Process parameter selection for selective laser melting of Ti6Al4V based on temperature distribution simulation and experimental sintering

Considering that the densification level and the attendant quality of selective laser melted Ti6Al4V parts depend strongly on the operating temperature of the melting system, which is mainly controlled by the processing parameters. The processing parameters of selective laser melting were thus investigated in this study to fabricate denser Ti6Al4V parts without post-processes. Temperature distribution calculation was firstly carried out based on a three-dimensional model. It was found that there exists a great temperature gradient from the surface of powder bed to the experimental platform, and the maximum depth of molten powder layer is about 45 mu m, very close to the total thickness of powder bed (50 mu m) under the condition of laser power of 110 W and scan rate of 0.2 m/s. The Ti6Al4V parts with lower porosity and higher density were then well fabricated by experimental method under the condition of laser power of 110 W and scan rate of 0.2 m/s. The experimental results also indicate that the microstructures exhibit more and more pores and the layer structures are more and more obvious with the increase in the scan rate. Moreover, the microhardness measurement yields different values with increasing scan rate, owing to the increase of alpha phase and porosity.