Ke Zhang

Titanium (Ti) is a biologically inert material, lacking antibacterial activity and osteoconductive properties, which may lead to implant failure. To address these issues, a surface-modified film is developed that combines inherent antibacterial properties with synergistic antibacterial functionality in response to Near-Infrared (NIR) light. Titanium Dioxide (TiO[ ] nanorods were prepared on a titanium surface via the hydrothermal method. Utilizing the physical perforating properties of TiO ₂ nanorods combined with the specific ability of Gallium (Ga) to disrupt bacterial Iron (Fe) metabolism, different concentrations of Ga[ ] were doped. The microstructure, composition and related physicochemical properties of the film layer were investigated. To further enhance antibacterial efficacy, photothermal therapy and photodynamic therapy were integrated by irradiating the film with 808[ ]nm NIR light. Results demonstrated that Ga-doped TiO ₂ films exhibited outstanding synergistic antibacterial activity under 808[ ]nm NIR irradiation. Specifically, the highest antibacterial rate of irradiated samples against Escherichia coli (E. coli) reached 98.1%, and the highest antibacterial rate against Staphylococcus aureus (S. aureus) reached 98.5%. Furthermore, the films demonstrated favorable osteoconductive properties in in vitro mineralization experiments. This approach offers a new strategy for addressing issues of implant infection and inadequate osteogenic performance.

The high incidence of peri-implant inflammation has become the main cause of implant treatment failure, and the improvement of the antibacterial properties of clinical oral materials is a key demand in the field of stomatology. To address this issue, we developed a coating on the surface of titanium (Ti) based on molybdenum disulfide (MoS[ ], doped with polyphenols and copper (Cu) ions and investigated its antibacterial properties under 808[ ]nm near-infrared (NIR) light irradiation. The corresponding chemical composition, surface morphology, hydrophilicity and release behavior were investigated, demonstrating the composite coating was successfully applied to the Ti. The MoS ₂ /Cu composite shows a high degree of photocatalytic activity, resulting in the enhanced generation of reactive oxygen species (ROS). The addition of tannic acid (TA) enhanced the Cu ion loading capacity of the coating, and further strengthened its antibacterial properties. Moreover, the MoS ₂ -based coating also demonstrates a specific photothermal effect. In vitro experiments indicate that after 10 min of 808 nm NIR, antibacterial rates of 97.6% for Staphylococcus aureus (S. aureus) and 98.7% for Escherichia coli (E. coli) were achieved. Therefore, this study provides a novel surface modification scheme for the early prevention of implant-related infections, which helps to reduce the risk of secondary surgeries and improve the clinical success rate of implant treatment.

Aluminum alloys are prone to pitting and intergranular corrosion during use, which greatly limits their large-scale application. This study explores micro-arc oxidation (MAO) coatings on 1.5[ ]wt.% CNTs/2024Al composites to improve corrosion resistance. Using a Na ₂ SiO ₃ –NaOH electrolyte at 430[ ]V for 12[ ]min, MAO coatings were prepared. SEM shows denser surfaces with smaller pores in CNTs-reinforced coatings due to CNTs optimizing discharge channels. XRD confirms [ ]-Al ₂ O ₃ and [ ]-Al ₂ O ₃ phases, with higher crystallinity in CNTs/2024Al coatings. EDS detects C elements, indicating CNTs participation in film formation. Electrochemical tests in 0.5[ ]wt.% NaCl show CNTs/2024Al-MAO has a lower corrosion current density ([ ][ ]A/cm ² ) and higher charge transfer resistance, demonstrating superior corrosion resistance. MAO with CNTs offers a viable strategy for enhancing Aluminum Matrix Composites (AMCs) durability in harsh environments.

A major cause of clinical failure for Ti alloys employed as biomaterials lies in their lack of antimicrobial activity and failure to achieve effective osseointegration. To address these two critical limitations, this work integrates antibacterial silver nanoparticles (Ag NPs) with piezoelectric BaTiO ₃ (BTO) coatings, aiming to simultaneously overcome both deficiencies. The Ag-BTO coatings were fabricated via a combined anodic oxidation-hydrothermal method. By leveraging the biomimetic piezoelectric properties of BTO and the controllable antibacterial activity of Ag NPs, this strategy not only ensures long-term antimicrobial performance but also promotes mineralization through the piezoelectric effect. Experimental results demonstrate that the Ag-BTO coatings exhibit robust antimicrobial efficacy; notably, ultrasonic treatment further enhances their capacity to induce hydroxyapatite deposition. Specifically, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reach 87.38% and 99.27%, respectively. Overall, this surface modification approach provides a practical solution to enable the stable and successful clinical application of titanium-based bone implants.

