Improved Corrosion Resistance on Selective Laser Melting Produced Ti-5Cu Alloy after Heat Treatment

A Ti-5Cu alloy produced by selective laser melting exhibits a nonuniform Ti₂Cu phase structure, which contains a small amount of α' phase in melt pool boundaries thereby resulting in reduced corrosion resistance. The heat-treatment process proposed in this work eliminates the deleterious effect of α' phase and the Ti₂Cu phase is refined using different cooling rates, which improves the corrosion resistance. The electrochemical results indicate that the heat-treated Ti-5Cu samples have similar corrosion behavior to pure CP-Ti. A slower cooling rate produces a larger spacing between the Ti₂Cu phases in the microstructure of the sample, resulting in higher corrosion resistance. The corrosion behavior of SLM-produced Ti-5Cu and heat-treated counterparts with different microstructure are detailed discussed.