Developing Fused Deposition Modeling Additive Manufacturing Processing Strategies for Aluminum Alloy 7075: Sample Preparation and Metallographic Characterization

Abstract

Currently, no commercial aluminum 7000 series filaments are available for making aluminum parts using fused deposition modeling (FDM)‐based additive manufacturing (AM). The key technical challenge associated with the FDM of aluminum alloy parts is consolidating the loosely packed alloy powders in the brown‐body, separated by thin layers of surface oxides and polymer binders, into a dense structure. Classical pressing and sintering‐based powder metallurgy (P/M) technologies are employed in this study to assist the development of FDM processing strategies for making strong Al7075 AM parts. Relevant FDM processing strategies, including green-body/brown‐body formation and the sintering processes, are examined. The microstructures of the P/M‐prepared, FDM‐like Al7075 specimens are analyzed and compared with commercially available FDM 17‐4 steel specimens. We explored the polymer removal and sintering strategies to minimize the pores of FDM‐Al7075‐sintered parts. Furthermore, the mechanisms that govern the sintering process are discussed.