Conventional Ti Research Articles

Compact laser-driven plasma X-ray source for time-resolved diffraction, spectroscopy and imaging experiments at ELI Beamlines.

In this work, experimentally measured characteristics of a kilohertz laser-driven Cu plasma X-ray source that was recently commissioned at the ELI Beamlines facility are reported. The source can be driven either by an in-house developed high-contrast sub-20 fs near-infrared terawatt laser based on optical parametric chirped-pulse amplification technology or by a more conventional Ti:sapphire laser delivering 12 mJ and 45 fs pulses. The X-ray source parameters obtained with the two driving lasers are compared. A measured photon flux of the order up to 1012 Kα photons s-1 (4π)-1 is reported. Furthermore, experimental platforms for ultrafast X-ray diffraction and X-ray absorption and emission spectroscopy based on the reported source are described.

Ethanol-assisted synthesis of titanium-rich TS-1 zeolite: a new hexa-coordinated Ti site for efficient propylene epoxidation.

TS-1 (MFI) zeolites are widely utilized in various green oxidation reactions, such as alkene epoxidation and alcohol oxidation. To elevate their catalytic efficacy, strategies such as increasing Ti content or constructing highly active Ti species within zeolite are commonly employed. Here, we synthesized a titanium-rich TS-1 zeolite (Si/Ti ratio of 25.6) with an unprecedented hexa-coordinated Ti species, demonstrating high activity in propylene epoxidation, achieved by utilizing ethanol as a crystal growth modifier through a two-step crystallization strategy. The introduced ethanol regulated the crystallization pathway from the classical to the non-classical route, and enhanced the incorporation of Ti within the TS-1 framework by balancing the insertion of Ti and the crystal growth. The hexa-coordinated Ti species promoted by using ethanol as a crystal growth modifier was identified as Ti(OH2)(OSi)3(OSiOH)2 by means of ultraviolet-resonance Raman spectroscopy, X-ray absorption spectroscopy and theoretical calculations, differing from the conventional Ti(H2O)2(OH)2(OSi)2 in TS-1. The as-prepared TS-1 zeolite was applied in the propylene epoxidation reaction, showing exceptional catalytic activity (H2O2 conv. 35.6%), high 1,2-propylene oxide selectivity (93.3%), and excellent stability. This work introduces an ethanol-assisted synthesis strategy that facilitates the incorporation of a new hexa-coordinated Ti species into TS-1 zeolite that is highly active in oxidation reactions.

The Use of Metallic Elements in Bone Repair Scaffolds

Abstract. Bone repair has been a challenging issue for a long time. Some recent studies focused on the incorporation of metallic elements into scafffolds for improving the performance for bone regeneration. This review explores the use of metallic elements in bone repair scaffolds, focusing on strontium (Sr), silicon (Si), magnesium (Mg) and Titanium (Ti). These elements enhance scaffold properties, promoting bone regeneration. Sr5(PO4)2SiO4 (SPS) bioceramic scaffolds, fabricated through 3D plotting and sol-gel methods, exhibit superior mechanical strength and induce osteogenesis and angiogenesis in vitro. Sr and Si ions within the SPS scaffolds upregulate genes related to cell proliferation, osteogenesis, and angiogenesis. Porous magnesium (Mg) scaffolds, with their biodegradability and ability to stimulate bone formation, offer an alternative to traditional metal implants. Mg scaffolds demonstrate good biocompatibility, physical properties, and osteoinductive potential. Porous titanium (Ti) scaffolds, manufactured through powder metallurgy, address the issue of stress shielding associated with conventional Ti implants. The interconnected pore network and controlled porosity of these scaffolds mimic natural bone, leading to improved biocompatibility and cell interaction.

The Use of TiH2 to Refine Y2Ti2O7 in a Nano Mo-ODS Alloy

Mo-ODS alloys have excellent mechanical properties, including an improved recrystallization temperature, greater strength due to dispersed oxides, and the ability to suppress grain growth at high temperatures. In ODS alloys, the dispersed Y2O3 and added Ti form Y-Ti-O complex oxides, producing finer particles than those in the initial Y2O3. The complex oxides increase high-temperature stability and improve the mechanical properties of the alloy. In particular, the use of TiH2 powder, which is more brittle than conventional Ti, can enable the distribution of finer oxides than is possible with conventional Ti powder during milling. Moreover, dehydrogenation leads to a more refined powder size in the reduction process. This study investigated the refinement of Y2Ti2O7 in a nano Mo-ODS alloy using TiH2. The alloy compositions were determined to be Mo-0.5Ti-0.5Y2O3 and Mo-1.0Ti-0.5Y2O3. The nano Mo-ODS alloys were fabricated using Ti and TiH2 to explore the effects of adding different forms of Ti. The sintered specimens were analyzed through X-ray diffraction for phase analysis, and the microstructure of the alloys was analyzed using scanning electron microscopy and transmission electron microscopy. Vickers hardness tests were conducted to determine the effect of the form of Ti added on the mechanical properties, and it was found that using TiH2 effectively improved the mechanical properties.

