Search Results (446)

The long-term success of implant-supported prostheses (ISPs) is strongly influenced by material selection, which affects stress distribution within the implant system and surrounding cortical bone. This study aimed to assess the biomechanical behavior of a four-unit ISP supported by two implants in the posterior region, using different framework and superstructure material combinations through dynamic finite element analysis (FEA). Methods: A three-dimensional (3D) edentulous mandibular model was created using Mimics software, with two implants placed in the first premolar and second molar regions. Four framework materials—titanium (Ti), glass fiber–reinforced composite (GFRC), 3Y-TZP zirconia, and polyether ether ketone (PEEK)—were combined with two superstructure materials, 5Y-TZP zirconia and resin-matrix ceramic (RMC), forming eight groups. Dynamic loading simulated chewing forces, and stress distribution was analyzed using the von Mises criterion. Results: The results demonstrated that 3Y-TZP zirconia frameworks generated the highest stress values across implants, abutments, and cortical bone. RMC crowns consistently produced lower stress than 5Y-TZP zirconia across all the groups. PEEK showed the highest displacement, followed by GFRC, zirconia, and Ti. Conclusion: Materials with higher Young’s modulus tended to exhibit greater stress transfer to the implant, implant components, and cortical bone. In contrast, polymer-based materials may show a tendency toward greater deformation and displacement compared with metallic and ceramic materials. Full article

Background/Objectives: i-Factor™ Bone Graft is a composite bone substitute containing P-15 synthetic collagen fragment that has demonstrated noninferiority to local autograft in single-level anterior cervical discectomy and fusion (ACDF); however, direct head-to-head comparisons with demineralized bone matrix (DBM) using contemporary 3D-printed titanium cages are lacking. The aim of this retrospective study was to compare radiographic fusion rates, segmental stability, and clinical outcomes between i-Factor™ and DBM in single-level ACDF, with a particular focus on the early time course of fusion. Methods: A retrospective propensity score-matched cohort study was conducted in patients with single-level cervical degenerative disc disease (cervical disc herniation, cervical spondylotic radiculopathy, or cervical spondylotic myelopathy) operated between December 2021 and January 2024 at a single tertiary care hospital. Seventy-six consecutive patients undergoing single-level ACDF with 3D-printed titanium cages were matched 1:1 (i-Factor™ vs. DBM) on age, sex, and operative level. Fusion status was assessed by serial dynamic radiographs at 1, 3, 6, and 12 months and by 3D-CT at 12 months in all patients (with additional CT at earlier timepoints when plain films were equivocal), by two independent spine surgeons blinded to graft type; inter-rater agreement (Cohen’s κ) was computed. Results: Mean follow-up was 18.1 months. Fusion rates for i-Factor™ at 3, 6, and 12 months were 94.7%, 100%, and 100%, respectively, compared to 71.1%, 84.2%, and 94.7% for DBM. The differences were statistically significant at 3 months (p = 0.047) and 6 months (p = 0.012), but not at 12 months (p = 0.493). Inter-rater agreement was almost perfect (κ = 0.86–1.00). No adverse reactions or device-related complications were observed. Conclusions: In this matched cohort, i-Factor™ was associated with significantly faster fusion than DBM in single-level ACDF, with similar 12-month fusion rates. No adverse reactions were observed, although the sample size is insufficient to exclude rare complications. Full article

To improve the visible-light response and antibacterial performance of titanium dioxide, a TiO₂/GO/CdS mesoporous nanocomposite was prepared via an ultrasound-assisted sol–gel method in this study. Systematic characterizations including XRD, XPS, SEM, TEM, BET, UV-Vis DRS and FTIR were carried out to analyze the structure, morphology and optical properties of the material. The results show that the composite exhibits a typical mesoporous structure with a specific surface area of 197.0962 m²/g and a pore size distribution of 2–14 nm. CdS is successfully doped into the TiO₂ matrix and forms a heterostructure with GO. UV-Vis diffuse reflectance spectra indicate that the synergistic effect of CdS and GO significantly broadens the visible-light absorption range of TiO₂ and suppresses the recombination of photogenerated carriers. Antibacterial tests using Escherichia coli as the target strain demonstrate that the TiO₂/GO/CdS composite exhibits remarkably better visible-light photocatalytic bactericidal activity than pure TiO₂ and the TiO₂/GO composite. This work provides a new strategy for the modification of TiO₂-based photocatalytic antibacterial materials, and the as-prepared composite shows promising application prospects in the antibacterial field. Full article

