Supersaturated Solid Solution of Mg in Fe Produced by Mechanical Alloying Followed by Selective Laser Melting (SLM) to Accelerate Degradation for Biomedical Applications
C-J. Shuai, S. Li, C-D. Gao, Y-W. Yang, Z-Y. Zhao, W. Liu and Y-B. Hu
Solid solution of Mg in Fe is an effective strategy to accelerate degradation for artificial bone applications while it is extremely difficult to realize since the melting point of Fe greatly exceeds the boiling point of Mg. Herein we present a supersaturated solid solution of Mg in Fe which was achieved by mechanical alloying and then consolidated by selective laser melting (SLM). First, solid solution of Mg in Fe was accomplished by mechanical alloying in the condition of elements inter-dispersion at low temperature. Then the alloyed powders were rapidly consolidated by SLM to avoid the segregation and evaporation of Mg in the case of extremely short melting and cooling time. X-ray diffraction (XRD) results for the Fe-Mg powders showed that Mg peaks disappeared while Fe peaks broadened and shifted to a low angle after milling for 40 hours, indicating the successful solution of Mg in Fe; consequently, the Fe-Mg alloy presented a much lower potential of -0.805 V than that of alloy at -0.542 V without milling, which increased degradation rate by 2.74 times after immersion for 21 days. MG-63 cells proliferated more rapidly, indicating good cytocompatibility, which showed potentials for artificial bone applications.
Keywords: CO2 laser, Fe-Mg alloy, MG-63 cells, powder, mechanical alloying, selective laser melting (SLM), biodegradation