Vertical Electric-Field-Induced Switching from Strong to Asymmetric Strong-Weak Confinement in GaAs Cone-Shell Quantum Dots Using Transparent Al-Doped ZnO Gates.

The first part of this work evaluates Al-doped ZnO (AZO) as an optically transparent top-gate material for studies on semiconductor quantum dots. In comparison with conventional Ti gates, samples with AZO gates demonstrate a more than three times higher intensity in the quantum dot emission under comparable excitation conditions. On the other hand, charges inside a process-induced oxide layer at the interface to the semiconductor cause artifacts at gate voltages above U≈ 1 V. The second part describes an optical and simulation study of a vertical electric-field (F)-induced switching from a strong to an asymmetric strong-weak confinement in GaAs cone-shell quantum dots (CSQDs), where the charge carrier probability densities are localized on the surface of a cone. These experiments are performed at low U and show no indications of an influence of interface charges. For a large F, the measured radiative lifetimes are substantially shorter compared with simulation results. We attribute this discrepancy to an F-induced transformation of the shape of the hole probability density. In detail, an increasing F pushes the hole into the wing part of a CSQD, where it forms a quantum ring. Accordingly, the confinement of the hole is changed from strong, which is assumed in the simulations, to weak, where the local radius is larger than the bulk exciton Bohr radius. In contrast to the hole, an increasing F pushes the electron into the CSQD tip, where it remains in a strong confinement. This means the radiative lifetime for large F is given by an asymmetric confinement with a strongly confined electron and a hole in a weak confinement. To our knowledge, this asymmetric strong-weak confinement represents a novel kind of quantum mechanical confinement and has not been observed so far. Furthermore, the observed weak confinement for the hole represents a confirmation of the theoretically predicted transformation of the hole probability density from a quantum dot into a quantum ring. For such quantum rings, application as storage for photo-excited charge carriers is predicted, which can be interesting for future quantum photonic integrated circuits.

A comparative characterization analysis of electrode materials for optimal deposition on copper by advancing electrical discharge coating

This research explores the efficiency of Electrical Discharge Coating (EDC) as an advanced surface modification technique using powder suspension, conventional electrodes, and 3D printed electrodes (3DPE), focusing on Ti6Al4V alloys. Conventional Ti electrodes resulted in 100% titanium content with a thickness of 110 µm, while the powder suspension coating was inadequate. The use of 3D printed electrodes showed promising results, with uniform deposition of 61.20 µm thickness and enhanced surface properties under 10 A current. Further analysis of 3D printed Ti6Al4V EDC revealed a higher Ti percentage of 44.20%, TiC formation of 84.17%, and enhanced microhardness with lower surface roughness. Thorough optimization of 3D printed electrode EDC has been undertaken. The study suggests the potential replacement of traditional electrodes such as powder metallurgy with 3D printed counterparts, advancing surface modification techniques and opening new avenues for materials engineering and manufacturing processes.

Oxygen-induced decomposition of the body-centered cubic HfNbTaTiZr high-entropy alloy

Oxygen-induced decomposition of the body-centered cubic HfNbTaTiZr high-entropy alloy

Effects of Zr and Hf on superelasticity, shape memory effect and microstructure of β-type (Ti–Zr–Hf)–Nb–Sn multi-principal element alloys with low magnetic susceptibility

Effects of Zr and Hf on superelasticity, shape memory effect and microstructure of β-type (Ti–Zr–Hf)–Nb–Sn multi-principal element alloys with low magnetic susceptibility

Microstructure development of Ti scaffold by laser powder bed fusion with chemical polishing and its mechanical properties, biocompatibility

