[en] ObjectiveTo assess the feasibility of time-intensity curve (TIC) analysis of contrast-enhanced ultrasound (CEUS) in demonstrating features of benign and malignant thyroid nodules.

[en] High sphericity titanium carbide (TiC) powders with uniform distribution and favorable dispersity were obtained by thermal plasma treatment. By optimizing the process parameters, the spheroidization rate of TiC powders is almost 100%. During solidification process, a transformation from typical dendrite structure to cellular structure microstructure occurs with the increase of feeding speed. It ascribes to the decrease of heat absorbed from plasma torch, resulting in decreasing constitutional undercooling and improving solidified interface stability. Consequently, it promotes the formation of cellular structure. (paper)

[en] In this paper, we investigated the effect of titanium modification on microstructures and properties of carbidic austempered ductile iron (CADI) containing 3.72 wt.% C, 2.77 wt.% Si, and 0.51 wt.% Mn. The results showed that with the addition of 0.1 wt.% Ti, TiC particles were formed, and distributed in carbides and matrix. Microstructural observation indicated that the maximum diameter of graphite nodules decreased from 58 to 40 μm, and the shape of carbides transformed from network to fragmentation, which was related to the nucleation of the eutectic structure (γ + (Fe, Cr)₃C) where TiC particles act as the nucleus. After isothermal quenching at 300 °C, the hardness of Ti-bearing CADI was 3.5 HRC higher than ordinary CADI, and the impact toughness was increased by 14.3%. Additionally, due to the decrease in exfoliation, the wear loss of Ti-bearing CADI was 14.8% lower than ordinary CADI during the block-on-ring wear test at the surface load of 300 N.

[en] In order to improve the wear resistance of hardmetal cutting tools, coatings of hard materials were established. Especially the production of multilayer coatings, which combine useful properties of different materials was a topic of industrial and academic research. The present work examined the possibilities of combining diamond as basic layer with protective CVD layers of TiC, TiN, Ti(C,N) and Al₂O₃. All these combinations could be realized and some showed quite good adherence under strain, which offers possibilities for technical applications. (author)

[en] The paper presents a thermodynamic analysis for predicting the conditions for the plasma synthesis of TiC powders. The paper also investigates the effects of feeding rate and molar ratio. The experimental results show that TiC powders are synthesized by thermal plasma and the average size of the TiC powders is less than 100 nm

[en] Quantum-chemical calculations (QCCs) are performed using the VASP program to determine the possibility of obtaining a MAX phase of Ti₃AlC_2 – хВ_х (0.5 ≤ х ≤ 2) composition. It is shown that the isomorphic substitution of C atoms for B atoms destabilizes the system but does not destroy it. Theoretical X-ray patterns are calculated according to the QCC data. Differences between the X-ray patterns of Ti₃AlC₂ and Ti₃AlC_2 – хВ_х (0.5 ≤ х ≤ 2) crystals are revealed, by which the substitution of C atoms for B atoms can be proved.

[en] A general method for measuring the average particle diameter of powders by means of the Fisher Sub-Sieve-Sizer using any sample mass is described. The method was experimentally tested on standard sub-sieve powders and applied to iron and titanium-carbide sub-micron powders

[en] One approach for the fabrication of ceramic-metal composites is based on the pressureless impregnation of a porous ceramic preform by a molten metal. Molten Cu does not react with TiC and the wetting angle is close to 90^o. Nonetheless, molten Cu readily impregnates partially sintered TiC preforms. A model that describes the dependence of the critical contact angle for spontaneous impregnation by molten metals in partially sintered preforms on the level of densification and on the morphology of the particles was developed. For high aspect ratios of the particles forming the preform, wetting angles close to 90^o still allow impregnation by the molten metal. The results of the model were confirmed by infiltration of partially sintered TiC preforms with molten Cu and by fabrication of the TiC/Cu composites with various ceramic-to metal ratios. Decreasing of the metal content in the composite from 50 vol.% to 10 vol.% leads to a hardness increase from 250 to 1800 HV, and to the decrease of the bending strength from 960 to 280 MPa. The resistivity of these TiC/Cu composites decreases from 142 ohm cm to 25 ohm cm. (author)

[en] Luminescent copper nanoclusters (Cu NCs) are chosen to functionalize Ti₃C₂T_x MXene flakes to form a new kind of nanohybrid. It was applied to the determination of glutathione (GSH) via photoluminescence (PL). The Cu NCs and MXene flakes are in close contact, and the blue PL of the Cu NCs (with excitation/emission peaks at 380/425 nm) is quenched. The addition of GSH triggers the separation of the nanohybrid. This results in the recovery of PL. GSH also promotes the PL of Cu NCs via host-guest interactions. Thus, target recognition, corresponding signal output and further magnification are accomplished in a single step. Under optimum conditions, the nanohybrid can detect GSH in the 5.0 to 100 μM concentration range and with a 3.0 μM detection limit. The assay is very specific and shows high selectivity towards metal ions, small biomolecules, amino acids, and thiol containing molecules.

[en] In this present investigation, Al-bronze with fine (1–5 μm) TiC dispersoids containing 5 and 10 wt% were synthesized by self-propagating high-temperature synthesis process followed by casting route. The influence of TiC content in the Al-bronze matrix and test parameters such as applied load and sliding speed on the wear behavior was investigated. The microstructural examination clearly demonstrated that the distribution of TiC dispersoids were fairly uniform in Al-bronze matrix. The presence of α-Cu, β’and δ phases in the Al-bronze matrix was observed. Results also showed that as the TiC content was increased from 5 to 10 wt% hardness increased from 205 ± 3 to 266 ± 4 and density reduced from 7.25 g cm⁻³ to 7.1 g cm⁻³ respectively. Al-bronze-TiC composites showed better wear resistance as compared to the base Al-bronze alloy before reaching a transition load, beyond which the trend reversed. Further, increasing TiC content from 5 to 10 wt% led to an increase in the wear resistance of the composite at 1 m s⁻¹ speed up to a transition load 125 N and at higher speeds remain less than 5 wt% TiC composite. Seizure pressure decreased with increasing TiC content and speed. Operating material removal mechanisms were observed to be adhesion associated with abrasion. The adhesion dominates at higher loads and speeds while abrasion becoming significant at lower speeds and loads. Fragmented TiC particles were suggestive of these operating wear mechanisms. The interfacial cracking at TiC-matrix was also observed to contribute to material removal. (paper)