Role of Stable Keyhole Mode in the Formability, Microstructure, and Mechanical Properties of High Layer Thickness in Laser Powder Bed Fusion of Ti-6Al-4V Alloy

In this study, we printed high layer thickness Ti-6Al-4V parts using a stable keyhole melt pool mode. Firstly, we performed the single tracks experiments to obtain the size of the melt pool at different scanning speeds. Results demonstrated that the depths of the molten pools are high which makes it possible to improve the building rate by increasing layer thickness. Under the conditions of 170 W laser power, 60 μm layer thickness, and a scanning speed of 900 mm/s, the building rate, relative density, microhardness, ultimate tensile strength (UTS), yield strength (YS), and elongations are 424 HV, 3.78 mm3/s, 99.4