The influence of process parameters on corrosion behavior of Ti6Al4V alloy processed by selective laser melting

Abstract

Ti6Al4V alloy exhibits good biocompatibility and has a wide range of applications in the medical fields. Additive manufacturing, especially selective laser melting (SLM), provides a new and effective way for the fabrication of Ti6Al4V alloy biological components. The corrosion resistance of SLM processed Ti6Al4V alloy needs further investigation, which is important for the application of biological components. In this study, Ti6Al4V alloy was fabricated by SLM using different process parameters. Electrochemical measurements including open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy were performed to study the influence of laser scan speed on the corrosion behavior of SLM fabricated Ti6Al4V specimens. The corrosion resistance on different planes of SLM fabricated Ti6Al4V alloy was further characterized. The electrochemical measurements indicated that the corrosion resistance was reduced as the laser scan speed increased. Microstructure analysis suggested that the inferior corrosion resistance under a high laser scan speed was related to the decreased densification behavior. Compared to the XZ-plane, the XY-plane possesses a superior corrosion resistance. The anisotropic corrosion resistance on XY- and XZ-planes of SLM fabricated Ti6Al4V alloys is attributed to the different microstructures on different planes, where more α′ martensite and less β-Ti phase were formed on the XZ-plane than on the XY-plane.