Enhancing the degradation rate and biomineralization nature of antiferromagnetic Fe-20Mn alloy by groove pressing.

The Fe-Mn alloys are potential candidates for biodegradable implant applications. However, the very low degradation rates of Fe-Mn alloys in the physiological environment are a major disadvantage. In this study, the degradation rate of a Fe-20Mn alloy was improved using the groove pressing (GP) technique. Hot rolled sheets of 2 mm thickness were subjected to GP operation at 1000°C. Uniform fine-grained (UFG) Fe-Mn alloys were obtained using the GP technique. The influence of GP on the microstructure, mechanical properties, degradation behavior in simulated body fluid (SBF), surface wettability, biomineralization, and cytocompatibility was investigated and compared to the annealed (A Fe-Mn) and rolled (R Fe-Mn) sample. The groove-pressed Fe-Mn (G Fe-Mn) alloy had a grain size of approximately 40 ± 16 μm whereas the A Fe-Mn and R Fe-Mn samples had grain sizes of 303 ± 81 and 117 ± 14.5 μm, respectively. Enhanced strength and elongation were also observed with the G Fe-Mn sample. The potentiodynamic polarization test showed the highest I, lowest polarization resistance, and lowest E for the G Fe-Mn sample among all other samples indicating its higher degradation rate. The weight loss data from immersion tests also shows that the percentage of weight loss increases with time indicating the accelerated degradation behavior of the sample. The static immersion test showed an enhancement in weight loss of 0.46 ± 0.02% and 1.02 ± 0.05% for R Fe-Mn and G Fe-Mn samples, respectively, than A Fe-Mn sample (0.31 ± 0.03%) after 56 days in immersion in SBF. The greater biomineralization tendency in UFG materials is confirmed by the G Fe-Mn sample's stronger hydroxyapatite deposition. When compared to the A Fe-Mn and R Fe-Mn samples, the G Fe-Mn sample has a better wettability, which promotes higher cell adhesion and vitality, showing higher biocompatibility. This study demonstrates that Fe-20Mn processed by GP has potential applications for the manufacture of biodegradable metallic implants.