Impact of Gamma Radiation on the Thermal and Mechanical Properties of Additively Manufactured PA12 Composites

Data for the Paper "Impact of Gamma Radiation on the Thermal and Mechanical Properties of Additively Manufactured PA12 Composites"

PA12 composites (containing carbon or glass microfibers) were printed by fused deposition modeling (FDM) and selective laser sintering (SLS) and exposed up to 20 MRad (Co-60 gamma irradiation). Specimens were analyzed by modulated differential scanning calorimetry (MDSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) to understand radiation-induced chemical changes. Mechanical properties were assessed through tensile testing and post irradiation scanning electron microscopy (SEM) fractography. The FDM melting process delivered more thermodynamically stable parts with improved polymer-polymer contact. DSC thermal cycling did not seem to heal AM products that suffered minor radiation damage at the highest exposures. The TGA data reveal high gamma irradiation lowers early stage decomposition temperatures (by 27 to 34 °C) of all composites regardless of print method. Neat PA12 SLS had a higher ultimate tensile strength and significantly smaller cross-head displacement at failure compared to FDM. In contrast, FDM prints were twice as strong as SLS, retaining strength up to 20 MRad. While carbon and glass fillers increased strength of PA12 FDM composites, this came with increased variation in measured data and fiber pullout by 20 MRad. Together, the data suggest FDM is better than SLS for printing strong, resilient PA12 materials, whose structural integrity can be further enhanced with small (<10 wt%) microfiber filler.