Electrochemical and passive behaviors of Ti-Fe-B alloy manufactured via casting, forging and additive manufacturing

Additive manufacturing (AM) on titanium has been widely studied due to its freedom on structural designing and personalized manufacturing abilities which fulfill the demands in medical application. However, the microstructure of AM parts present a significant difference from traditional manufacturing methods and leave its biocorrosion resistance performance unclear. Therefore, a comprehensive study of AM parts corrosion behavior is carried out on a newly designed low-cost biomaterial Ti-Fe-B in this study and compared with sample manufactured via casting and forging as well. The results indicate that the AM parts presenting a higher corrosion resistance due to the grains and precipitates size decreased when compared with casting and forging samples, which leads to the corrosion resistance increasing by 24.18% and 6.08% accordingly. The pitting depth of casting, forging and AM parts are 23.52 μm, 15.54 μm and 3 μm respectively. The passive film nucleation and growth mechanism analysis results indicate that a thicker film formed on additive manufactured sample. The grain refinement and pinning action of TiB precipitates attributed to a higher valence oxides, and leading to a superior corrosion resistance of AM parts than that of casting and forging.