Selective laser melted Fe-Mn bone scaffold: microstructure, corrosion behavior and cell response

Iron metal possesses good biocompatibility and excellent mechanical strength, though it degrades too slowly. In this work, selective laser melting (SLM) was applied to fabricate iron-manganese (Fe-Mn) biodegradable scaffold. Results shown Fe-Mn scaffold exhibited a uniform pore structure with a porosity of 66.72±2.3%, which highly matched with as-designed model. Phase analysis revealed Fe-Mn scaffold mainly contained α-Fe, martensitic and austenitic phases. Due to the potential difference among these different phases, galvanic corrosion occurred in Fe matrix. In addition, a small amount of Mn distributed at grain boundaries also contributed to the formation of galvanic corrosion. Thus, the corrosion rate increased from 0.09±0.02 mm/year to 0.23±0.05 mm/year. The scaffold exhibited suitable mechanical properties with a yield strength of 137±8.4 MPa, an ultimate strength of 221.7±10.9 MPa. Moreover, cell assays demonstrated its good cytocompatibility. Taking these positive results into consideration, SLM processed Fe-Mn scaffold was a promising material for bone repair application.