Comparison of Microstructural Response to Heat Treatment of Inconel 718 Prepared by Three Different Metal Additive Manufacturing Processes

Optimization of metallic components fabricated from age hardenable alloys relies on the use of effective heat treatments. As additive manufacturing (AM) is taking its place as “another tool in the toolbox” for fabrication of metallic components, numerous processes are under development differing mainly by the starting feedstock and heat source. In parallel with these efforts is the optimization of the post-processing heat treatment to obtain the required properties. Due to differences in the various processes, it is expected that different microstructures will form in the AM specimens possibly affecting the mechanical behavior. To address optimization of heat treatments requires an understanding of how the starting microstructure responds to heat treatments. This study looks at inherent differences in the response of Inconel 718 to heat treatments developed for wrought 718. Three different AM processes were used to fabricate the samples in this study.