Development of in-plane SS316 to M300 maraging steel gradients via directed energy deposition

Abstract

• Creation of in-plane multi-material and gradient samples via powder directed energy deposition • Gradient deposition strategy resulted in less build-direction interfacial tortuosity • Gradient deposition strategy created discrete in-plane hardness and composition transitions • Blank scans resulted in broader alloy transition regions and additional interfacial tortuosity The development of functionally gradient materials via powder-based directed energy deposition is of interest to fabricate metallic aerospace components with tailored spatial properties. Currently, multi-metal and functionally graded metallic samples are fabricated with the transition or gradient in the build direction due to equipment hardware and software limitations. To enable full spatial control of component composition and properties, the development of a process for creating in-plane gradients and an understanding of the influence of process parameters on interfacial properties is necessary. This work highlights the manufacturing of in-plane gradients through powder-based directed energy deposition for SS316 and M300 maraging steels. An exploration of the influence of process parameters is performed, including the correlation of material deposition spacing, interfacial gradient strategy, and re-melting blank laser scans, with sample hardness, composition, and interface morphology. Finally, the in-plane gradient strategy is utilized to create a prototype geometry with a low- coefficient of thermal expansion.