Mechanical, physical, and degradation properties of 3D printed PLA + Mg composites

Abstract

In the present study, composite filaments were produced by PLA with and without 1 wt% Mg particles. DSC results show that the presence of Mg reduces the crystallinity and increases the melting temperature. Extruded filaments were used to produce tensile samples by 3D printing. The mechanical properties of 3D printed samples were compared with monolithic and micro-sized samples. The monolithic samples show inferior strength and ductility compared to 3D-printed samples, which feature aligned polymer chains. The micro-sized samples show superior mechanical properties compared to the large samples by having fewer potential failure points. 3D-printed samples were also produced by various infill orientations (0o, 45o, ±45o, and 90o), and the samples were tested for biodegradation in SBF solution. The 0o, infill orientation presented the highest mechanical properties before and after the immersion test. The 90o infill orientation samples were the most damaged samples by degradation. Microstructure studies show crevice corrosion is responsible for severe damage to the 90o infill orientation samples. Mg in the crevice forms and locks a local alkaline environment, accelerating degradation.