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Medical grade of both titanium (Ti) and Ti6Al4V alloy are recognized as the metallic biomaterials with the better outcomes for clinical repair of bone tissue thanks to their suitable mechanical properties and corrosion resistance. However, those Ti advantages are not enough to avoid failure risks of bone implants; between 5 and 10% of Ti implants fail due to a deficient osseointegration, within 5 years of post-implantation. Most of these failures indicate the necessity of getting a better biomechanical-biofunctional balance. Microstructural and tribo-mechanical characterizations were performed on Ti6Al4V samples obtained by selective laser melting and subjected to different surface treatments (thermal stress relief, acid etching, chemical treatment and thermo-chemical treatment). Scanning electron microscopy and X-ray diffraction were used for detailed characterization of the elemental composition, phase analysis and surface morphology. Micro-hardness and scratch tests were employed to evaluate the tribo-mechanical properties, which were improved after consecutive surface treatments. Protuberances with spherical morphology, as a remainder of the original powder, were present on the surface. The resulting modified surfaces were constituted by rutile (major phase) and anatase (minor phase). Submicro-nano-topographies were obtained after the chemical and thermochemical treatments. [ABSTRACT FROM AUTHOR]

Tooth loss is common in patients struggling with dental cavities, periodontal diseases, and tumors, as well as those who abuse tobacco or drugs. In this scenario, dental implants have become the primary treatment option for complete or partial tooth loss. Dental implant failure can be caused by stress shielding phenomenon, poor osseointegration, or to bacterial infections. In the present study, a joint solution to these limitations is proposed using a variety of porous β-titanium substrates using powder Ti35Nb7Zr5Ta alloy and employing the spacer-holder approach (ammonium bicarbonate) to obtain a variety of porosity percentage (30, 40, and 50 vol%), and pore diameters in 100–200 μm, that has been characterized in terms of its size distribution, density, morphology, chemical composition, compaction ability and Vickers micro-hardness. Furthermore, porosity, microstructure (Archimedes and image analysis) and tribomechanical behavior (P-h curves and scratch tests) experiments were performed to study and characterize the porous substrates. Polyvinyl alcohol (PVA)/poly-ε-caprolactone (PCL) containing silver nanoparticles (AgNPs), as antibacterial composite, was employed to infiltrate β-Ti disks. Scanning electron microscopy was used to determine the coating morphology, thickness, and infiltration of the porous substrates. Wettability and SBF experiments were also carried out to investigate hydrophobicity and potential bio-functionality. The results suggested how the porosity of the β-Ti alloy affects the mechanical characteristics and the wettability of the substrate that was successfully infiltrated to exert an antimicrobial behavior. [Display omitted] • Novel beta porous titanium implant coated with therapeutic biocomposite. • Bio-functional antibacterial behavior of PVA/PCL/AgNPs biocomposite. • A solution to improve the tribomechanical and biofunctional behavior of metal implants. [ABSTRACT FROM AUTHOR]

Residual stresses in the substrate and in the PVD coating have a significant influence on the coating adhesion and lifespan of machining as well as forming tools. Therefore, the understanding and control of the system's residual stresses will lead to a better performance of the coated components. Moreover, although investigations were conducted in the field of stress analysis of PVD coatings, they do not focus on interdependencies of residual stresses in the substrate and in the coating. In this investigation, three different metallographically prepared substrates were used. SiC grinding, diamond grinding, and SiC grinding and plasma nitriding preparations were selected, due to the substantial differences in their final residual stress states. Additionally, a Ti/TiAlN multilayer coating and a reference TiAlN monolayer were deposited on each pre-treated substrate. Their initial and final residual stress states were measured by means of X-ray diffraction. In addition to the residual stress analyses, tribo-mechanical tests, such as nano-indentation, ball-on-disc, and scratch tests were performed in order to correlate the results with these residual stress states. [ABSTRACT FROM AUTHOR]