Structural characterization and biocorrosion behaviour of direct metal laser sintered Ti6Al4V–ZrO2 tracks: Influence of processing parameters

Abstract

Titanium (Ti–6Al–4V) and Zirconia (ZrO2) have proven to be candidate materials for use in the biomedical industry. This present study investigates the effect of processing parameters on microstructural and corrosion performance of Ti–6Al–4V– ZrO2 laser tracks processed via direct metal laser sintering technique. The starting powders were mixed using a turbula mixer. The morphology of the admixed Ti–6Al–4V– ZrO2 powders and the laser melt tracks were examined under a field emission electron microscope (FE-SEM) equipped with energy dispersive X-ray (EDS). X-ray diffraction (XRD) analysis was carried out on the starting powders and laser tracks to ascertain the phases formed before mixing and after laser sintering, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy technique (EIS) were used to investigate the resistance of the laser tracks to corrosion in Hanks simulated body fluid. The FE-SEM examination showed a homogeneous mixture of the powders, while the laser melt tracks processed at lower scanning power revealed the presence of discontinuities. The corrosion analysis of the laser tracks in Hanks solution showed synergy between the results obtained from the potentiodynamic polarization and EIS analysis. This research established that the specimen fabricated using a laser power of 340 W, a scanning speed of 1 m/s, and a layer height of 100 μm exhibited the most improved corrosion resistance in the test environment used in this study.

Keywords

• Additive manufacturing
• Direct laser melting technique
• Ti–6Al–4V
• Zirconia
• Laser melt track
• Electrochemical impedance spectroscopy