Correlation of microstructural with corrosion behaviour of Ti-6Al-4V specimens developed through selective laser melting technique

Abstract

Ti-6Al-4 V (Ti64) alloy is majorly preferred for fabricating the parts in biomedical, aerospace and automobile industries. Traditional manufacturing techniques are mostly involved in making these parts. This work is focused on evaluating the as-cast and Selective Laser Melting (SLM) printed Ti64 specimens in terms of microstructure, hardness and corrosion resistance. The microstructure and the hardness of as-cast and SLM printed samples were examined using FESEM with EDS followed by Vickers microhardness test The corrosion resistance offered by both samples at different durations was investigated in an electrochemical workstation followed by the examination of the corroded surface roughness. The results showed that the existence of martensite microstructure in the SLM printed Ti64 sample has paved the way for enhancing the hardness property compared with the as-cast specimen. Furthermore, the corrosion analysis revealed that the formation of strong and compact passive film has been observed on the SLM samples which resist corrosion. This is due to the even distribution of stabilizing elements followed by martensite phase formation with subsequent solidification during the SLM process. The electrochemical impedance spectroscopy (EIS) analysis and surface roughness evaluation also confirm that the SLM samples have a better passive film with higher R_p and lower R_a values, thereby providing greater resistance against corrosion.