Currently, additive manufacturing, e.g., selective laser melting (SLM), of biodegradable metals and alloys for implant applications is drawing increasing attention. [1-5] This new class of materials is of highest interest as it enables progressive implant degradation after providing temporary support on the healing processes of the diseased tissue. So, revision surgery, chronic inflammation, or lacking adaptation to growth (regarding diseases at infancy) can be avoided. [6-8] Among the biodegradable alloys, Fe-based systems, especially those on FeMn base, are very promising, e.g., for cardiovascular applications due to their excellent processability, a broad range of tunable mechanical properties, their high integrity during degradation, as well as degradation reactions without hydrogen gas evolution in physiological media. This was reported for a variety of alloy systems prepared by different casting and forming technologies. [7-16] Especially, FeMnC-base alloys are promising candidates due to their higher strength and improved cell compatibility compared with many FeMn systems. [11-15] This work is based on a novel developed FeMnCS alloy, which already shows an attractive combination of mechanical properties under tensile load, corrosion rate, and cell compatibility in the as-cast state, as shown in previous studies. [11,14] However, there are still challenges regarding a more homogenous degradation for good temporary structural integrity, an adequate corrosion rate, as well as improved mechanical properties which are comparable or better than those of clinically applied 316L benchmark steel. Until now, there are only a few published studies on the processing of biodegradable Mg-, Zn-, or Fe-based alloys by means of SLM. [1-4,17-20] However, the layer-by-layer technique offers a flexible production of parts with a high degree of individualization or complex geometries and a high level of function integration, which can often not be generated by conventional manufacturing techniques. [21,22] Furthermore, SLM is a rapid solidification technique, which yields particular microstructural phenomena like grain refinement, extended solid solubility and reduction of quantity, and size of phase segregations. These effects can be very beneficial for the properties of metallic biomaterials as it was already demonstrated by different authors for various nondegradable materials like 316L, Ti-based, or CoCr-based alloys, also partially considering the influence of the SLM building orientation. [21-29] Consequently, the exploitation of advantages of SLM for the production of patient-specific degradable implants with tailored microstructures appears to be a promising approach.
