Role of processing parameters on relative density, microstructure and mechanical properties of selective laser melted titanium alloy

The relationships between the selective laser melting (SLM) processing parameters including laser power, scanning speed and hatch space, the relative density, the microstructure, and resulting mechanical properties of Ti-6Al-2Zr-1Mo-1V alloy were investigated in this work. The result shows that laser power acts a dominant role in determining the relative density in comparison with scanning speed and hatch space. The optimal SLM process window for fabricating relative density >99% samples is located in the energy density range of 34.72 J·mm−3 to 52.08 J·mm−3, where the laser power range is between 125 W and 175 W. An upward trend is found in the micro-hardness as the energy density is increased. The optimum SLM processing parameters of Ti-6Al-2Zr-1Mo-1V alloy are: laser power of 150 W, scanning speed of 1,600 mm·s−1, hatch space of 0.08 mm, and layer thickness of 0.03 mm. The highest ultimate tensile strength, yield strength, and ductility under the optimum processing parameter are achieved, which are 1,205 MPa, 1,099 MPa, and 8%, respectively. The results of this study can be used to guide SLM production Ti-6Al-2Zr-1Mo-1V alloy parts.