Influence of build orientation, heat treatment, and machining on the mechanical properties of PBF-LB/M Ti6Al4V

Abstract This study investigates the mechanical behavior of Ti6Al4V components produced via laser-based powder bed fusion of metals (PBF-LB/M), with a focus on the effects of build orientation, heat treatment, and machining. Destructive testing methods—including tensile, Charpy impact, bending, and Poisson’s ratio measurements—were employed to evaluate mechanical properties under various conditions. Stress-relief heat treatment reduced residual stresses and resulted in a moderate decrease in strength. Compared to non-heat-treated specimens, the 0.2% offset yield strength decreased by approximately 20–100 MPa (≈ 2–9%), while ultimate tensile strength showed a similar reduction, remaining in the range of about 1100–1250 MPa. Machining had no significant influence on yield or tensile strength, with differences below 100 MPa, less than 8–9% of the measured strength values. Build orientation showed minimal effect on tensile properties, with all values are within an approximately 150 MPa range, which represents about 12–14% variation across orientations. Poisson’s ratio ranged from 0.29 to 0.33. Heat treatment and machining the V-notch also increased Charpy impact energy. Bending strength was slightly higher for XZ and XY orientations (≈ 2300–2600 MPa) than for Z-oriented specimens, while counter-deformation reduced bending strength by less than 5%. Additional post-processing techniques such as glass blasting and counter-deformation had limited impact. These findings highlight how strategic process optimization can improve the performance and efficiency of PBF-LB/M manufactured Ti6Al4V parts, making them suitable for demanding industrial applications.