Effect of heat treatment on the corrosion resistance behavior of selective laser melted Ti6Al4V ELI

Ti6Al4V ELI bone substitutions fabricated by selective laser melting (SLM) have shown potentials in future implants market. Corrosion resistance is an important property to SLM Ti6Al4V materials for biomedical applications. However, to date, very few studies focused on the corrosion properties of SLM Ti6Al4V materials. This paper reported a comprehensive investigation on the effect of heat treatment including vacuum annealing and hot isostatic pressing (HIP) on the corrosion properties of SLM Ti6Al4V ELI samples. The results demonstrated that vacuum annealing could modify the microstructure of the as-fabricated SLM Ti6Al4V sample by transforming a phase into beta phase. As a consequence, the corrosion resistance performance was improved due to the increased beta phase. For HIP treatment, in addition to the increased beta phase, the applied high pressure also reduced the porosity to nearly zero, which further improved the corrosion resistance performance of the SLM Ti6Al4V sample.