Abstract
Biofunctionalization of Ti6Al4V alloy with metallic agents like Ag or Cu is a promising approach to add antibacterial properties and thus to reduce the risk of implant failure. This research investigates the in-situ alloying of Ti6Al4V(ELI) with 3 at.% Cu powders using Laser Powder Bed Fusion (L-PBF). The morphology and geometrical characteristics of the single tracks and layers were studied. Laser powers of 170 W and 340 W, and scanning speeds ranging from 0.4 to 1.4 m/s and 0.8–2.8 m/s were implemented. Single track results showed balling effect and humping at high scanning speeds, 1.4 m/s and 1.6 m/s, for each laser powder respectively. Conversely, keyhole formation occurred at lower scanning speeds of 0.4–0.6 m/s for 170 W laser power, and below and 0.8 m/s for 340 W laser power. For both laser powers, single layers resulted in smoother surfaces at lower scanning speeds. These results were used for the development of optimal process parameters for 3D cubes with 99.9 % density. Optimal process parameters were found for 170 W and 340 W laser powders at 0.7−0.9 and 1.0–1.2 m/s scanning speeds, respectively.In-situ alloying by L-PBF was challenging and a homogeneous distribution of Cu within the alloy was hard to achieve. The increase in laser power from 170 to 340 W resulted in small increase in homogenization. Microstructural analyses after stress-relieving treatment showed the presence of α’ and β phases, as well as CuTi2 intermetallic precipitates. The finer microstructure together with CuTi2 intermetallic precipitates resulted in an increase in hardness. This study demonstrates the potential for printing in-situ alloyed Ti6Al4V(ELI)- 3 at.% Cu for biomedical applications. However, further studies are required to determine the effectiveness of antibacterial properties.
Highlights
Metallic biomaterials such as stainless steel, titanium and cobalt chromium alloys are widely used for implantable devices for replacement of structural components of the human body
This study demonstrates the potential for printing in-situ alloyed Ti6Al4V(ELI)- 3 at.% Cu for biomedical applications
Ma et al [7] and Xu et al [17] have found that the cytocompatibility of Ti6Al4V with 5−6 wt.% Cu was equivalent to Ti6Al4V alloy, which is generally recognized as a safe material and was approved for biomedical applications
Summary
Metallic biomaterials such as stainless steel, titanium and cobalt chromium alloys are widely used for implantable devices for replacement of structural components of the human body. Titanium (Ti) alloys are less susceptible to bacterial adhesion than stainless steel [1], but commercially available Ti alloys do not exhibit antibacterial capability. The coating of implants with antibacterial elements, like silver (Ag), zinc (Zn) and copper (Cu), is proven to be a promising approach to prevent bacterial infection [4]. Adding antibacterial properties to stainless steels, cobalt-chromium and titanium alloys by the addition of Cu has been reported in several invitro and in-vivo studies [5,6,7,8,9,10,11,12]. Aureus, which are the main pathogenic microbes responsible for implant-related infections [18], was confirmed for LPBF Ti6Al4V(ELI)-1 at.% Cu alloy surfaces [19]
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