Dual-phase (DP) steels are widely used in automotive structures due to their excellent strength–ductility balance. This study examines how silicon content and continuous annealing parameters affect the microstructure, mechanical properties, and hydrogen embrittlement (HE) behavior of DP1500 steel. Two steels, 05DP (0.5% Si) and 15DP (1.5% Si), were processed under annealing temperatures of 800–850 °C and over-aging temperatures of 240–300 °C. Higher annealing temperatures increased austenite formation and produced more martensite after cooling, leading to higher strength but reduced ductility at 850 °C due to martensite coarsening. Increasing the over-aging temperature coarsened carbides and reduced strength yet stabilized retained austenite and improved ductility through the TRIP effect. An increase in silicon content suppressed carbide precipitation, promoted carbon enrichment in austenite, refined the ferrite–martensite structure, and significantly enhanced both strength and elongation. Consequently, 15DP steel exhibited superior mechanical properties compared to 05DP steel, exhibiting 90–100 MPa higher tensile strength (+6.2–7.0%), 55–65 MPa higher yield strength (+5.3–6.2%), and 1.4–1.8 percentage points higher total elongation (+10–14%), resulting in a 16–20% increase in the strength–ductility balance (Rm × A). However, due to the relatively high hydrogen embrittlement susceptibility of fresh martensite formed either by the TRIP effect during deformation or after over-aging, 15DP steel did not exhibit substantially improved HE resistance despite its higher retained austenite fraction.

New grades of dual-phase (DP) steels with ultimate tensile strength (UTS) up to 1500 MPa have been developed using a continuous annealing process. This study investigates the effects of over-aging temperature and NbC precipitates on the microstructure and hydrogen embrittlement of these DP steels. Increasing the over-aging temperature promotes carbide coarsening, which reduces tensile strength, but simultaneously stabilizes retained austenite by inhibiting martensite transformation and enhances ductility through the TRIP effect. Compared to the reference DP steel, the Nb-added DP steel exhibits further strength enhancement due to fine-grain strengthening and precipitation strengthening. Results from slow strain rate tensile (SSRT) and thermal desorption spectroscopy (TDS) tests demonstrate that the Nb-added DP steel possesses superior resistance to hydrogen embrittlement. This improvement is primarily attributed to the hydrogen trapping effect of NbC precipitates, complemented by their grain refinement capability.

Shape-memory alloys (SMAs) inherently possess dual actuation and sensing capabilities. Excellent superelasticity and fatigue resistance are crucial for the service reliability and stability of SMAs. This review summarizes the microstructure, functional properties, strengthening mechanisms, and failure mechanisms of the most widely used NiTi-based SMA, Gum Metals, novel NiMn-based SMAs, and newly developed Fe-based alloys. The high strength and toughness of NiTi SMA contribute to its excellent fatigue performance, achieved through microalloying, structural design, and grain size engineering. Texture toughening strategies overcome the intergranular brittleness inherent in traditional NiMn-based SMAs. Alloy design strategies enable the development of iron-based superelastic alloys exhibiting near-constant critical stress temperature dependence, overcoming the conventional limitation in superelastic alloys where critical stress decreases significantly with decreasing temperature. The principles and implementation strategies for controlling superelasticity and superplasticity in SMAs provide valuable guidance for designing and applying structure-function-integrated materials.

NiCoCrAlY coatings are commonly used as bond-coat in thermal barrier coatings due to their excellent high-temperature oxidation resistance and suitable thermal expansion coefficient between the superalloy substrate and ceramic top layer. Previous studies have shown that the NiCoCrAlY coatings prepared by cold spray (CS) exhibit excellent comprehensive properties. In the process of cold spray, the solid particles impact onto the substrate with a high velocity, powder particles and the substrate undergo plastic deformation, and the coating is deposited finally. When the velocity of the impacted particles reaches a certain value (critical velocity), the particles can be effectively deposited on the substrate. Due to the short impact time and large plastic deformation of the cold spray process, the process is difficult to be observed in the actual experiment process in real time. Therefore, the current work has used the explicit dynamics method in finite element numerical simulation to simulate the deposition behavior of the particle during the cold spray process. By changing the impact velocities and sizes of particles, the changes in temperature (TEMP), equivalent plastic strain (PEEQ), deformation characteristics of the particle and substrate after particles being completely deposited on the substrate have been obtained. The critical velocity of particle deposition is about 600 m/s, and the larger the particle, the easier it is to deposit. And the current modeling and simulation work provided the theory instruction for the preparation of NiCoCrAlY coatings with excellent performance via cold spray.