by the PBF method exhibited higher tensile strength and yield strength than those printed by the DED method. These values before and after stress-relief heat treatment differed by approximately 100 MPa. Conversely, the DED-printed material is more stable at elevated temperatures (up to 800 °C) compared to the one printed by PBF.