Characterisation of Additively Manufactured Metallic Stents

This paper focuses on microstructural characterisation of metallic stents produced with additive manufacturing, a promising technique to deliver patient-specific stents. A 316L stainless steel tube, manufactured by selective laser melting (SLM), and a 316L stainless steel stent were investigated. Specimens were prepared for microstructural studies through sectioning, mounting, grinding and metallurgical polishing procedures. Microstructures were examined employing a JEOL 7100F scanning electron microscope, with simultaneous elemental analysis using energy dispersive x-ray spectroscopy (EDS) and orientation analysis with electron backscatter diffraction. The obtained results showed that a center of the selective laser melted (SLMed) tube had a columnar and coarse grain microstructure, with high-angle grain boundaries. The EDS analysis confirmed that the composition of the SLMed tube were similar to those of commercial stent, but with some differences in weight fractions of alloy elements.