Additive Manufacturing of Three-Phase Syntactic Foams Containing Glass Microballoons and Air Pores
High-density polyethylene and its syntactic foams reinforced with 20 vol.% and 40 vol.% glass microballoons were 3D printed using the fused filament fabrication method and studied for their compressive response. The three-phase microstructure of syntactic foams fabricated in this work also contained about 10 vol.% matrix porosity for obtaining light weight for buoyancy applications. Filaments for 3D printing were developed using a single screw filament extruder and printed on a commercial 3D printer using settings optimized in this work. Three-dimensional printed blanks were machined to obtain specimens that were tested at 10−4 s−1, 10−3 s−1, 10−2 s−1 and 1 s−1 strain rates. The compression results were compared with those of compression-molded (CM) specimens of the same materials. It was observed that the syntactic foam had a three-phase microstructure: matrix, microballoons and air voids. The air voids made the resulting foam lighter than the CM specimen. The moduli of the 3D-printed specimen were higher than those of the CM specimens at all strain rates. Yield strength was observed to be higher for CM samples than 3D-printed ones.
The authors acknowledge William Ricci of Trelleborg Applied Technologies for providing GMBs. The Summer Undergraduate Research Program at NYU-Tandon is thanked for providing a fellowship to Alex Deptula to work on this project. Partial funding from 3DP Security, Inc., is also acknowledged. Mrityunjay Doddamani acknowledges DST Grant DST/TSG/AMT/2015/394/G from the Government of India and thanks the ME Department at NIT-K for providing facilities and support.