Titanium matrix composites (TMCs) are increasingly vital in aerospace for their high specific strength and wear resistance, with compositional gradient design serving as a key strategy to mitigate thermophysical mismatches between ceramic and metal phases. This study utilized laser-directed energy deposition with concurrent wire-powder feeding (LDED-WP) to fabricate TiC/Ti6Al4V gradient composites, employing a laser power of 2700 W, wire feed rates of 110–150 cm/min, and calibrated powder feed rates ranging from 50.22 to 497.13 g/h. Along the build direction, the TiC content was progressively increased from 10 wt.% to 60 wt.%. Investigations into microstructural evolution revealed that the reinforcement morphology transitions from chain-like eutectic TiC to dendritic primary TiC, while the lamellarα-Ti width refines significantly from 4.07 ± 1.15 μm to 0.45 ± 0.29 μm. EBSD analysis confirmed that higher TiC concentrations weaken the characteristic <001> solidification texture, reducing intensity from 11.24 to 7.64. Furthermore, KAM analysis highlighted that thermal expansion and elastic modulus mismatches trigger substantial geometrically necessary dislocation (GND) accumulation at interfaces. Consequently, Vickers hardness improved by 164% along the gradient, peaking at 950 HV. Although the composite achieved an ultimate tensile strength of 630 MPa, the elongation was limited to 2.4% due to crack nucleation in TiC-rich regions and interfacial instability. Full article

Cu–TiO₂ nanoparticles of a broad range of compositions with 0, 0.002, 0.005, 0.02, 0.05, 0.2, 0.5, 1.0, 2.0, 3.0, 5.0, 7.0 and 10.0 mol% Cu were synthesized via the sol–gel method using copper (II) acetate and titanium tetraisopropoxide (TTIP) precursors at a low hydrolysis ratio of H = 1.25, which favours homogeneous TiO₂ nucleation and Cu dispersion in the host matrix at nanoscale. The precipitated materials were dried at 80 °C and calcined at 450, 500, and 550 °C to form crystalline nanopowders, whose photocatalytic activity was evaluated on the decomposition of a representative pollutant, methylene blue (MB), in aqueous solutions under UVA and sunlight illuminations. The compositions with small Cu content of ~0.05 mol% showed the highest activity. A gain of activity over pure titania of 4 times after calcination at 450 °C, 2.5 times at 500 °C and 20% at 550 °C was measured under UVA illumination. Even higher gain of activity observed under sunlight illumination might be due to an extension of action spectrum to the visible range due to intra-gap defect states produced by Cu²⁺ insertion. The time-resolved microwave conductivity (TRMC) measurements of the photoinduced charges relaxation suggest that both excessive calcination temperature and Cu content decrease the activity due to Cu-defects clustering. Modelling relates the activity to the photoinduced electron-hole pair separation; the optimal Cu content is explained by accessibility of the recombination centre by a conduction band (CB) electron. Accordingly, an increase in calcination temperature resulted in a longer pathlength of CB electron. Full article

SiC fiber-reinforced aluminum matrix (SiC_f/Al) composites have the potential to replace titanium alloys for fan/compressor blades due to their low density and favorable high-temperature performance. In this study, thermal exposure and thermal cycling tests were conducted to simulate service environments and to clarify their effects on the microstructure and interfacial properties of a SiC_f/AlFe5Si2 composite. Thermal exposure was performed at 260–450 °C for 20–100 h, and thermal cycling was carried out between 300 or 350 °C (1 h dwell) and room temperature for 20–100 cycles. Interfacial shear strength was evaluated by push-out tests, while microstructural evolution was examined using SEM, TEM/EDS, and XRD. Three-dimensional finite element simulations were used to assess mismatch-driven residual-stress distributions during the cooling stage after thermal excursion. The results showed that interfacial shear strength decreased with increasing exposure temperature/time and degraded more severely under thermal cycling than under isothermal exposure at the same temperature. A rapid loss of interfacial strength occurred above ~400 °C, associated with significant interfacial-layer thickening and the formation of brittle Al_xSiO_y phases. The interfacial reaction layer followed parabolic growth kinetics, yielding a preliminary apparent activation energy of Q ≈ 150 kJ/mol estimated from two isothermal temperatures. The simulations indicated large opposing stresses between the matrix and the carbon-rich layer, supporting a mechanical driving force for interfacial debonding; however, heating/dwell time-dependent effects were not explicitly modeled and are discussed as limitations. These findings provide quantitative guidance for defining service-temperature limits and improving interfacial thermal stability in SiC_f/AlFe5Si2 composites. Full article

