Local composition detouring for defect-free compositionally graded materials in additive manufacturing

Abstract

This study investigated cracking phenomena in 316L stainless steel (SS316L) and Inconel 718 (IN718) composition-graded material (CGM) additively manufactured by the direct energy deposition (DED) process. In order to prevent cracking in the CGM, thermodynamic analysis was performed to avoid the critical concentration for crack formation. Based on the local compositional detouring (LCD) method suggested by new approach, a crack-free CGM with a nonlinear combination of SS316L and IN718 was successfully fabricated with local additional elemental powder in the CGM defective region obtained using a multi-powder feeding system during the DED process.