AbstractTitanium (Ti) dental scaffolds are widely used in dental prosthetics due to their excellent mechanical properties and biocompatibility. However, conventional Ti scaffolds manufactured through machining often do not fit perfectly with the bone defect site. Laser powder bed fusion (LPBF) technology enables the personalised manufacturing of custom‐made Ti scaffolds. A custom‐made Ti scaffold was prepared using LPBF and its surface roughness was improved through chemical polishing. To enhance the surface roughness, a nitric acid mixed solution with a specific composition of HF: HNO3:C3H6O3 = 2:2:3 was used. The polishing mechanism was investigated by adjusting the F/Ti ratio to control the formation and dissolution of the oxide film. As a result, the surface of the Ti scaffold after polishing exhibited a smooth and flat appearance compared to the LPBF part, with a reduced surface roughness (Ra) of 1.23 ± 0.19 μm. The custom‐made Ti scaffold also demonstrated favourable mechanical properties, with a bending strength of 335.18 ± 33.62 MPa and stiffness of 2.13 ± 0.21 GPa. Furthermore, in vitro cell tests confirmed the excellent biocompatibility of the custom‐made Ti scaffold. The authors present a feasible strategy for the further clinical application of custom‐made Ti scaffolds, offering enhanced surface properties and addressing the limitations of conventional machining methods.

Construction of Magnesium Phosphate Chemical Conversion Coatings with Different Microstructures on Titanium to Enhance Osteogenesis and Angiogenesis.

Titanium (Ti) and its alloys are widely used as hard tissue substitutes in dentistry and orthopedics, but their low bioactivity leads to undesirable osseointegration defects in the early osteogenic phase. Surface modification is an important approach to overcome these problems. In the present study, novel magnesium phosphate (MgP) coatings with controllable structures were fabricated on the surface of Ti using the phosphate chemical conversion (PCC) method. The effects of the microstructure on the physicochemical and biological properties of the coatings on Ti were researched. The results indicated that accelerators in PCC solution were important factors affecting the microstructure and properties of the MgP coatings. In addition, the coated Ti exhibited excellent hydrophilicity, high bonding strength, and good corrosion resistance. Moreover, the biological results showed that the MgP coatings could improve the spread, proliferation, and osteogenic differentiation of mouse osteoblast cells (MC3T3-E1) and vascular differentiation of human umbilical vein endothelial cells (HUVECs), indicating that the coated Ti samples had a great effect on promoting osteogenesis and angiogenesis. Overall, this study provided a new research idea for the surface modification of conventional Ti to enhance osteogenesis and angiogenesis in different bone types for potential biomedical applications.

A Promising Route to Compact and Economic Sub-15 fs, PW-Level Ti:Sapphire Lasers

In quest of achieving compact and economic PW-level Ti:Sapphire (Ti:sa) lasers with a sub-15 fs pulse duration, a modified hybrid amplification scheme, which combines the optical parametric chirped pulse amplifier (OPCPA) and the chirped pulse amplifier (CPA), is presented and numerically investigated in this paper. The key characteristic of this scheme is that the conventional Ti:sa regenerative amplifier and preamplifier are replaced by a dual-crystal OPCPA front-end, which is spectrally matched with the upstream seed source and the downstream Ti:sa amplifiers and, therefore, can realize a broader spectrum. Moreover, some useful laser techniques are also applied to suppress the spectral gain narrowing and redshift in the Ti:sa CPA chain and to control the residual dispersion in the laser system. This way, fewer amplification stages and pump lasers are required to reach PW-level peak power compared with traditional all-CPA Ti:sa lasers. Numerical results indicate that pulse energy and spectral bandwidth can reach up to ∼22 J and ∼125 nm at full width at half maximum (FWHM), respectively, only by employing three-stage amplifiers. After compression, PW-level lasers with a ∼13.3 fs pulse duration are expected. This work can offer a promising route for the development of compact and economic PW-level Ti:sa lasers.

A novel Zr-based Zr47Ti29Ni21V3 amorphous brazing filler metal for high toughness and strength joining of Ti6Al4V alloy

A novel Zr-based Zr47Ti29Ni21V3 amorphous brazing filler metal for high toughness and strength joining of Ti6Al4V alloy

Impact of Chitosan-Coated Implants on the Alveolar Ridge: Preliminary MicroCT and Radiographic Study in a Canine Model.