High-manganese steel has emerged as a potential alternative material to austenitic stainless steel for liquid hydrogen storage and transportation environments, owing to its superior mechanical characteristics and limited hydrogen diffusivity. However, its hydrogen embrittlement (HE) susceptibility limits its engineering applications. This study investigates the effect of microstructural regulation through trace titanium (Ti, 0.021 wt%) addition on HE resistance in high-manganese steel. By means of Electron Backscatter Diffraction (EBSD), TEM, SEM, and Slow Strain Rate Tensile (SSRT) tests, the effects of Ti on the microstructure, mechanical properties, and HE susceptibility of high-manganese steel are systematically investigated. The results show that the addition of Ti did not significantly alter the average austenite grain size or phase composition, but it generated a large number of Ti(C,N) nanoscale precipitates with sizes ranging from 20 to 70 nm within the matrix. The elongation loss of the 25Mn-Ti specimen was significantly lower than that of the 25Mn specimen when hydrogen-charged for 72 h, decreasing from 18.4% to 9.3%. The fracture surfaces consistently exhibited ductile dimple morphology, whereas 25Mn steel demonstrated significant cleavage-induced brittle fracture. EBSD analysis revealed that hydrogen-charged 25Mn-Ti steel exhibited higher Kernel Average Misorientation (KAM) value retention rate and more uniform grain strain distribution, indicating enhanced microstructural deformation compatibility. The main mechanism was that Ti pre-formed nanoscale Ti(C,N) precipitates during the preparation of 25Mn high-manganese steel, which played a key role in inhibiting HE. These precipitates altered hydrogen diffusion behavior and distribution patterns, reduced stress concentration levels, and inhibited hydrogen-induced crack initiation. This work is of great significance for improving the HE resistance of high-manganese steels. Full article

Developing membranes with superior antifouling properties is crucial for efficient and sustainable water treatment. In this study, polysulfone (PSM) composite membranes were fabricated by incorporating hydroxylated titanium nanotubes (TNT@OH) via the non-solvent-induced phase separation method. The hydroxylation of TNTs enhanced their dispersion in the polymer matrix and promoted strong polymer–nanoparticle interactions. Comprehensive characterization using FTIR, XRD, TGA, FESEM, and AFM confirmed the successful integration of TNT@OH, resulting in membranes with improved hydrophilicity, porosity, and thermal stability. The contact angle decreased from ~88° for neat PSM to ~50° at 7 wt% TNT@OH, while surface free energy increased significantly. Mechanical strength and flexibility were also enhanced at optimal TNT@OH loadings (3–5 wt%), owing to uniform dispersion and strong interfacial bonding. Filtration experiments using humic acid (HA) and natural organic matter (NOM) demonstrated remarkable improvements in water flux, rejection efficiency, and fouling resistance. The composite membranes achieved HA rejection rates of up to 98%, with reduced irreversible fouling and higher flux recovery ratios across multiple filtration–cleaning cycles. The proposed antifouling mechanism is attributed to the formation of a stable hydration layer by surface hydroxyl groups, which prevents foulant adhesion and facilitates cleaning. These findings suggest that incorporating TNT@OH into polysulfone membranes is a promising approach for developing high-performance ultrafiltration membranes with enhanced permeability, mechanical robustness, and long-term antifouling stability, thereby making them suitable for advanced water purification applications. Full article

Modification of PLA with functional nanoparticles is a promising approach for imparting new properties to the material. In this work, titanium nanoparticles (Ti NPs) and titanium dioxide nanoparticles (TiO₂ NPs) were synthesized by laser ablation and characterized by dynamic light scattering, spectrophotometry, and transmission electron microscopy. The average hydrodynamic diameter of Ti NPs was 12 nm, while that of TiO₂ NPs was 24 nm; both dispersions possessed a positive zeta potential (23–27 mV) and spherical morphology. L-PLA composite films containing 0.1 wt.% Ti NPs or TiO₂ NPs were obtained by solution casting. Atomic force and modulation-interference microscopy confirmed the uniform distribution of nanoparticles within the polymer matrix, although partial aggregation was observed. The introduction of TiO₂ NPs increased the water contact angle. Mechanical testing revealed a significant reinforcing effect: the addition of 0.1 wt.% NPs increased the Young’s modulus by 62–68% and the ultimate tensile strength by 16–18% while maintaining a ductile fracture pattern with elongation at break up to ~8%. Both types of composites generated reactive oxygen species (ROS) in aqueous solutions: Ti NPs increased H₂O₂ production by 5.5 times and TiO₂ NPs by 4.9 times, and they also induced the formation of hydroxyl radicals. The accumulation of 8-oxoguanine in DNA and long-lived oxidized protein species confirmed the materials’ ability to cause oxidative damage to biomacromolecules. For E. coli, growth inhibition reached 40.5% (for composites with Ti NPs) and 71% (for composites with TiO₂ NPs). The effect was even more pronounced for S. aureus, where inhibition levels were approximately 70% and 80%, respectively; flow cytometry confirmed the strong bactericidal effect, showing that materials containing TiO₂ NPs increased the proportion of dead cells to 25% for E. coli and ~68% for S. aureus. Cytotoxicity assessment on human fibroblasts (HSF) demonstrated the high biocompatibility of neat L-PLA and composites with Ti NPs (viability > 95%) and with TiO₂ NPs (viability ~93%). The obtained results indicate that L-PLA-based composites with Ti NPs and TiO₂ NPs exhibit pronounced ROS-mediated antibacterial activity without additional UV irradiation. These findings position these materials as highly promising candidates for active biodegradable food packaging to extend shelf-life and for biomedical devices, such as wound dressings and implants, where reducing the risk of bacterial colonization is critical. Full article

