Microstructure and Mechanical Characterization of Laser Sintered Inconel-625 Superalloy

Direct metal laser sintering (DMLS) is an additive manufacturing technology that uses a high power laser to produce three dimensional parts by sintering metal powders spread on the substrate under protective inert gas environment. This paper focuses on direct metal laser sintering of Inconel-625 super alloy and its characterization. Inconel-625 material was sintered on steel substrate by varying the laser scan speed from 2.5 to 10 mm/s in steps of 2.5, hatch spacing from 0.2 to 0.4 mm in steps of 0.1, while laser power, hatch width and layer thickness were maintained constant at 240 W, 5 mm, 50 μm respectively with laser beam diameter of 0.4 mm. The build orientation during sintering was such that the axis of the cylindrical specimens was parallel to the build direction. Nitrogen atmosphere was maintained in the build chamber. The studies clearly reveal that with increase in laser scan speed and hatch spacing there was an increase in microhardness of the sintered parts while there was a decrease in dimensional accuracy, and density.