Additively manufacturing of functionally graded multi-material parts using directed energy deposition

Manufacturing of functionally graded (FG) components is desirable for many applications because of the capability of providing multiple functionalities and higher performance on the same component. Complex multi-material components cannot be produced using conventional manufacturing processes; therefore, additive manufacturing (AM) processes have recently been used for manufacturing multi-material parts. The laser powder directed energy deposition (LP-DED) process is a metal-based AM technique with multi-material production capabilities; however, the link between a complex multi-material design and the LP-DED machine is still missing. This paper aims to develop a unified algorithm to carry out design, process planning and manufacturing of complex multi-material parts, and generate the computer numerical control (CNC) program. The proposed methodology is implemented to produce functionally-graded multi-material samples using two different materials and functionalities namely, CuCrZr and Inconel 718 to demonstrate its capabilities. The energy dispersive spectrometry (EDS) and microhardness analyses are carried out on one of the case studies to evaluate the precision of material composition throughout the gradient direction. Overall, the developed algorithms are well-integrated with LP-DED systems and proved to be capable of producing spatially and materially complex FG structures directly from designs.