Composite materials with Ti or Ti alloy reinforcement in a Zn matrix are new, promising materials with potential applications in implantology. Infiltrating zinc into the porous titanium reinforcement of a designed implant could improve its osseointegration. In this field, it is important to avoid the formation of brittle intermetallics; therefore, understanding their growth is fundamental. This work focuses on characterizing the Ti-Zn intermetallic phases at the interface of the TiAlV/Zn and Ti/Zn composites. Samples were prepared by immersing the Ti-6Al-4V or Ti bulk material in zinc melt at various temperatures. After various dwell times, the samples (pieces of Ti-6Al-4V or Ti in the molten zinc) were removed from the furnace and cooled in air. The sequence of evolution of intermetallic phases was observed to be dependent on dwell time at selected temperatures. The influences of surface treatment methods on the boundary structure were also tested. Full article

Titanium alloys are widely used in dental implants due to their excellent mechanical properties. However, their inertness and poor antibacterial activity cause interfacial loosening and failure, shortening service life. This study integrates surface microtexturing with coating technologies, employing modified light-curing composite resins to boost the bioactivity of medical titanium alloys via surface modification. The results reveal that surface microtexturing enlarges the coating-substrate contact area by 42.5% compared with rough surfaces, concurrently diminishing stress per unit area, and the coating on microtextured Ti-6Al-4V (TC4) surfaces achieves adhesion with a damaged area of only 0.5%, thereby notably enhancing adhesion between the coating and TC4 matrix. In comparison, with rough surfaces (surface roughness of 0.658 μm), smooth TC4 planes (surface roughness of 0.014 μm) show a significantly reduced bacterial colony count (from 130 ± 6 to 42 ± 3) with an antibacterial rate of 67.7%, as the water contact angle on TC4 surfaces increases with decreasing roughness (reaching 80.95° on the smoothest surface), making bacterial adhesion more challenging and reducing colonization. The composite resin coating based on a mixture of titanium-doped hydroxyapatite and titanium dioxide (Ti-HA/TiO₂) further improves the antibacterial rate to 74.6% through a photocatalytic synergistic effect and endows TC4 with excellent remineralization capacity—mineralization deposits appear on the coated surface after 3 days of immersion in artificial saliva, while no obvious deposits are found on uncoated rough and smooth surfaces even after 7 days—thereby enhancing its bioactivity effectively. This study on the modification of Ti-based implant surfaces will enrich the field by introducing new technologies and methodologies. These advancements provide a theoretical basis for improvement of the remineralization capacity and antibacterial properties of Ti-based dental implants, thereby promoting broader biomedical applications. Full article

Pesticides are a major cause of water contamination, making this issue a major environmental and public health concern. In this context, the development of advanced and effective remediation materials is needed. In this study, a titanium-functionalized magnetic silica aerogel (AG-Ti@Fe₃O₄-SA) was successfully prepared via microfluidics and evaluated for water decontamination. The structural and compositional features of the aerogel were determined using XRD, FT-IR, RAMAN, SEM, TEM, BET, and DLS, confirming the formation of the aerogel with dispersed Fe₃O₄-SA nanoparticles and the successful incorporation of titanium within the aerogel matrix. Regarding decontamination potential, the aerogel was tested against a pesticide mixture, yielding pesticide-dependent removal efficiencies (16–100%). Notably, the aerogel exhibited a high affinity for organophosphorus pesticides and a moderate affinity for polar compounds, whereas bulky hydrophobic pesticides showed lower adsorption. In vitro, the aerogel induced a moderate decrease in HaCaT cell viability after 48 h of exposure, accompanied by a slight increase in lactate dehydrogenase release, while HEK293 cells remained largely unaffected, indicating a cell-type-dependent biological response. Overall, the findings from this screening-level study recommend AG-Ti@Fe₃O₄-SA aerogel as a promising selective adsorbent for pesticide removal. Full article

