Process Optimization and Characterization of Inconel 718 Manufactured by Metal Binder Jetting

The development of a process chain for Inconel 718 production utilizing Binder Jetting has been investigated. Different powder sources were compared by the effect they had on machine compatibility, powder bed packing, recyclability, green density, sintering parameters, final density, porosity, and mechanical properties. The three powder lots investigated originated from two different production sites. One of the three powder lots has a finer powder size distribution, due it being produced simultaneously with another powder lot with a coarser powder size distribution fraction. This synergy production results in a higher yield of the atomization process and thus is economically and environmentally beneficial. The compatibility between powder lots and Binder Jetting machine was investigated using new powder and recycled powder. By using recycled powder in the process an increase in green density by 5% could be achieved. Several temperature and hold time relations were tested to develop a sintering program with an acceptable final density above 94% of theoretical density. 1270◦C with a hold time of 4h generated the best results. Sintered samples did not reach acceptable strength properties. The elongation value was twice as high as required for one of the powder lots using recycled powder. Post heat treatment generated samples with an acceptable yield strength but highly reduced elongation properties