Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti6Al4V Alloy Fabricated by Selective Laser Melting

The additive manufacturing (AM) 3D printing technique is the most feasible, advanced technology for metal parts that have attracted great attention in the manufacturing industry. AM of titanium alloys by selective laser melting (SLM) is one of the most recent research developments in this field because of its benefits and wide applicability in manufacturing sectors. SLM is an efficient, convenient AM technology that can quickly form complex structures. A well-known titanium alloy named Ti6Al4V, manufactured by SLM, has several practical applications in engineering technology, including cars, space shuttles, and aeronautics. This paper demonstrates the density, sectional morphology, microstructure, and mechanical properties before and after heat treatment of Ti6Al4V alloy sample due to laser power, exposure time, and line spacing. A selective laser melting technology was used to fabricate the Ti6Al4V samples. The results show that the sample defects decreased with the increase in laser power. Moreover, when the laser power was 400 W combined with an exposure time of 30 mu s, the sample's tensile strength reached 1203 MPa, almost 300MPa greater than that of ordinary forged Ti6Al4V titanium alloy after annealing. The continuous variation in the line spacing within a certain limit (50-65 mu m) could increase the relative density up to 99.59%, which is much better than previously reported results. The tensile fracture of the sample presents a brittle crack.