Microstructural examination and corrosion behavior of selective laser melted and conventionally manufactured Ti6Al4V for dental applications

摘要

The selective laser melting of Ti6Al4V would induce definite changes in the microstructure that may affect its corrosion properties. Microstructural examination showed the formation of relatively thin beta (beta) lamella in selective laser melted (SLM) Ti6Al4V compared to wrought Ti6Al4V. X-ray diffraction analysis (XRD) analysis confirmed the presence of alpha and beta phases in both SLM and wrought Ti6Al4V. However, the higher concentration of the beta phase in SLM Ti6Al4V compared to wrought Ti6Al4V was evident in the microstructure. As candidate dental implant materials, the corrosion behavior of both SLM and wrought Ti6Al4V was assessed in artificial saliva (AS) and deionized water (DI) containing various species i.e. fluoride (F), calcium chloride (CaCl2) and lactic acid (LA). Electrochemical impedance spectroscopy and potentiodynamic polarization analysis was carried out to estimate the corrosion behavior of SLM and wrought Ti6Al4V at room temperature. SLM Ti6Al4V offered better corrosion resistance than wrought Ti6Al4V in all solutions at pH > 6. However, wrought Ti6Al4V comparatively presented high corrosion resistance in AS+ LA, DI+ CaCl2 and DI+ LA solutions (pH < 6). The lower dissolution rate of SLM Ti6Al4V (at pH > 6) was attributed to larger beta content in the microstructure compared to wrought Ti6Al4V.