Corrosion Behavior and Bio-Functions of the Ultrafine-Grained Ti6Al4V-5Cu Alloy with a Dual-Phase Honeycomb Shell Structure in Simulated Body Fluid

Abstract

Titanium alloys are widely used in biomedical applications. However, cases of implant failure due to fatigue fracture and bacterial infection are common. In addition, implants are susceptible to metal ions (Al, V) released by long-term exposure to human body fluids, which causes neuropathy, mental disorders, and other diseases. Thus, development of novel materials to achieve longterm safety of implants is currently a research hotspot. Recently, our research group has developed an ultrafine-grained Ti6Al4V-5Cu alloy with a unique "dual-phase honeycomb shell" (DPHS) structure, which possesses high fatigue strength and stability. This study further affirmed its higher corrosion behavior, antibacterial properties, and cytocompatibility compared to the coarse-grained Ti6Al4V and Ti6Al4V-5Cu alloys. The ultrafine-grained structure of Ti6Al4V-5Cu having DPHS increased the proportion of phases (Cu-rich phases, β-phase, and Ti 2 Cu intermetallic phase) with a lower surface potential. It was observed that the developed microstructure was conducive to a stable configuration of the oxide (passive) layer on the alloy surface. In addition, the low-phase interfacial energies of the ultrafine-grained structure with DPHS even facilitated the improvement of the denseness of the protective passive film and eventually enhanced the corrosion behavior. Besides, the fine-Cu-rich phases and the micro-galvanic couples formed between them and the matrix significantly increased the contact frequency of bacteria, thus increasing the contact sterilization efficiency of the ultrafine-grained Ti6Al4V-5Cu alloy. These results showed that the new ultrafine-grained Ti6Al4V-5Cu alloy has excellent corrosion resistance and biological functions for clinical application.

Overview of strategies to improve the antibacterial property of dental implants

“…This study suggests that we can control the initial location of attachment of adherent cells by the particular geometry of the features ( Vadillo-Rodríguez et al, 2018 ). Many topographic features have been shown to have an inhibitory effect on the formation of biofilms, such as honeycombs ( Vasudevan et al, 2014 ; Yang et al, 2015 ; Gu et al, 2016 ; Liao et al, 2021 ; Li S. et al, 2023 ), irregular micro pits ( Jeong et al, 2017 ), line patterns ( Lee and Pascall, 2018 ; Wu et al, 2020 ; Damiati et al, 2022 ; Sorzabal-Bellido et al, 2022 ), ridges ( Zhang B. et al, 2014 ; Perera-Costa et al, 2014 ; Lu et al, 2016 ), cylindrical wells ( Fontelo et al, 2020 ; Xiao et al, 2020 ), square pillars ( Hou et al, 2011 ; Halder et al, 2014 ; Ge et al, 2015 ; Valle et al, 2015 ; Ge et al, 2019 ), hexagonal pillars ( Chang et al, 2018 ; Pingle et al, 2018 ). Although the patterns, materials, and strains used vary, most patterns inhibit bacterial adherence more significantly at a smaller size.…”