Effect of process parameters on the mechanical behavior of Ti6Al4V alloys fabricated by laser powder bed fusion method

Abstract

The parameters used in the production process in laser powder bed fusion (L-PBF) technology, one of the additive manufacturing methods, have a critical effect on the mechanical behavior and density properties of the product and can change the properties of the product. Therefore, this study examined the influence of laser power, scanning speed, hatch spacing and beam rotation angle on the tensile strength, impact energy, surface roughness, and porosity levels of Ti–6Al–4V produced through the L-PBF method. It was observed that the tensile strength changes directly proportional to the laser power. In addition, the tensile strength decreases significantly with a value of 645 MPa obtained at lowest 0.07 mm hatch spacing, 190 W laser power and 900 mm scanning speed. The lowest value of impact energy, with a value of 8.7 J, was reached at a rotation angle of 180°. It has been determined that surface roughness decreases significantly with increasing laser power, while it demonstrates an increase with higher scanning speeds. Surface roughness values of 8.9 μm parallel and 8.35 μm perpendicular to the building direction were achieved at a laser power level of 220 W. Laser power was identified as the most influential factor in determining the porosity ratio, with a high porosity rate 0.48% occurring at 160 W laser power. Furthermore, an increase in scanning speed resulted in a corresponding increase in the porosity rate.

Keywords

• Selective laser melting
• Laser powder bed fusion
• Ti–6Al–4V
• Mechanical properties
• Porosity