Titanium matrix composites reinforced with carbon nanotubes (CNTs) have attracted significant attention due to their potential to overcome the inherent limitations of titanium alloys in hardness, wear resistance, and strength–toughness balance. With the rapid development of additive manufacturing (AM) technologies, the integration of CNT reinforcements into titanium matrices provides new opportunities for fabricating high-performance lightweight components. This review systematically summarizes recent progress in the preparation and application of CNT-reinforced titanium matrix composites for AM. Key powder preparation strategies, including mechanical mixing, chemical coating, and in situ growth methods, are critically compared in terms of CNT dispersion uniformity, structural integrity preservation, powder flowability, and process compatibility. The influence of CNT incorporation on AM behavior and final material performance is discussed, with particular emphasis on multiscale strengthening mechanisms such as enhanced laser absorption, load transfer effects, grain refinement, and dispersion strengthening induced by TiC formation. Current challenges mainly involve achieving homogeneous CNT distribution, controlling interfacial reactions, and balancing dispersion efficiency with structural damage. Future research directions are proposed, focusing on advanced powder engineering techniques, interface regulation strategies, and deeper understanding of the relationships between processing parameters, microstructure evolution, and mechanical properties. This work provides a comprehensive reference for the design and fabrication of next-generation CNT-reinforced titanium-based materials. Full article

This study involves the addition of B₄C particles to TC4 powder to fabricate B₄C-reinforced titanium matrix composite coatings on an AISI 304L substrate using a laser cladding process. The effects of B₄C addition (0–12 wt.%) on microstructure, microhardness, wear, and corrosion performance were systematically investigated. Results indicate that the composite coating with 9 wt.% B₄C exhibits optimal properties, achieving a peak microhardness of 600 HV_0.2 and a wear rate of 2.82 × 10⁻⁴ mm³/N·m, representing a 58.22% reduction compared to the pure TC4 coating. Electrochemical tests in 3.5 wt.% NaCl solution reveal a significant positive shift in corrosion potential and reduced corrosion current density with increasing B₄C content, confirming enhanced corrosion resistance, and the improved performance is attributed to grain refinement and dispersion strengthening by B₄C particles. This work provides a feasible strategy for enhancing the surface properties of 304L stainless steel under demanding wear and corrosive environments. Full article

Friction stir-welding (FSW) is widely recognized as a modern solid-state technology used to join dissimilar materials by solid-state mechanical mixing. Such mechanical mixing can be exploited to fabricate in situ composite structures through solid-state deformation mechanisms. The present investigation highlights the microstructural evolution and mechanical properties of an in situ composite structure fabricated by FSW of aluminum (Al) to titanium (Ti) incorporating a thin Nickel (Ni) interlayer. A 0.1 mm thick Ni foil was placed across the full butt interface between 4 mm thick Al and Ti plates before friction stir-welding. Properties of the composite were investigated in detail, and the results revealed that fragmented Ti and Ni particles of different sizes were consolidated in the weld nugget. Al, on the other hand, exhibited substantial microstructural refinement and developed an equiaxed microstructure with random grain orientation, mixed grain boundaries and low micro-strain accumulation in the weld nugget. At the processing temperature, Al reacted with both Ti and Ni to form multiple intermetallic compounds. Tensile testing indicated that the tensile properties of the weld were close to those of the base aluminum. This retention of mechanical properties in spite of recrystallization is attributed to the following mechanisms: (1) Ti and Ni undergo severe deformation, forming fine particles with varying sizes and shapes; (2) at particle interfaces, diffusion and chemical reactions produce interlayers and intermetallic compounds; (3) these particles are consolidated within dynamically recrystallized Al, imparting composite characteristics to the weld nugget; and (4) the particles containing intermetallic compounds act as dispersoids in the Al matrix. Quantitatively, the weld retained 98% (104.2 ± 3.3 MPa) UTS and 90% (17.1 ± 1.2) ductility of base aluminum, demonstrating the effectiveness of the Ni interlayer approach in controlling brittle intermetallic formation. Full article