| Abstract Scope |
Additive manufacturing of Ni based superalloys, well known for their application in jet turbines, is being investigated because of its potential, but is somewhat limited currently due to a variety of reasons, including poor sintering, internal porosity, and cracking from residual stresses. A combined particle-based ink extrusion and gas-phase alloying approach could overcome some of the aforementioned issues and be used to produce Ni-based scaffolds, with high surface area and low density. In this work, Ni-Cr structures are 3D printed and subsequently gas-phase alloyed with Al via pack cementation. Upon homogenization, Kirkendall pores form internal to the printed struts and can coalesce into interconnected channels, further lowering the density and increasing the surface area of these scaffolds. Furthermore, a reverse pack cementation step, can be used to tailor Al content, which along with a homogenization and aging treatment, results in the desired gamma/gamma prime microstructure, essential for Ni-based superalloys. |