To compare crestal bone loss (CBL) 12 weeks after immediate implant placement in the mandible of a canine model between titanium (Ti) implants with a conventional etched surface (SLA type) and Ti implants coated with chitosan (Cht). A total of 48 Ti-Al16-V4 implants (24 experimental and 24 control) with an internally connected tapered screw design were randomly placed into six canine maxillae, 4 per hemiarch. The experimental implants were coated with Cht by immersion and sterilized with ethylene oxide. Primary stability was measured using the Osstell device, and no grafting materials were used. The 3D microCT measurements included crestal bone volume (CBV) and bone volume change in crestal area (ΔCBV), which were considered outcome measures. Parallelized periapical radiographs were also taken at the time of implant placement and after 12 weeks to assess changes in crestal bone levels. In terms of volumetric changes, it was observed that the experimental group showed better results than the control group (P = .049 and P = .303, respectively). Regarding the implant sites, no significant differences were found between the experimental implant sites and control sites. The implants placed at P4 level in the experimental group obtained the best result (P = .041). The linear data obtained from the periapical radiographs indicated greater bone loss in the control group compared to the experimental group (3.2 ± 0.45 mm and 2.75 ± 0.55 mm, respectively). Despite the better results obtained for the Cht-coated surface group, further preclinical studies are necessary to confirm these results.

Fatigue behavior of thin wires and foils of multi-directionally forged commercial purity grade 2 Ti

Fatigue behavior of thin wires and foils of multi-directionally forged commercial purity grade 2 Ti

Hybrid Metal/Spinel Oxide Coating with Microcone Arrays to Stimulate a Photothermal-Augmented Oxygen Evolution Reaction.

To boost the kinetic process of the oxygen evolution reaction (OER), hybrid CoNiFe/Fe(Fe,Mo,Al)2 O4 coatings are deposited on pure Ti substrates (namely, CoNiFe/Fe(Fe,Mo,Al)2 O4 /Ti electrodes). This new coating features a dense inner layer together with an outer layer of microcone arrays (MCAs). The electrochemical surface area of the electrodes is modulated by controlling the geometrical factors of the MCAs. For the OER in 1.0 m KOH, the electrodes require minimum overpotentials of 245 and 333 mV to realize current densities of, respectively, 10 and 100 mA cm-2 . Furthermore, the high aspect ratio of the MCAs enables the electrodes to exhibit strong sunlight capture. Under 10 min of simulated 1.0 sun illumination, the electrode's temperature can rise by up to 108.2°C. The number of active sites and the OER reaction rateof the electrodes are further increased by photoassistance, with only 234 and 296 mV overpotentials, respectively, needed to generate current densities of 10 and 100 mA cm-2 with a Tafel slope as low as 40.9 mV dec-1 . Therefore, the application of this composite coating, which exhibits photothermal effects with respect to conventional Ti electrodes, provides an inspiration for further improvement of OER catalytic efficiency.

Decision Science Driven Selection of High-Temperature Conventional Ti Alloys for Aeroengines

Near-α Ti alloys find themselves in advanced aeroengines for applications of up to 600 °C, mainly as compressor components owing to their superior combination of ambient- and elevated-temperature mechanical properties and oxidation resistance. We evaluated, ranked, and selected near-α Ti alloys in the current literature for high-temperature applications in aeroengines driven by decision science by integrating multiple attribute decision making (MADM) and principal component analysis (PCA). A combination of 12 MADM methods ranked a list of 105 alloy variants based on the thermomechanical processing (TMP) conditions of 19 distinct near-α Ti alloys. PCA consolidated the ranks from various MADMs and identified top-ranked alloys for the intended applications as: Ti-6.7Al-1.9Sn-3.9Zr-4.6Mo-0.96W-0.23Si, Ti-4.8Al-2.2Sn-4.1Zr-2Mo-1.1Ge, Ti-6.6Al-1.75Sn-4.12Zr-1.91Mo-0.32W-0.1Si, Ti-4.9Al-2.3Sn-4.1Zr-2Mo-0.1Si-0.8Ge, Ti-4.8Al-2.3Sn-4.2Zr-2Mo, Ti-6.5Al-3Sn-4Hf-0.2Nb-0.4Mo-0.4Si-0.1B, Ti-5.8Al-4Sn-3.5Zr-0.7Mo-0.35Si-0.7Nb-0.06C, and Ti-6Al-3.5Sn-4.5Zr-2.0Ta-0.7Nb-0.5Mo-0.4Si. The alloys have the following metallurgical characteristics: bimodal matrix, aluminum equivalent preferably ~8, and nanocrystalline precipitates of Ti3Al, germanides, or silicides. The analyses, driven by decision science, make metallurgical sense and provide guidelines for developing next-generation commercial near-α Ti alloys. The investigation not only suggests potential replacement or substitute for existing alloys but also provides directions for improvement and development of titanium alloys over the current ones to push out some of the heavier alloys and thus help reduce the engine’s weight to gain advantage.

