The Effects of Laser Powder Bed Fusion Process Parameters on Material Hardness and Density for Nickel Alloy 625
Christopher U. Brown, Gregor Jacob, Antonio M. Possolo, Carlos R. Beauchamp, Max A. Peltz, Mark R. Stoudt, M A. Donmez
The goal of this study was to investigate the relationship between mechanical and material properties (including density) of manufactured nickel super alloy (IN625) using a laser powder bed fusion process and three process parameters: laser power, hatch distance, and scan speed. Hardness of the manufactured blocks was measured as a representative of the mechanical properties. Density measurements were carried out using the pyncometry method. Three sets of blocks were manufactured using IN625 metal powder (nitrogen gas atomized) on a laser powder bed fusion machine (EOS M270). Different combinations of process parameters yielded different energy densities for each block for the three builds. The laser scan speed, laser power, hatch distance, and energy density all had statistically significant relationships with hardness. The average bulk density increased non-linearly with increasing values of energy density. A similar trend was in the hardness data. The results of this study served as a guide to determine the range of parameters yielding acceptable material properties for the investigation of process parameter sensitivities during a subsequent IN625 round robin study.