Effect of high energy ball milling on the properties of biodegradable nanostructured Fe-35 wt.%Mn alloy

In this study, nanostructured biodegradable Fe-35 wt.%Mn alloy prepared by 10 h high energy ball milling followed by conventional cold press and sintering. Structural and microstructural properties were studied by X-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy. Corrosion rate, mechanical properties, biocompatibility and cell adhesion of this alloy were evaluated by SaOS-2 cell line and compared with the unmilled sample. Transmission electron microscopy proved the formation of the nanostructured alloy after sintering. The milled sample had the highest micro-hardness of 98 HV, while compression strength of the unmilled sample was higher. The ultimate compressive strength and strain of the unmilled sample were 153.4 MPa and 34%, respectively. Degradation by 60 days decreased both ultimate compressive strength and strain to 138 MPa and 31.5%, respectively. Lower corrosion rate observed for the milled sample was 1.36 mm/yr. On the other hand, the milled sample enhanced cell adhesion and cell viability evaluated by MTT assay.