Experimental investigations into corrosion behaviour of DMLS manufactured Ti6Al4V alloy in different biofluids for orthopedic implants

Abstract

Ti6Al4V alloy is widely used in the biomedical implants industry due to the excellent combination of biocompatibility, mechanical strength &amp

corrosion properties. However, long-time use of Ti6Al4V implants may result in degradation at surge due to corrosive conditions of the human body. In this study, a three-electrode electrochemical cell was used to investigate the corrosion behavior of Ti6Al4V alloy parts manufactured using direct metal laser sintering (DMLS) and conventional cast technique. The corrosion behaviour of Ti6Al4V alloy was investigated in three different biofluids (corrosion media) physiological saline solution (PSS), simulated body fluid (SBF), and phosphate-buffered saline (PBS) using the potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) test. The relevant results showed that the DMLS-produced Ti6Al4V alloy has ∼22 % higher corrosion resistance than the conventionally cast Ti6Al4V alloy in all three biofluids. The microstructural study revealed that it is due to the fine grains and martensitic microstructure of DMLS-produced samples. Additionally, the DMLS-produced Ti6Al4V alloy in SBF has the lowest corrosion rate of 3.44×10−4 mm per year and exhibits the highest polarization resistance of 3364 Ω.cm2 due to the formation of a stable passive film. Apart from corrosion, the surface characteristics of the corroded samples were also studied using hardness and wettability tests. Additionally, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were also performed to understand the reason behind the results obtained. From all these results, it concluded that the corrosion resistance of the cast and DMLS-produced Ti6Al4V alloy in all three biofluids followed the order of PSS &lt

PBS &lt

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