Synthesis of titanosilicate nanoparticles with high titanium content from a silsesquioxane-based precursor for a model epoxidation reaction.

In conventional hydrothermal synthesis of porous titanosilicate materials, undesired aggregation of TiO2 species during the synthesis limits the content of active four-coordinated Ti to an Si/Ti ratio of about 40. Aiming to increase the content of active four-coordinated Ti species, we report a bottom-up synthesis of titanosilicate nanoparticles using a Ti-incorporated cubic silsesquioxane cage as a precursor, which allowed incorporating a larger number of four-coordinated Ti species in the silica matrix to reach an Si/Ti ratio of 19. Even at this relatively high Ti concentration, the catalytic activity in the epoxidation of cyclohexene over the titanosilicate nanoparticles was comparable to that of a conventional reference Ti catalyst, Ti-MCM-41, with an Si/Ti ratio of 60. The activity per Ti site was not affected by the Ti content in the nanoparticles, suggesting that well dispersed and stabilized Ti species were the active sites.

ALD-grown two-dimensional TiSx metal contacts for MoS2 field-effect transistors.

Metal contacts to MoS2 field-effect transistors (FETs) play a determinant role in the device electrical characteristics and need to be chosen carefully. Because of the Schottky barrier (SB) and the Fermi level pinning (FLP) effects that occur at the contact/MoS2 interface, MoS2 FETs often suffer from high contact resistance (Rc). One way to overcome this issue is to replace the conventional 3D bulk metal contacts with 2D counterparts. Herein, we investigate 2D metallic TiSx (x ∼ 1.8) as top contacts for MoS2 FETs. We employ atomic layer deposition (ALD) for the synthesis of both the MoS2 channels as well as the TiSx contacts and assess the electrical performance of the fabricated devices. Various thicknesses of TiSx are grown on MoS2, and the resultant devices are electrically compared to the ones with the conventional Ti metal contacts. Our findings show that the replacement of 5 nm Ti bulk contacts with only ∼1.2 nm of 2D TiSx is beneficial in improving the overall device metrics. With such ultrathin TiSx contacts, the ON-state current (ION) triples and increases to ∼35 μA μm-1. Rc also reduces by a factor of four and reaches ∼5 MΩ μm. Such performance enhancements were observed despite the SB formed at the TiSx/MoS2 interface is believed to be higher than the SB formed at the Ti/MoS2 interface. These device metric improvements could therefore be mainly associated with an increased level of electrostatic doping in MoS2, as a result of using 2D TiSx for contacting the 2D MoS2. Our findings are also well supported by TCAD device simulations.

Lap-shear strength and fracture behavior of CFRP/3D-printed titanium alloy adhesive joint prepared by hot-press-aided co-bonding

Lap-shear strength and fracture behavior of CFRP/3D-printed titanium alloy adhesive joint prepared by hot-press-aided co-bonding

Nanocarbon ohmic electrodes fabricated by coaxial arc plasma deposition for phosphorus-doped diamond electronics application

n-Type (phosphorus-doped) diamond is a promising material for diamond-based electronic devices. However, realizing good ohmic contacts for phosphorus-doped diamonds limits their applications. Thus, the search for non-conventional ohmic contacts has become a hot topic for many researchers. In this work, nanocarbon ohmic electrodes with enhanced carrier collection efficiency were deposited by coaxial arc plasma deposition. The fabricated nanocarbon ohmic electrodes were extensively examined in terms of specific contact resistance and corrosion resistance. The circular transmission line model theory was used to estimate the charge collection efficiency of the nanocarbon ohmic electrodes in terms of specific contact resistance at a specific voltage range (5–10 V); they exhibited a specific contact resistance of 1 × 10−3 Ωcm2. The result revealed one order reduction in the specific contact resistance and, consequently, a potential drop at the diamond/electrode interface compared to the conventional Ti electrodes. Moreover, the fabricated nanocarbon electrodes exhibited high mechanical adhesion and chemical inertness over repeated acid treatments. In device applications, the nanocarbon electrodes were evaluated for Ni/n-type diamond Schottky diodes, and they exhibited nearly one order enhancement in the rectification ratio and a fast charge collection at lower biasing voltages.