Permanent metallic implants are non-degradable therefore remain inside the body which may necessitate secondary surgery for removal. To overcome such problems, biodegradable (BD) metallic implants (Fe-Mn, Mg, Zn, Mo) are being developed [1]. Extensive studies have been carried out on Mg based alloys and are recently being commercialized for dental, trauma and orthopedic applications [2]. In recent years, Fe-Mn based alloys are gaining interest due to its high mechanical strength and excellent biocompatibility properties [3].

A Fe-Mn based alloy has been developed by Vacuum Induction Melting (VIM) subsequently the alloy powders suitable for additive manufacturing (AM) were synthesized by Inert Gas Atomization (IGA). The powders were characterized for phase, chemical composition, microstructure, morphology, particle size and size distribution, tap and apparent densities and flowability. More than 63% yield of Powder Bed Fusion Additive Manufacturing (PBF-AM) grade powder (SLM and EBM) was obtained. The process parameters of Selective Laser Melting (SLM) process were optimized to obtain defect free coupons. The AM coupons were characterized for phase, mechanical, magnetic properties, roughness, degradation rate (Electrochemical and Immersion) and biocompatibility. The developed alloy is found to be non-cytotoxic [ISO 10993-5].

As-built AM coupons exhibited lower susceptibility (2.2 x10-7 m3kg-1) which is lower than the 316 L stainless steel. A very high degradation rate (EC) of 0.1 mm/year was obtained for AM made coupons which is more than 5 times higher compared to as-cast sample. The AM built samples exhibited very good mechanical properties such as elongation of 24±3%, UTS of 642±10 MPa were obtained . A soft tissue anchor was designed and successfully printed by SLM. The AM coupons were electro- polished to remove unwanted residue and roughness on the sample. In addition hydroxyapatite was deposited on the surface for better osseointegration. In this presentation, the influence of different process parameters on degradation rate, mechanical properties, biocompatibility, physical and antibacterial properties of Fe-Mn BD alloys for implant will be discussed.

References

 1. Y.F.Zheng ,X.N. Gu and F. Witte, Biodegradable metals, Mat. Sc and Engg. R, 2014, vol. 77, pp1-34.

 2. V. Tsakiris et al., J. Magnes. and Alloys, 2021, vol. 9, pp.1884-1905

 3. R. Gorejova et al., J Mater Sc, 2018, vol. 54, pp. 1913-1947