Grain morphologies in additively manufactured alloys: from solidification fundamentals to advanced microstructure control

Abstract

In comparison to the alloys manufactured using the conventional means, microstructures of the alloys additively manufactured (AM) using techniques such as laser powder bed fusion (LPBF), directed energy deposition (DED) and e-beam powder bed fusion (EPBF) are considerably more complex, making them unamenable for an easy interpretation even for a well-trained metallurgist. Keeping this in view, an overview of different grain morphologies that are observed in AM alloys is presented, with the objective of a systematic elucidation of the melt pool geometry and thermal history's role on the microstructural evolution. The second part of this review focuses on strategies that are available for manipulating the grain structures for tailoring the microstructures of AM alloys.